2019 Vol. 36, No. 4
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2019, 36(4): 629-637.
doi: 10.11833/j.issn.2095-0756.2019.04.001
Abstract:
Chlorella sp. is an algal attached to the branches and leaves of Torreya grandis 'Merrillii'. To explore the relationship the Chlorella sp. to Torreya grandis 'Merrillii' and to study the biological characteristics of the Chlorella sp., the Chlorella sp. was collected from T. grandis 'Merrillii' trees in three different regions and tested. According to an indoor culture, the morphological characteristics and living habits of the Chlorella sp. were observed, and the DNA of the Chlorella sp. extracted had a sequence specific amplification of 18S rDNA. An Internal Transcribed Spacer (ITS) gene sequence was also performed. The final sequence was aligned with the Basic Local Alignment Search Tool (BLAST) to draw a phylogenetic tree in neighbor-joining (NJ) method with three replications. Results showed two different forms of green algae, A and B. There were differences in the species of green algae in different areas, but they were mainly in the form of the A-type green algae. According to morphological identification results, the A-type Chlorella sp. was similar to the morphology of Chlorella ellipsoidea which could cause tomato green algae disease; the B-type Chlorella sp. was similar to the morphology of Ulothrix sp. which could cause cucumber green algae disease. However, the response of Chlorella sp. to pH was similar to that of Scenedesmus obliquus. The sequence alignment showed that the 18S rDNA and ITS gene sequences of the two forms of Chlorella sp. also had a high homology with Asterarcys quadricellulare of the Scenedesmaceae family with the similarity rate being 100%. Combining traditional morphological methods and molecular biology techniques, group A Chlorella sp. was identified as Asterarcys quadricellulare of the Scenedesmaceae family and group B Chlorella sp. identified as its variant. The two groups of Chlorella sp. had the same ITS region gene sequence as Scenedesmus sp. SM15_4 (KT778094.1) belonging to the Scenedesmaceae family. In conclusion, Chlorella sp. had favorable biological properties such as alkali resistance, a long growth cycle, and resistance to decay which helped it live on the Torreya grandis 'Merrillii' tree for a long time.
Chlorella sp. is an algal attached to the branches and leaves of Torreya grandis 'Merrillii'. To explore the relationship the Chlorella sp. to Torreya grandis 'Merrillii' and to study the biological characteristics of the Chlorella sp., the Chlorella sp. was collected from T. grandis 'Merrillii' trees in three different regions and tested. According to an indoor culture, the morphological characteristics and living habits of the Chlorella sp. were observed, and the DNA of the Chlorella sp. extracted had a sequence specific amplification of 18S rDNA. An Internal Transcribed Spacer (ITS) gene sequence was also performed. The final sequence was aligned with the Basic Local Alignment Search Tool (BLAST) to draw a phylogenetic tree in neighbor-joining (NJ) method with three replications. Results showed two different forms of green algae, A and B. There were differences in the species of green algae in different areas, but they were mainly in the form of the A-type green algae. According to morphological identification results, the A-type Chlorella sp. was similar to the morphology of Chlorella ellipsoidea which could cause tomato green algae disease; the B-type Chlorella sp. was similar to the morphology of Ulothrix sp. which could cause cucumber green algae disease. However, the response of Chlorella sp. to pH was similar to that of Scenedesmus obliquus. The sequence alignment showed that the 18S rDNA and ITS gene sequences of the two forms of Chlorella sp. also had a high homology with Asterarcys quadricellulare of the Scenedesmaceae family with the similarity rate being 100%. Combining traditional morphological methods and molecular biology techniques, group A Chlorella sp. was identified as Asterarcys quadricellulare of the Scenedesmaceae family and group B Chlorella sp. identified as its variant. The two groups of Chlorella sp. had the same ITS region gene sequence as Scenedesmus sp. SM15_4 (KT778094.1) belonging to the Scenedesmaceae family. In conclusion, Chlorella sp. had favorable biological properties such as alkali resistance, a long growth cycle, and resistance to decay which helped it live on the Torreya grandis 'Merrillii' tree for a long time.
2019, 36(4): 638-645.
doi: 10.11833/j.issn.2095-0756.2019.04.002
Abstract:
To reveal the distribution law of ant species in Sichuan Province, distribution patterns of ant species from Wanglang Nature Reserve and adjacent areas were determined using a sample-plot method. Results showed a total of 77 ant species belonging to 5 subfamilies and 37 genera of Formicidae. Air temperature and vegetation types were the main influences on ant species distribution and richness. More ant species inhabited low altitude vegetation due to the rich food supply, and forest gaps increased ant species richness. Conifer-broadleaf forests had the richest ant species among all vegetation types. More species nested in soils and foraged on the ground. Selection of nesting sites by ant species in different locations was related to climate factors. The rate of ant species foraging on tree canopies increased as latitude decreased. Most ant species had a relatively narrower distribution range and weaker ecological adaptive ability because they were sensitive to the environment. These species easily became endangered in local areas when disturbed by human beings. Overall, there was a rich but narrow-range of ant species that inhabited the Wanglang Nature Reserve and adjacent areas, and they had an important value in biodiversity conservation.
To reveal the distribution law of ant species in Sichuan Province, distribution patterns of ant species from Wanglang Nature Reserve and adjacent areas were determined using a sample-plot method. Results showed a total of 77 ant species belonging to 5 subfamilies and 37 genera of Formicidae. Air temperature and vegetation types were the main influences on ant species distribution and richness. More ant species inhabited low altitude vegetation due to the rich food supply, and forest gaps increased ant species richness. Conifer-broadleaf forests had the richest ant species among all vegetation types. More species nested in soils and foraged on the ground. Selection of nesting sites by ant species in different locations was related to climate factors. The rate of ant species foraging on tree canopies increased as latitude decreased. Most ant species had a relatively narrower distribution range and weaker ecological adaptive ability because they were sensitive to the environment. These species easily became endangered in local areas when disturbed by human beings. Overall, there was a rich but narrow-range of ant species that inhabited the Wanglang Nature Reserve and adjacent areas, and they had an important value in biodiversity conservation.
2019, 36(4): 646-655.
doi: 10.11833/j.issn.2095-0756.2019.04.003
Abstract:
Soil erosion is the main factor contributing to soil organic carbon (SOC) degradation. To explore the effect of water erosion on SOC and to seek effective soil and water conservation measures to protect SOC, four typical sample plots around Beijing were studied and manual simulation rainfall experiments were carried out. The results showed that (1) The order of soil organic carbon content in different plots was: soil accumulation zone, slight splash zone, rill erosion zone and strong erosion zone, water erosion had a great influence on the content of organic carbon in surface soil, and soil organic carbon loss in deep soil caused by severe erosion. (2) The average soil organic carbon content decreased with the increase of rainfall duration (soil erosion amount), and these decreases gradually diminished with the increase of rainfall duration (soil erosion amount). (3) For the accumulative regularity of soil organic carbon with different fish scale pit configurations, dry branches and fallen leaves coverage (32.7 g·kg-1) shows the highest content, followed by trees and low vegetation coverage (27.9 g·kg-1), trees only (23.5 g·kg-1), no measures (21.9 g·kg-1) and shrubs (21.5 g·kg-1). Among them, the surface coverage of dry branches, fallen leaves and low vegetation can effectively increase soil organic carbon. (4) The effects of different vegetation measures on soil organic carbon restoration from large to small were plantation, nursery, orchard and farmland, thus, suitable soil and water conservation measures should be taken to restore soil organic carbon.
Soil erosion is the main factor contributing to soil organic carbon (SOC) degradation. To explore the effect of water erosion on SOC and to seek effective soil and water conservation measures to protect SOC, four typical sample plots around Beijing were studied and manual simulation rainfall experiments were carried out. The results showed that (1) The order of soil organic carbon content in different plots was: soil accumulation zone, slight splash zone, rill erosion zone and strong erosion zone, water erosion had a great influence on the content of organic carbon in surface soil, and soil organic carbon loss in deep soil caused by severe erosion. (2) The average soil organic carbon content decreased with the increase of rainfall duration (soil erosion amount), and these decreases gradually diminished with the increase of rainfall duration (soil erosion amount). (3) For the accumulative regularity of soil organic carbon with different fish scale pit configurations, dry branches and fallen leaves coverage (32.7 g·kg-1) shows the highest content, followed by trees and low vegetation coverage (27.9 g·kg-1), trees only (23.5 g·kg-1), no measures (21.9 g·kg-1) and shrubs (21.5 g·kg-1). Among them, the surface coverage of dry branches, fallen leaves and low vegetation can effectively increase soil organic carbon. (4) The effects of different vegetation measures on soil organic carbon restoration from large to small were plantation, nursery, orchard and farmland, thus, suitable soil and water conservation measures should be taken to restore soil organic carbon.
2019, 36(4): 656-663.
doi: 10.11833/j.issn.2095-0756.2019.04.004
Abstract:
The temporal dynamic characteristics of soil total organic carbon (TOC) content, soil microbial biomass carbon (SMBC) content, and the fractal characteristics of soil TOC content with SMBC content of poplar (Populus deltoides 'I-35') plantations in coastal areas of northern Jiangsu Province were studied. Five nitrogen (N) levels were set in the sampled area, namely N0(N 0 g·m-2·a-1, control), N1(N 5 g·m-2·a-1), N2(N 10 g·m-2·a-1), N3(N 15 g·m-2·a-1), and N4(N 30 g·m-2·a-1). Soil samples for laboratory analyses were collected in April, June, August, October, and December 2015, and fractal theory was used to analyze the data. Results showed that the soil TOC mass fraction for the different concentrations of N added treatments were highly significant (P < 0.01), and the fractal dimension D of the soil TOC mass fraction with time ranged from 1.805 to 1.949. The fractal dimension D was ranked as N3 > N2 > N4 > N1 > N0. In June and October, different concentrations of N added treatments had no significant effects on the SMBC mass fraction (P > 0.05). In April, August, and December, the effects of the SMBC mass fraction for different concentrations of N added treatments were highly significant (P < 0.01), and the fractal dimension D of the soil TOC mass fraction with time ranged from 1.728 to 1.963. The fractal dimension D was ranked as N2 > N3 > N1 > N4 > N0. The fractal dimension D of the soil TOC mass fraction with the SMBC mass fraction for different concentrations of N added ranged from 2.207 to 2.342, and the fractal dimension D was ranked as N3 > N2 > N4 > N1 > N0. The fractal dimension D of the soil TOC mass fraction with the SMBC mass fraction for different months ranged from 1.650 to 6.149, and the fractal dimension D was ranked as June > October > April > August > December. N2 and N3 were obtained. Under the medium concentration of nitrogen treatment, the time dynamics of soil TOC and SMBC and soil TOC varies with SMBC were more random and complex than other concentrations; In June and October, the soil TOC varies with SMBC was more flexible and complex.
The temporal dynamic characteristics of soil total organic carbon (TOC) content, soil microbial biomass carbon (SMBC) content, and the fractal characteristics of soil TOC content with SMBC content of poplar (Populus deltoides 'I-35') plantations in coastal areas of northern Jiangsu Province were studied. Five nitrogen (N) levels were set in the sampled area, namely N0(N 0 g·m-2·a-1, control), N1(N 5 g·m-2·a-1), N2(N 10 g·m-2·a-1), N3(N 15 g·m-2·a-1), and N4(N 30 g·m-2·a-1). Soil samples for laboratory analyses were collected in April, June, August, October, and December 2015, and fractal theory was used to analyze the data. Results showed that the soil TOC mass fraction for the different concentrations of N added treatments were highly significant (P < 0.01), and the fractal dimension D of the soil TOC mass fraction with time ranged from 1.805 to 1.949. The fractal dimension D was ranked as N3 > N2 > N4 > N1 > N0. In June and October, different concentrations of N added treatments had no significant effects on the SMBC mass fraction (P > 0.05). In April, August, and December, the effects of the SMBC mass fraction for different concentrations of N added treatments were highly significant (P < 0.01), and the fractal dimension D of the soil TOC mass fraction with time ranged from 1.728 to 1.963. The fractal dimension D was ranked as N2 > N3 > N1 > N4 > N0. The fractal dimension D of the soil TOC mass fraction with the SMBC mass fraction for different concentrations of N added ranged from 2.207 to 2.342, and the fractal dimension D was ranked as N3 > N2 > N4 > N1 > N0. The fractal dimension D of the soil TOC mass fraction with the SMBC mass fraction for different months ranged from 1.650 to 6.149, and the fractal dimension D was ranked as June > October > April > August > December. N2 and N3 were obtained. Under the medium concentration of nitrogen treatment, the time dynamics of soil TOC and SMBC and soil TOC varies with SMBC were more random and complex than other concentrations; In June and October, the soil TOC varies with SMBC was more flexible and complex.
2019, 36(4): 664-669.
doi: 10.11833/j.issn.2095-0756.2019.04.005
Abstract:
Osmanthus fragrans is one of the top ten traditional flowers and a common landscaping tree in China. To better understand the function of AP1 in regulation of Osmanthus flowering, the OfAP1 gene was cloned from the Osmanthus cultivator 'Yanhonggui', and its function was analyzed through bioinformatics method and real time PCR. Our results showed that the cDNA length of OfAP1 was 750 bp (GenBank accession No. MH593222), in which the Open Reading Frame length was 720 bp, the amino acid was 239. The OfAP1 sequence alignment revealed high homology with other species ranging from 69% to 88%. Additionally, expression profiles showed that the expression of OfAP1 in flower buds was much higher than that in other tissues (root, stem, leaf, leaf bud and flower), and the expression was barely expressed in roots. During the development of flower bud, the OfAP1 showed higher expression in S1 (calyx and petal differentiation) stage than other stages. Thus, these results suggested that OfAP1 had a tissue specific expression and played an important role in flowering transformation, flower bud differentiation, and development of O. fragrans. And the results of OfAP1 can lay a foundation for further study of the molecular mechanism of O. fragrans.
Osmanthus fragrans is one of the top ten traditional flowers and a common landscaping tree in China. To better understand the function of AP1 in regulation of Osmanthus flowering, the OfAP1 gene was cloned from the Osmanthus cultivator 'Yanhonggui', and its function was analyzed through bioinformatics method and real time PCR. Our results showed that the cDNA length of OfAP1 was 750 bp (GenBank accession No. MH593222), in which the Open Reading Frame length was 720 bp, the amino acid was 239. The OfAP1 sequence alignment revealed high homology with other species ranging from 69% to 88%. Additionally, expression profiles showed that the expression of OfAP1 in flower buds was much higher than that in other tissues (root, stem, leaf, leaf bud and flower), and the expression was barely expressed in roots. During the development of flower bud, the OfAP1 showed higher expression in S1 (calyx and petal differentiation) stage than other stages. Thus, these results suggested that OfAP1 had a tissue specific expression and played an important role in flowering transformation, flower bud differentiation, and development of O. fragrans. And the results of OfAP1 can lay a foundation for further study of the molecular mechanism of O. fragrans.
2019, 36(4): 670-677.
doi: 10.11833/j.issn.2095-0756.2019.04.006
Abstract:
Hippophae rhamnoides have important ecological, economic and social benefits, so it is essential to understand the genetic variation of the species. Genetic diversity on 14 microsatellite loci was estimated for seven H. rhamnoides subspecies and 26 big grain sea buckthorn cultivars. The clustering of these individuals was analyzed by phylogenetic tree and Bayes cluster. Results indicated that H. rhamnoides subsp. sinensis had the highest genetic diversity, followed by H. rhamnoides subsp. yunnanensis; H. rhamnoides subsp. caucasica had the lowest genetic diversity. The phylogenetic tree based on individual genotypic distance classified all individuals into two big clades according to distribution, the Asian clade and the European clade. Most big grain sea buckthorn cultivars clustered with H. rhamnoides subsp. mongolica individuals collected from the Asian clade with a few individuals located between the two clades. The Bayesian cluster analysis found that all individuals could be classified into three or seven groups. For three groups, group one consisted of H. rhamnoides subsp. yunnanensis and H. rhamnoides subsp. sinensis; group two had the most cultivars and H. rhamnoides subsp. mongolica; and group three was H. rhamnoides subsp. fluviatilis, H. rhamnoides subsp. caucasica, and H. rhamnoides subsp. rhamnoides. For seven groups, all subspecies were classified into a different group with a few hybrids, and only H. rhamnoides subsp. rhamnoides showed a hybrid ancestry between H. rhamnoides subsp. fluviatilis and H. rhamnoides subsp. caucasica. There were also a few groups with mixed genotypes. Thus, genetic divergence among these seven H. rhamnoides subspecies was important, especially between subspecies distributed in different continents; whereas, big grain sea buckthorn cultivars were mostly selected from H. rhamnoides subsp. mongolica with a few of hybrid origin from H. rhamnoides subsp. mongolica and subspecies in Europe.
Hippophae rhamnoides have important ecological, economic and social benefits, so it is essential to understand the genetic variation of the species. Genetic diversity on 14 microsatellite loci was estimated for seven H. rhamnoides subspecies and 26 big grain sea buckthorn cultivars. The clustering of these individuals was analyzed by phylogenetic tree and Bayes cluster. Results indicated that H. rhamnoides subsp. sinensis had the highest genetic diversity, followed by H. rhamnoides subsp. yunnanensis; H. rhamnoides subsp. caucasica had the lowest genetic diversity. The phylogenetic tree based on individual genotypic distance classified all individuals into two big clades according to distribution, the Asian clade and the European clade. Most big grain sea buckthorn cultivars clustered with H. rhamnoides subsp. mongolica individuals collected from the Asian clade with a few individuals located between the two clades. The Bayesian cluster analysis found that all individuals could be classified into three or seven groups. For three groups, group one consisted of H. rhamnoides subsp. yunnanensis and H. rhamnoides subsp. sinensis; group two had the most cultivars and H. rhamnoides subsp. mongolica; and group three was H. rhamnoides subsp. fluviatilis, H. rhamnoides subsp. caucasica, and H. rhamnoides subsp. rhamnoides. For seven groups, all subspecies were classified into a different group with a few hybrids, and only H. rhamnoides subsp. rhamnoides showed a hybrid ancestry between H. rhamnoides subsp. fluviatilis and H. rhamnoides subsp. caucasica. There were also a few groups with mixed genotypes. Thus, genetic divergence among these seven H. rhamnoides subspecies was important, especially between subspecies distributed in different continents; whereas, big grain sea buckthorn cultivars were mostly selected from H. rhamnoides subsp. mongolica with a few of hybrid origin from H. rhamnoides subsp. mongolica and subspecies in Europe.
2019, 36(4): 678-686.
doi: 10.11833/j.issn.2095-0756.2019.04.007
Abstract:
This study was conducted to explore changes in relevant physiological indexes of cold-tolerant and cold-intolerant Casuarina equisetifolia as well as physiological mechanisms to adapt to a low-temperature environment, and to provide a basis for further study of cold resistance in C. equisetifolia. Using a substrate culture, the related physiological indexes of cold-tolerant (ZS7) and cold-intolerant (HN1) clones of C. equisetifolia seedlings with successive low temperature stresses at -2, -5, -8, and -11 ℃ for 2 h, as well as precise expression patterns with low temperature stresses of -5 ℃ for 1, 2, 5, 8, 16, 24, 48, and 72 h in climate chambers were studied. Results showed that for successive low temperature stresses, the rising amplitude of H2O2 and malondialdehyde (MDA) content in the cold-tolerant clones were significantly lower (P < 0.05) than in the cold-tolerant clones. Basically, the decreased amplitude of total chlorophyll, soluble protein, proline contents, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and ascorbate peroxidase (APX), as well as contents of glutathione reductase (GR), glutathione (GSH), and oxidized glutathione (GSSG) in ZS7 were significantly lower (P < 0.05) than in HN1. The GSH/GSSG ratio in ZS7 increased gradually; whereas, HN1 decreased first and then increased. For low temperature stress at -5 ℃, the rising amplitude or decrease in amplitude of physiological indexes in the two clones were different as was the time to its peak for physiological indexes of SOD, POD, CAT, APX, and GR as well as contents of total chlorophyll, soluble protein, proline, and GSH with ZS7 being generally higher than HN1. Thus, different clones showed different physiological response mechanisms to low temperature stress with the cold-tolerant clone resisting low temperature and enhancing cold resistance by maintaining the content of soluble protein and proline, promoting antioxidant enzyme activities and antioxidant contents, decreasing the accumulation of H2O2 and MDA, and inhibiting chlorophyll deterioration.
This study was conducted to explore changes in relevant physiological indexes of cold-tolerant and cold-intolerant Casuarina equisetifolia as well as physiological mechanisms to adapt to a low-temperature environment, and to provide a basis for further study of cold resistance in C. equisetifolia. Using a substrate culture, the related physiological indexes of cold-tolerant (ZS7) and cold-intolerant (HN1) clones of C. equisetifolia seedlings with successive low temperature stresses at -2, -5, -8, and -11 ℃ for 2 h, as well as precise expression patterns with low temperature stresses of -5 ℃ for 1, 2, 5, 8, 16, 24, 48, and 72 h in climate chambers were studied. Results showed that for successive low temperature stresses, the rising amplitude of H2O2 and malondialdehyde (MDA) content in the cold-tolerant clones were significantly lower (P < 0.05) than in the cold-tolerant clones. Basically, the decreased amplitude of total chlorophyll, soluble protein, proline contents, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and ascorbate peroxidase (APX), as well as contents of glutathione reductase (GR), glutathione (GSH), and oxidized glutathione (GSSG) in ZS7 were significantly lower (P < 0.05) than in HN1. The GSH/GSSG ratio in ZS7 increased gradually; whereas, HN1 decreased first and then increased. For low temperature stress at -5 ℃, the rising amplitude or decrease in amplitude of physiological indexes in the two clones were different as was the time to its peak for physiological indexes of SOD, POD, CAT, APX, and GR as well as contents of total chlorophyll, soluble protein, proline, and GSH with ZS7 being generally higher than HN1. Thus, different clones showed different physiological response mechanisms to low temperature stress with the cold-tolerant clone resisting low temperature and enhancing cold resistance by maintaining the content of soluble protein and proline, promoting antioxidant enzyme activities and antioxidant contents, decreasing the accumulation of H2O2 and MDA, and inhibiting chlorophyll deterioration.
2019, 36(4): 687-696.
doi: 10.11833/j.issn.2095-0756.2019.04.008
Abstract:
To reveal the physiological response mechanism for osmotic adjustment substances and antioxidant enzymes in a drought-resistant defense response system, seedlings of Osmanthus fragrans 'Boyejingui' were used as materials to artificially control the water levels and simulate drought stress and rewatering. Results showed that with prolongation of drought stress, there was a significant decrease (P < 0.05) in the relative water content (28.0%) and leaf water potential (76.9%) of leaves at 20 d compared to the ck. At 16 d of drought stress, the content of soluble sugar significantly increased 48.7% and betaine 53.5% compared with the ck (P < 0.05), and free proline significantly increased 3.44 times compared with the ck at 20 d (P < 0.05). Chlorophyll content at 20 d significantly decreased with the prolongation of drought stress (Chl a--19.0%, Chl b--16.2%, and Chl total--18.4%) (P < 0.05) compared with the ck. With prolongation of drought stress, the superoxide anion (O2·-) and hydrogen peroxide (H2O2) contents increased gradually, membrane lipid peroxidation increased, the membrane was damaged, and the damage rate of the leaves increased. When drought stress was 20 d, each indicator reached its maximum value. With prolongation of drought stress, at 16 d SOD significantly increased (P < 0.05) (31.7%) and CAT significantly increased (P < 0.05) (89.6%), with POD content significantly increasing (P < 0.05) 1.36 times compared with the ck. Thus, in the early stage of drought stress, 'Boyejingui' protected itself from drought stress by increasing osmotic adjustment substances and antioxidant enzyme activities; with the prolongation of stress time and an increase in stress level, the antioxidant enzyme activity decreased, the content of soluble sugar and betaine decreased slightly, and the content of free proline continued to increase indicating that osmotic adjustment substances played a major role in drought resistance and increased the drought resistance of plants; after rewatering, the physiological indexes of O. fragrans 'Boyejingui' were restored showing strong drought tolerance characteristics.
To reveal the physiological response mechanism for osmotic adjustment substances and antioxidant enzymes in a drought-resistant defense response system, seedlings of Osmanthus fragrans 'Boyejingui' were used as materials to artificially control the water levels and simulate drought stress and rewatering. Results showed that with prolongation of drought stress, there was a significant decrease (P < 0.05) in the relative water content (28.0%) and leaf water potential (76.9%) of leaves at 20 d compared to the ck. At 16 d of drought stress, the content of soluble sugar significantly increased 48.7% and betaine 53.5% compared with the ck (P < 0.05), and free proline significantly increased 3.44 times compared with the ck at 20 d (P < 0.05). Chlorophyll content at 20 d significantly decreased with the prolongation of drought stress (Chl a--19.0%, Chl b--16.2%, and Chl total--18.4%) (P < 0.05) compared with the ck. With prolongation of drought stress, the superoxide anion (O2·-) and hydrogen peroxide (H2O2) contents increased gradually, membrane lipid peroxidation increased, the membrane was damaged, and the damage rate of the leaves increased. When drought stress was 20 d, each indicator reached its maximum value. With prolongation of drought stress, at 16 d SOD significantly increased (P < 0.05) (31.7%) and CAT significantly increased (P < 0.05) (89.6%), with POD content significantly increasing (P < 0.05) 1.36 times compared with the ck. Thus, in the early stage of drought stress, 'Boyejingui' protected itself from drought stress by increasing osmotic adjustment substances and antioxidant enzyme activities; with the prolongation of stress time and an increase in stress level, the antioxidant enzyme activity decreased, the content of soluble sugar and betaine decreased slightly, and the content of free proline continued to increase indicating that osmotic adjustment substances played a major role in drought resistance and increased the drought resistance of plants; after rewatering, the physiological indexes of O. fragrans 'Boyejingui' were restored showing strong drought tolerance characteristics.
2019, 36(4): 697-703.
doi: 10.11833/j.issn.2095-0756.2019.04.009
Abstract:
To reveal the chlorophyll fluorescence characteristics of different internodes in the rapid growth period of Phyllostachys edulis, P. edulis shoots and stems were used as materials. The changes of the photosynthetic pigment content and chlorophyll fluorescence parameters for different internodes were studied by using a non-modulated chlorophyll fluorescence (YZQ-500) and the JIP-test data analysis method. Results showed that the content of chlorophyll a, chlorophyll b, and carotenoid in P. edulis stems significantly decreased (P < 0.05) with an increase of internodes. Light energy captured per unit area (TRo/CSo), quantum yield of electron transport per unit area (ETo/CSo), quantum yield of PS Ⅱ reaction center absorbing light energy for electron transfer (φEo), photosynthetic performance index (PIABS), and number of reaction centers (RC/CSo) significantly decreased (P < 0.05). Quantum for heat dissipation ratio (φDo), heat dissipation per unit area (DIo/CSo), and unit reaction center of wasted energy (DIo/RC) significantly decreased (P < 0.05). Since growth and development of the top and bottom internodes of P. edulis revealed activity in the middle and lower internodes having a stronger PS Ⅱ reaction center, a higher light energy conversion efficiency, and less energy dissipation enabling faster growth rates, and since photosynthetic functions of upper internodes were relatively weak meaning growth was slower, this study could be used as a reference value for clarifying the growth mechanism of P. edulis.
To reveal the chlorophyll fluorescence characteristics of different internodes in the rapid growth period of Phyllostachys edulis, P. edulis shoots and stems were used as materials. The changes of the photosynthetic pigment content and chlorophyll fluorescence parameters for different internodes were studied by using a non-modulated chlorophyll fluorescence (YZQ-500) and the JIP-test data analysis method. Results showed that the content of chlorophyll a, chlorophyll b, and carotenoid in P. edulis stems significantly decreased (P < 0.05) with an increase of internodes. Light energy captured per unit area (TRo/CSo), quantum yield of electron transport per unit area (ETo/CSo), quantum yield of PS Ⅱ reaction center absorbing light energy for electron transfer (φEo), photosynthetic performance index (PIABS), and number of reaction centers (RC/CSo) significantly decreased (P < 0.05). Quantum for heat dissipation ratio (φDo), heat dissipation per unit area (DIo/CSo), and unit reaction center of wasted energy (DIo/RC) significantly decreased (P < 0.05). Since growth and development of the top and bottom internodes of P. edulis revealed activity in the middle and lower internodes having a stronger PS Ⅱ reaction center, a higher light energy conversion efficiency, and less energy dissipation enabling faster growth rates, and since photosynthetic functions of upper internodes were relatively weak meaning growth was slower, this study could be used as a reference value for clarifying the growth mechanism of P. edulis.
2019, 36(4): 704-712.
doi: 10.11833/j.issn.2095-0756.2019.04.010
Abstract:
To understand the effects of nitrogen (N) deposition and biochar amendments on photosynthesis of new and old leaves of Moso bamboo (Phyllostachys edulis), effects of four N additions (N0: 0 kg·hm-2·a-1, N30: 30 kg·hm-2·a-1, N60: 60 kg·hm-2·a-1, and N90: 90 kg·hm-2·a-1) and three biochar amendments (BC0: 0 t·hm-2, BC20: 20 t·hm-2, and BC40: 40 t·hm-2) on photosynthesis and chlorophyll fluorescence characteristics of new and old leaves in two-year-old Moso bamboo were determined using LI-6400 portable photosynthesis system, PAM-2500 chlorophyll fluorescence spectrometer and SPAD-502 chlorophyll meter in Moso bamboo plantations (20 m×20 m). Results showed that N deposition and biochar amendment significantly increased (P < 0.05) the maximum net photosynthetic rate (Pmax), stomatal conductance (Gs), and transpiration rate (Tr) of new and old leaves. Biochar amendments significantly increased (P < 0.001) effective quantum yield of Photosystem Ⅱ (PS-Ⅱ)[Y(Ⅱ)] and potential activities of PS-Ⅱ (Fv/F0) of old leaves. In combination with both N depositions (N30 and N60), BC20 significantly decreased (P < 0.001) the relative chlorophyll content (SPAD) of old leaves compared with the N depositions alone. The SPAD of new leaves for N60-BC20 was significantly lower (P < 0.001) than N60-BC0. Also, both biochar amendments in combination with N60 significantly increased (P < 0.001) maximal potential quantum yield of PS-Ⅱ (Fv/Fm), Fv/Fo, and Y(Ⅱ) of new and old leaves compared to N depositions alone. However, biochar amendments in combination with N90 significantly decreased (P < 0.001) both Fv/Fm and Fv/Fo of new and old leaves compared to N depositions alone. In conclusion, this study demonstrated that biochar amendments promoted photosynthesis of leaves and thus increased productivity of a Moso bamboo forest with the background of globally increasing N deposition.
To understand the effects of nitrogen (N) deposition and biochar amendments on photosynthesis of new and old leaves of Moso bamboo (Phyllostachys edulis), effects of four N additions (N0: 0 kg·hm-2·a-1, N30: 30 kg·hm-2·a-1, N60: 60 kg·hm-2·a-1, and N90: 90 kg·hm-2·a-1) and three biochar amendments (BC0: 0 t·hm-2, BC20: 20 t·hm-2, and BC40: 40 t·hm-2) on photosynthesis and chlorophyll fluorescence characteristics of new and old leaves in two-year-old Moso bamboo were determined using LI-6400 portable photosynthesis system, PAM-2500 chlorophyll fluorescence spectrometer and SPAD-502 chlorophyll meter in Moso bamboo plantations (20 m×20 m). Results showed that N deposition and biochar amendment significantly increased (P < 0.05) the maximum net photosynthetic rate (Pmax), stomatal conductance (Gs), and transpiration rate (Tr) of new and old leaves. Biochar amendments significantly increased (P < 0.001) effective quantum yield of Photosystem Ⅱ (PS-Ⅱ)[Y(Ⅱ)] and potential activities of PS-Ⅱ (Fv/F0) of old leaves. In combination with both N depositions (N30 and N60), BC20 significantly decreased (P < 0.001) the relative chlorophyll content (SPAD) of old leaves compared with the N depositions alone. The SPAD of new leaves for N60-BC20 was significantly lower (P < 0.001) than N60-BC0. Also, both biochar amendments in combination with N60 significantly increased (P < 0.001) maximal potential quantum yield of PS-Ⅱ (Fv/Fm), Fv/Fo, and Y(Ⅱ) of new and old leaves compared to N depositions alone. However, biochar amendments in combination with N90 significantly decreased (P < 0.001) both Fv/Fm and Fv/Fo of new and old leaves compared to N depositions alone. In conclusion, this study demonstrated that biochar amendments promoted photosynthesis of leaves and thus increased productivity of a Moso bamboo forest with the background of globally increasing N deposition.
2019, 36(4): 713-722.
doi: 10.11833/j.issn.2095-0756.2019.04.011
Abstract:
The analysis method, type, and mechanism of the stability of azadirachtin content in neem (Azadirachta indica) cultivars were discussed in order to explores the methods to establish the stability analysis of the quality and quantity fraction of neem cultivars, and probes into the stability types and mechanisms. Based on data obtained from the mass fraction of azadirachtin in seven neem clonal seeds, the effects of five analytical models (Stability Variance, Finlay-Wilkinson, Eberhart-Russell, AMMI-1, and Environmental Variance) from the stability assessment of azadirachtin components were compared using a SAS PROC MIXED procedure. An Akaike Information Criterion (cAIC) of maximum likelihood value was also conducted to evaluate and select the optimal model and to deduce stability types and mechanisms. Seeds were collected from 6 superior cultivars (Ld0505, At0515, Ww0401, Dhg0507, Wx0423, Wx0416)of pesticide type neem and average neem (ck), and the experiment was designed with random complete block design, with 7 cultivars being one plot and 3 repetitions (plants spacing 4 m×4 m), and then azadirachtin concentrations in seed kernels were tested. The results showed that the cAIC values of azadirachtin A and azadirachtin B of Finlay-Wilkinson and AMMI-1 models were the minimum, respectively -17.3 and -5.8. The stability parameters of the mass fraction of azadirachtin A and azadirachtin B were basically the same, and the stability sequencing was Wx0423 > Wx0416 > Dhg507 > average wood (ck) > At0515 > Ld0505 > Ww0401 and average wood (ck) > Wx0416 > Wx0423 > Dhg0507 > Ld0505 > Ww0401 > At0515. The significant difference in effect between azadirachtin A and azadirachtin B was extremely significant (P < 0.01) and significant (P < 0.05), respectively. It was proved that the stability of azadirachtin A and azadirachtin B would change predictably with the change of environmental conditions, namely dynamic stability, and their genetic mechanism was controlled by heredity. Finlay-Wilkinson and AMMI-1 are suitable for the Stability analysis of the quality quantity fraction of neem seeds, while the Stability Variance, Eberhart-Russell and Environmental Variance models are not applicable. The stability of azadirachtin A and azadirachtin B was dynamic, and the stability was mostly dependent on individual buffering. The comprehensive evaluation of stability based on multi-model analysis is more efficient.
The analysis method, type, and mechanism of the stability of azadirachtin content in neem (Azadirachta indica) cultivars were discussed in order to explores the methods to establish the stability analysis of the quality and quantity fraction of neem cultivars, and probes into the stability types and mechanisms. Based on data obtained from the mass fraction of azadirachtin in seven neem clonal seeds, the effects of five analytical models (Stability Variance, Finlay-Wilkinson, Eberhart-Russell, AMMI-1, and Environmental Variance) from the stability assessment of azadirachtin components were compared using a SAS PROC MIXED procedure. An Akaike Information Criterion (cAIC) of maximum likelihood value was also conducted to evaluate and select the optimal model and to deduce stability types and mechanisms. Seeds were collected from 6 superior cultivars (Ld0505, At0515, Ww0401, Dhg0507, Wx0423, Wx0416)of pesticide type neem and average neem (ck), and the experiment was designed with random complete block design, with 7 cultivars being one plot and 3 repetitions (plants spacing 4 m×4 m), and then azadirachtin concentrations in seed kernels were tested. The results showed that the cAIC values of azadirachtin A and azadirachtin B of Finlay-Wilkinson and AMMI-1 models were the minimum, respectively -17.3 and -5.8. The stability parameters of the mass fraction of azadirachtin A and azadirachtin B were basically the same, and the stability sequencing was Wx0423 > Wx0416 > Dhg507 > average wood (ck) > At0515 > Ld0505 > Ww0401 and average wood (ck) > Wx0416 > Wx0423 > Dhg0507 > Ld0505 > Ww0401 > At0515. The significant difference in effect between azadirachtin A and azadirachtin B was extremely significant (P < 0.01) and significant (P < 0.05), respectively. It was proved that the stability of azadirachtin A and azadirachtin B would change predictably with the change of environmental conditions, namely dynamic stability, and their genetic mechanism was controlled by heredity. Finlay-Wilkinson and AMMI-1 are suitable for the Stability analysis of the quality quantity fraction of neem seeds, while the Stability Variance, Eberhart-Russell and Environmental Variance models are not applicable. The stability of azadirachtin A and azadirachtin B was dynamic, and the stability was mostly dependent on individual buffering. The comprehensive evaluation of stability based on multi-model analysis is more efficient.
2019, 36(4): 723-732.
doi: 10.11833/j.issn.2095-0756.2019.04.012
Abstract:
To effectively protect and utilize the wild germplasm resources of Cerasus, 50 morphological traits of leaves and branches from eight Cerasus species (six species and two varieties) were investigated. Based on morphological data which was randomly measured fifty leaves and twelve branches from ten plants of each species, the interspecific and intraspecific variation of morphological traits and the relationship between them were analyzed by ANOVA and principal component analysis (PCA). Results showed that the differences for 17 quantitative characters among the eight species were highly significant (P < 0.01). The interspecific coefficient of variation (CV) of quantitative characters ranged from 14.05% to 64.15% with the largest value being diameter at breast height (DHB) and the smallest being leaf length. The CVs for stipule length, leaf area, stipule width, petiole length/leaf length, and petiole length were > 30% as were branch traits except for branch angle. Most of the intraspecific CVs were less than interspecific variations. The average diversity indexes of qualitative characters ranged from 0.03 to 1.28 with the average diversity indexes of leaf index, young leaf color, mature leaf color (abaxial), branchlet color, twig color, and branch color being > 0.95. Based on the PCA, the quantitative characters and seven qualitative characters with high diversity indexes were divided into eight principle components, with the cumulative contribution rate reaching 76.85%. Also, 91 wild germplasm resources were divided into 5 groups, namely Cerasus subhirtella, C. conradinae, C. discoidea, C. dielsiana, and C. serrulata. The two varieties were clustered into relevant species, and Cerasus schneideriana was not considered as an independent group. This research indicated strong differences in the traits of leaves and branches of Cerasus species, and the PCA was suitable for analyzing leaf and branch traits, which can screen and exploit superior germplasm resources efficiently.
To effectively protect and utilize the wild germplasm resources of Cerasus, 50 morphological traits of leaves and branches from eight Cerasus species (six species and two varieties) were investigated. Based on morphological data which was randomly measured fifty leaves and twelve branches from ten plants of each species, the interspecific and intraspecific variation of morphological traits and the relationship between them were analyzed by ANOVA and principal component analysis (PCA). Results showed that the differences for 17 quantitative characters among the eight species were highly significant (P < 0.01). The interspecific coefficient of variation (CV) of quantitative characters ranged from 14.05% to 64.15% with the largest value being diameter at breast height (DHB) and the smallest being leaf length. The CVs for stipule length, leaf area, stipule width, petiole length/leaf length, and petiole length were > 30% as were branch traits except for branch angle. Most of the intraspecific CVs were less than interspecific variations. The average diversity indexes of qualitative characters ranged from 0.03 to 1.28 with the average diversity indexes of leaf index, young leaf color, mature leaf color (abaxial), branchlet color, twig color, and branch color being > 0.95. Based on the PCA, the quantitative characters and seven qualitative characters with high diversity indexes were divided into eight principle components, with the cumulative contribution rate reaching 76.85%. Also, 91 wild germplasm resources were divided into 5 groups, namely Cerasus subhirtella, C. conradinae, C. discoidea, C. dielsiana, and C. serrulata. The two varieties were clustered into relevant species, and Cerasus schneideriana was not considered as an independent group. This research indicated strong differences in the traits of leaves and branches of Cerasus species, and the PCA was suitable for analyzing leaf and branch traits, which can screen and exploit superior germplasm resources efficiently.
2019, 36(4): 733-740.
doi: 10.11833/j.issn.2095-0756.2019.04.013
Abstract:
To determine the effects of arbuscular mycorrhizal fungi (AMF) on heat resistance of Rhododendron and to choose the best AMF, Rhododendron 'Bi Zhi' was selected as the test material. Three AMF, Glomus intraradices (Gi), Glomus mosseae (Gm), and Glomus etunicatum (Ge) were used to study the effects on physiological and biochemical indexes of Rhododendron under high temperature stress. Analysis included the average subordinate function method to comprehensively evaluate the heat resistance with the three kinds of AMF and azalea. A comparison of the leaf anatomic structural characteristics before and after inoculation with the three fungi was conducted for heat stress by observing the performance. Results showed that under high temperature stress, the three AMF could colonize azalea roots. The colonization percentage of Gi was the highest (49.6%), while Ge the lest (37.4%). The contents of soluble sugar, soluble protein, chlorophyll, and proline increased compared to the control. At the same time the contents of malondialdehyde (MDA) and membrane permeability in azalea inoculated Gi stayed at a relatively low level. Furthermore, the anatomic structure of leaves inoculated with AMF was less damaged, and the ratio of palisade sponge tissue of the AMF inoculated leaf was much higher than that of the non-AMF control. According to the average subordinate function method, the heat resistance for azalea with AMF was in the order Gi > Gm > Ge. Thus, AMF could improve the heat resistance of the azalea cultivars to some extent.
To determine the effects of arbuscular mycorrhizal fungi (AMF) on heat resistance of Rhododendron and to choose the best AMF, Rhododendron 'Bi Zhi' was selected as the test material. Three AMF, Glomus intraradices (Gi), Glomus mosseae (Gm), and Glomus etunicatum (Ge) were used to study the effects on physiological and biochemical indexes of Rhododendron under high temperature stress. Analysis included the average subordinate function method to comprehensively evaluate the heat resistance with the three kinds of AMF and azalea. A comparison of the leaf anatomic structural characteristics before and after inoculation with the three fungi was conducted for heat stress by observing the performance. Results showed that under high temperature stress, the three AMF could colonize azalea roots. The colonization percentage of Gi was the highest (49.6%), while Ge the lest (37.4%). The contents of soluble sugar, soluble protein, chlorophyll, and proline increased compared to the control. At the same time the contents of malondialdehyde (MDA) and membrane permeability in azalea inoculated Gi stayed at a relatively low level. Furthermore, the anatomic structure of leaves inoculated with AMF was less damaged, and the ratio of palisade sponge tissue of the AMF inoculated leaf was much higher than that of the non-AMF control. According to the average subordinate function method, the heat resistance for azalea with AMF was in the order Gi > Gm > Ge. Thus, AMF could improve the heat resistance of the azalea cultivars to some extent.
2019, 36(4): 741-748.
doi: 10.11833/j.issn.2095-0756.2019.04.014
Abstract:
Forest site conditions affect the growth of trees. To fully delve into the internal relationship between site factors and stand growth factors, Chinese fir (Cunninghamia lanceolata) forest was taken as the research object, and a site index model based on Richard's theoretical equation was established using dynamic monitoring data of forest resources in Lin'an District of Hangzhou. The Apriori algorithm was used to explore the association rules between site and forest stand growth factors. Results showed 175 rules obtained with confidence over 80% and support over 10% and 20 rules of "stand growth factors-site factors" were extracted from them. The site factors which influenced site quality of Chinese fir timber forests in Lin'an District were altitude, slope position, slope aspect, gradient, soil type, soil texture, soil thickness, humus depth, species in the undergrowth, and degree of cover on the undergrowth through the rules. The rules revealed variation rules and hidden associations between site factors and stand quality, site factors and stand growth factors, as well as stand factors and stand age.
Forest site conditions affect the growth of trees. To fully delve into the internal relationship between site factors and stand growth factors, Chinese fir (Cunninghamia lanceolata) forest was taken as the research object, and a site index model based on Richard's theoretical equation was established using dynamic monitoring data of forest resources in Lin'an District of Hangzhou. The Apriori algorithm was used to explore the association rules between site and forest stand growth factors. Results showed 175 rules obtained with confidence over 80% and support over 10% and 20 rules of "stand growth factors-site factors" were extracted from them. The site factors which influenced site quality of Chinese fir timber forests in Lin'an District were altitude, slope position, slope aspect, gradient, soil type, soil texture, soil thickness, humus depth, species in the undergrowth, and degree of cover on the undergrowth through the rules. The rules revealed variation rules and hidden associations between site factors and stand quality, site factors and stand growth factors, as well as stand factors and stand age.
2019, 36(4): 749-756.
doi: 10.11833/j.issn.2095-0756.2019.04.015
Abstract:
Spatial structure is important in describing forest stand structure and change, which is an indicator to the success of forest management. A 100 m×100 m permanent sample plot of the Pinus massoniana near-mature forest was established in Central Guizhou with random sampling method, the tree height, diameter at breast height, and coordinates of each tree were determined as the base data based on a 10 m×10 m grid. The characteristics of forest spatial structure were analyzed by univariate and bivariate distributions of mingling, dominance, and uniform angle index. Results showed that (1) P. massoniana was dominant in number and basal area, the intraspecific competition among P. massoniana trees greatly affected the growth of trees. The whole stand was dominated by a zero-mixed degree with low spatial heterogeneity. (2) For the whole forest stand, most of the distributions were random, there was no significant difference in the tree diameter, and the main spatial distribution pattern of associated tree species was a concentrated distribution. (3) Simulated cuttings contributed to the regulation of spatial structure, which improved the spatial distribution pattern and provided the favorable spatial conditions for positive succession of the forest community as well as healthy growth of the dominant tree populations.
Spatial structure is important in describing forest stand structure and change, which is an indicator to the success of forest management. A 100 m×100 m permanent sample plot of the Pinus massoniana near-mature forest was established in Central Guizhou with random sampling method, the tree height, diameter at breast height, and coordinates of each tree were determined as the base data based on a 10 m×10 m grid. The characteristics of forest spatial structure were analyzed by univariate and bivariate distributions of mingling, dominance, and uniform angle index. Results showed that (1) P. massoniana was dominant in number and basal area, the intraspecific competition among P. massoniana trees greatly affected the growth of trees. The whole stand was dominated by a zero-mixed degree with low spatial heterogeneity. (2) For the whole forest stand, most of the distributions were random, there was no significant difference in the tree diameter, and the main spatial distribution pattern of associated tree species was a concentrated distribution. (3) Simulated cuttings contributed to the regulation of spatial structure, which improved the spatial distribution pattern and provided the favorable spatial conditions for positive succession of the forest community as well as healthy growth of the dominant tree populations.
2019, 36(4): 757-763.
doi: 10.11833/j.issn.2095-0756.2019.04.016
Abstract:
To efficiently calculate and predict forest stock and biomass, diameter at breast height (DBH), a basic factor of a tree, was used in a regression model. In this study, Ginkgo biloba was used as the research object. Image data was obtained with an unmanned aerial vehicle (UAV), and using the method of structure from motion (SFM), a digital surface model and an orthophoto map were generated. Next, the canopy area (AC), crown width (WC) and tree height (H) of G. biloba were extracted. Then, one-way regression models (AC-DBH, WC-DBH, H-DBH), binary regression models (AC&WC-DBH, AC&H-DBH, WC&H-DBH), and a ternary regression model (AC&WC&H-DBH) were established. Results of 52 groups of fitted samples showed that the AC&WC&H-DBH model had the highest coefficient of determination (R2 = 0.825 0) and the lowest root mean square error (ERMS = 0.959 1). Results of 19 groups of test samples showed that the DBH error rate for the AC&WC&H-DBH model was 4.20%, which was less than the allowable error value (5%) for the A-type forest resource DBH factor. Thus, a high precision DBH value could be calculated using the three parameters of canopy area, crown width, and tree height, thereby providing a new idea for automated forest resource surveying and monitoring.
To efficiently calculate and predict forest stock and biomass, diameter at breast height (DBH), a basic factor of a tree, was used in a regression model. In this study, Ginkgo biloba was used as the research object. Image data was obtained with an unmanned aerial vehicle (UAV), and using the method of structure from motion (SFM), a digital surface model and an orthophoto map were generated. Next, the canopy area (AC), crown width (WC) and tree height (H) of G. biloba were extracted. Then, one-way regression models (AC-DBH, WC-DBH, H-DBH), binary regression models (AC&WC-DBH, AC&H-DBH, WC&H-DBH), and a ternary regression model (AC&WC&H-DBH) were established. Results of 52 groups of fitted samples showed that the AC&WC&H-DBH model had the highest coefficient of determination (R2 = 0.825 0) and the lowest root mean square error (ERMS = 0.959 1). Results of 19 groups of test samples showed that the DBH error rate for the AC&WC&H-DBH model was 4.20%, which was less than the allowable error value (5%) for the A-type forest resource DBH factor. Thus, a high precision DBH value could be calculated using the three parameters of canopy area, crown width, and tree height, thereby providing a new idea for automated forest resource surveying and monitoring.
2019, 36(4): 764-773.
doi: 10.11833/j.issn.2095-0756.2019.04.017
Abstract:
As a unique species of China, Phoebe bournei, a protected second-level rare and vulnerable tree species, has had important ecological and economic value. Within the research area of Anfu County in Jiangxi Province, a natural secondary P. bournei forest was taken as the research object, and data was obtained by means of a typical sample investigation and whole tree harvesting. Biomass allocation patterns of total tree and each component (stem, root, branch, and leaf) of P. bournei were analyzed with branch diameter levels of 2, 4, 6, and 8 cm and with DBH levels of 14, 18, 22, 26, and 30 cm as well as above. Compatible biomass models were established using a nonlinear measurement error model. Results showed (1) Significant differences among the biomass allocation ratios of primary branch, secondary branch, and leaf at different branch diameter levels (P < 0.05). Live branch biomass mainly occurred in the lower canopy layers, and was significantly higher than the upper layer (P < 0.05). (2) Biomass allocation ratios of each organ were as follows: stem > root > branch > leaf. The biomass of organs at different DBH levels was significantly different (P < 0.05). The biomass allocation ratio of roots was significantly different (P < 0.05); whereas, the biomass allocation ratios of other organs were not significantly different (P > 0.05). (3) The precision values of the compatible biomass model based on the nonlinear measurement error model for biomass were whole plant (91.8%), aboveground (91.0%), root (90.2%), crown (85.1%), stem (91.6%), branch (86.8%), and leaf (71.0%). Overall, the model was a good fit.
As a unique species of China, Phoebe bournei, a protected second-level rare and vulnerable tree species, has had important ecological and economic value. Within the research area of Anfu County in Jiangxi Province, a natural secondary P. bournei forest was taken as the research object, and data was obtained by means of a typical sample investigation and whole tree harvesting. Biomass allocation patterns of total tree and each component (stem, root, branch, and leaf) of P. bournei were analyzed with branch diameter levels of 2, 4, 6, and 8 cm and with DBH levels of 14, 18, 22, 26, and 30 cm as well as above. Compatible biomass models were established using a nonlinear measurement error model. Results showed (1) Significant differences among the biomass allocation ratios of primary branch, secondary branch, and leaf at different branch diameter levels (P < 0.05). Live branch biomass mainly occurred in the lower canopy layers, and was significantly higher than the upper layer (P < 0.05). (2) Biomass allocation ratios of each organ were as follows: stem > root > branch > leaf. The biomass of organs at different DBH levels was significantly different (P < 0.05). The biomass allocation ratio of roots was significantly different (P < 0.05); whereas, the biomass allocation ratios of other organs were not significantly different (P > 0.05). (3) The precision values of the compatible biomass model based on the nonlinear measurement error model for biomass were whole plant (91.8%), aboveground (91.0%), root (90.2%), crown (85.1%), stem (91.6%), branch (86.8%), and leaf (71.0%). Overall, the model was a good fit.
2019, 36(4): 774-782.
doi: 10.11833/j.issn.2095-0756.2019.04.018
Abstract:
Estimating the value of ecosystem services in coastal wetlands could provide important information for the protection and restoration of wetland ecosystems and decision-making. To reveal the spatio-temporal variation of ecosystem services value (ESV), the Yancheng coastal zone, a fragile region with a high intensity of reclamation activities, was taken as the research area, the thematic map (TM) and enhanced thematic map (ETM) remote sensing images of 1997, 2007, and 2014 were processed to obtain landscape type information. The ESV of the three periods was estimated by a grid unit in the study region and explored through spatial and temporal scales. Results showed that the total value of the ESV in Yancheng coastal zone decreased from 13.433 billion Yuan in 1997 to 9.713 billion Yuan in 2014 with the main reason being the decrease of Phragmites australis marshes, Suaeda salsa marshes, and river area in natural wetlands. ESV also changed significantly in space. The area and spatial distribution of the highest ESV decreased significantly, and the spatial distribution and area of the lower ESV increased gradually. The spatial autocorrelation index showed that ESV had a significant positive correlation and spatial connection which showed a downward curve on the whole. The sensitivity index of the research area was less than 1 from 1997 to 2014 which showed that the results of ESV estimation were credible. Thus, the trade-offs and synergies among different ecosystem services in coastal zones should be explored with more attention being paid to protection of natural wetlands, such as P. australis marshes, S. salsa marshes, and rivers, in future ecosystem restoration and management and with wetlands being rationally planned to realize the sustainable development and utilization of the coastal wetland system.
Estimating the value of ecosystem services in coastal wetlands could provide important information for the protection and restoration of wetland ecosystems and decision-making. To reveal the spatio-temporal variation of ecosystem services value (ESV), the Yancheng coastal zone, a fragile region with a high intensity of reclamation activities, was taken as the research area, the thematic map (TM) and enhanced thematic map (ETM) remote sensing images of 1997, 2007, and 2014 were processed to obtain landscape type information. The ESV of the three periods was estimated by a grid unit in the study region and explored through spatial and temporal scales. Results showed that the total value of the ESV in Yancheng coastal zone decreased from 13.433 billion Yuan in 1997 to 9.713 billion Yuan in 2014 with the main reason being the decrease of Phragmites australis marshes, Suaeda salsa marshes, and river area in natural wetlands. ESV also changed significantly in space. The area and spatial distribution of the highest ESV decreased significantly, and the spatial distribution and area of the lower ESV increased gradually. The spatial autocorrelation index showed that ESV had a significant positive correlation and spatial connection which showed a downward curve on the whole. The sensitivity index of the research area was less than 1 from 1997 to 2014 which showed that the results of ESV estimation were credible. Thus, the trade-offs and synergies among different ecosystem services in coastal zones should be explored with more attention being paid to protection of natural wetlands, such as P. australis marshes, S. salsa marshes, and rivers, in future ecosystem restoration and management and with wetlands being rationally planned to realize the sustainable development and utilization of the coastal wetland system.
2019, 36(4): 783-792.
doi: 10.11833/j.issn.2095-0756.2019.04.019
Abstract:
The microclimatic environment created by a plant community could provide wonderful rest space for people. This study focused on how to regulate the microclimate by improving the structure and characteristics of a plant community. The microclimatic environment of Nanjing, a typical city with high temperature and humidity in summer, was studied. Using simulation software, ENVI-met, pure forests in ideal conditions were selected to analyze the impact of five common canopy shapes (cylindrical, spheroidal, obovate, triangular, and inverted triangular) and three layout forms (regular-scatter, centralized-block, and natural-distribution) on temperature, humidity, and thermal comfort (PMV) of a plant community in Nanjing during summer. Results indicated that canopy shapes and layout forms had a significant influence on the cooling and humidification effect of a plant community (P < 0.05). The tree communities with an obovate canopy or inverted triangular canopy, which were typically large in the upper part of the canopy and small in the lower part, had the highest cooling and humidification efficiency which could provide the best thermal comfort experience. The cooling and humidification efficiency of the communities planted in a centralized-block form were higher than those in a regular-scatter or natural-distribution form; whereas, the thermal comfort experience of the community planted in a natural-distribution form was better.
The microclimatic environment created by a plant community could provide wonderful rest space for people. This study focused on how to regulate the microclimate by improving the structure and characteristics of a plant community. The microclimatic environment of Nanjing, a typical city with high temperature and humidity in summer, was studied. Using simulation software, ENVI-met, pure forests in ideal conditions were selected to analyze the impact of five common canopy shapes (cylindrical, spheroidal, obovate, triangular, and inverted triangular) and three layout forms (regular-scatter, centralized-block, and natural-distribution) on temperature, humidity, and thermal comfort (PMV) of a plant community in Nanjing during summer. Results indicated that canopy shapes and layout forms had a significant influence on the cooling and humidification effect of a plant community (P < 0.05). The tree communities with an obovate canopy or inverted triangular canopy, which were typically large in the upper part of the canopy and small in the lower part, had the highest cooling and humidification efficiency which could provide the best thermal comfort experience. The cooling and humidification efficiency of the communities planted in a centralized-block form were higher than those in a regular-scatter or natural-distribution form; whereas, the thermal comfort experience of the community planted in a natural-distribution form was better.
2019, 36(4): 793-800.
doi: 10.11833/j.issn.2095-0756.2019.04.020
Abstract:
To build and optimize the plant landscape with low impact development, plant community characteristics and species diversity in a low-impact development demonstration area, being key to ecological benefits of plant communities, were determined. Taking the plant community in the low-impact development demonstration area of Zhenjiang City as the research object, plant, community quantity characteristics, community structural factors, community diversity, and community clustering were analyzed through typical sample and quantitative analysis methods including a cluster analysis and principal factor analysis. 48 sample plots were set randomly with the 100 m2 standard plot as the main plot, and 204 squares were set in total. Results showed(1) There were 74 families, 147 genera, and 181 species of vascular plants. Pterocarya stenoptera, Cinnamomum camphora, and Koelreuteria integrifoliola were the dominant tree species; Photinia×fraseri, Ligustrum japonicum, and Hypericum monogynum were the dominant shrub species; and Cynodon dactylon, Iris tectorum, and Ophiopogon japonicus were the dominant herb species. (2) The plant community was described by five factors: tree characteristics, ratio of tree to shrub traits, shrub diversity, herb characteristics, and tree diversity. (3) For the tree layer, the diversity index of marginal green space was highest. Various diversity indexes of the shrub layer were shown as road green space > marginal green area > node green area > waterfront green area. (4) The importance values of shrub species were also used as data sources for the cluster analysis, which, according to appearance and clustering of the sample community, showed 48 sample land communities that could be divided into 13 types. In conclusion, all green space types showed a consistent species diversity trend: shrub > tree > herb. The species richness was low, and the internal structure of the community was single.
To build and optimize the plant landscape with low impact development, plant community characteristics and species diversity in a low-impact development demonstration area, being key to ecological benefits of plant communities, were determined. Taking the plant community in the low-impact development demonstration area of Zhenjiang City as the research object, plant, community quantity characteristics, community structural factors, community diversity, and community clustering were analyzed through typical sample and quantitative analysis methods including a cluster analysis and principal factor analysis. 48 sample plots were set randomly with the 100 m2 standard plot as the main plot, and 204 squares were set in total. Results showed(1) There were 74 families, 147 genera, and 181 species of vascular plants. Pterocarya stenoptera, Cinnamomum camphora, and Koelreuteria integrifoliola were the dominant tree species; Photinia×fraseri, Ligustrum japonicum, and Hypericum monogynum were the dominant shrub species; and Cynodon dactylon, Iris tectorum, and Ophiopogon japonicus were the dominant herb species. (2) The plant community was described by five factors: tree characteristics, ratio of tree to shrub traits, shrub diversity, herb characteristics, and tree diversity. (3) For the tree layer, the diversity index of marginal green space was highest. Various diversity indexes of the shrub layer were shown as road green space > marginal green area > node green area > waterfront green area. (4) The importance values of shrub species were also used as data sources for the cluster analysis, which, according to appearance and clustering of the sample community, showed 48 sample land communities that could be divided into 13 types. In conclusion, all green space types showed a consistent species diversity trend: shrub > tree > herb. The species richness was low, and the internal structure of the community was single.
2019, 36(4): 801-809.
doi: 10.11833/j.issn.2095-0756.2019.04.021
Abstract:
In order to study the adaptability and purification effect on coal mine waste water with different aquatic plants in this paper, using plastic cartons as simulated wetlands, physiological and growth characteristics of five aquatic plants (Triglochin palustre, Scirpus triqueter, Acorus tatarinowii, Typha orientalis, and Phragmites communis) treated with coal mine wastewater and clean water were compared and analyzed by measuring net photosynthetic rate (Pn) and transpiration rate (Tr). The water quality of coal mine wastewater treatment, ck1(static wastewater) and ck2(river sand + static wastewater) were measured monthly to understand the removal effect of the five aquatic plants for chemical oxygen demand (CODCr), total phosphorus (TP), and total nitrogen (TN) in coal mine wastewater. Results showed that net Pn and Tr of T. palustre, A. tatarinowii, and S. triqueter with coal mine wastewater were significantly higher than that of clear water(P < 0.05); whereas, Pn and Tr of T. orientalis and P. communis were not. The relative content of chlorophyll, plant height, and biomass increase of Triglochin palustre and S. triqueter with coal mine wastewater were significantly higher than with clear water(P < 0.05), but T. orientalis, A. tatarinowii, and P. communis were not. Furthermore, results showed that all five species were highly efficient with decreasing concentrations of CODCr from 363 mg·L-1 to 8-18 mg·L-1, TP from 2.07 mg·L-1 to 0.06-0.17 mg·L-1, and TN from 20.00 mg·L-1 to 0.23-0.87 mg·L-1. Thus, adaptability of T. palustr and S. triqueter to coal mine wastewater was stronger, and by comprehensive consideration of removal efficiency and removal rate, T. orientalis, P. communis, and S. triqueter were better than T. palustre and A. tatarinowii.
In order to study the adaptability and purification effect on coal mine waste water with different aquatic plants in this paper, using plastic cartons as simulated wetlands, physiological and growth characteristics of five aquatic plants (Triglochin palustre, Scirpus triqueter, Acorus tatarinowii, Typha orientalis, and Phragmites communis) treated with coal mine wastewater and clean water were compared and analyzed by measuring net photosynthetic rate (Pn) and transpiration rate (Tr). The water quality of coal mine wastewater treatment, ck1(static wastewater) and ck2(river sand + static wastewater) were measured monthly to understand the removal effect of the five aquatic plants for chemical oxygen demand (CODCr), total phosphorus (TP), and total nitrogen (TN) in coal mine wastewater. Results showed that net Pn and Tr of T. palustre, A. tatarinowii, and S. triqueter with coal mine wastewater were significantly higher than that of clear water(P < 0.05); whereas, Pn and Tr of T. orientalis and P. communis were not. The relative content of chlorophyll, plant height, and biomass increase of Triglochin palustre and S. triqueter with coal mine wastewater were significantly higher than with clear water(P < 0.05), but T. orientalis, A. tatarinowii, and P. communis were not. Furthermore, results showed that all five species were highly efficient with decreasing concentrations of CODCr from 363 mg·L-1 to 8-18 mg·L-1, TP from 2.07 mg·L-1 to 0.06-0.17 mg·L-1, and TN from 20.00 mg·L-1 to 0.23-0.87 mg·L-1. Thus, adaptability of T. palustr and S. triqueter to coal mine wastewater was stronger, and by comprehensive consideration of removal efficiency and removal rate, T. orientalis, P. communis, and S. triqueter were better than T. palustre and A. tatarinowii.
2019, 36(4): 810-817.
doi: 10.11833/j.issn.2095-0756.2019.04.022
Abstract:
In the post-G20 period (September 2016 to December 2017), the dominant atmospheric pollutant in winter was PM10 and in summer was tropospheric ozone. For the purpose of better regulating PM10 and ground-level ozone, chemical reactivity of 55 kinds of volatile organic compounds (VOCs) was analyzed at Zhaohui and Xiasha Environmental Monitoring Stations using ozone formation potential (OFP). The third generation atmospheric model WRF-CMAQ developed by the United States Environmental Protection Agency (USEPA) was also used to simulate time-space distributions of PM10 in the city center. Results showed that alkenes were the primary precursor in the downtown area, followed by aromatics, alkanes, and alkynes; whereas, aromatics were the primary precursor in the suburbs, followed by alkenes, alkanes, and alkynes. Ethylene, m/p-xylene, toluene, propylene, and ethylbenzene were ranked as the top five VOCs for OFP in both downtown and suburban areas of Hangzhou. For PM10 in the city center, regional transport of pollutants accounted for about 50% in spring, 32% in summer, 48% in autumn, and 45% in winter. The regional transported PM10 mainly came from the north in spring, autumn, and winter but from the southwest in summer. Local Hangzhou PM10 levels in 2017 included local industry (62.6%), traffic (27.8%), residence (7.3%), and agriculture (2.3%). Consequently, controlling the top five VOC species was the best way to alleviate ground-level ozone, and based on 2016 statistics, shutting down 15% of the local industry and reducing 5% of the local traffic would reduce the annual PM10 level to 70 μg·m-3 meeting the second national environmental air quality standard.
In the post-G20 period (September 2016 to December 2017), the dominant atmospheric pollutant in winter was PM10 and in summer was tropospheric ozone. For the purpose of better regulating PM10 and ground-level ozone, chemical reactivity of 55 kinds of volatile organic compounds (VOCs) was analyzed at Zhaohui and Xiasha Environmental Monitoring Stations using ozone formation potential (OFP). The third generation atmospheric model WRF-CMAQ developed by the United States Environmental Protection Agency (USEPA) was also used to simulate time-space distributions of PM10 in the city center. Results showed that alkenes were the primary precursor in the downtown area, followed by aromatics, alkanes, and alkynes; whereas, aromatics were the primary precursor in the suburbs, followed by alkenes, alkanes, and alkynes. Ethylene, m/p-xylene, toluene, propylene, and ethylbenzene were ranked as the top five VOCs for OFP in both downtown and suburban areas of Hangzhou. For PM10 in the city center, regional transport of pollutants accounted for about 50% in spring, 32% in summer, 48% in autumn, and 45% in winter. The regional transported PM10 mainly came from the north in spring, autumn, and winter but from the southwest in summer. Local Hangzhou PM10 levels in 2017 included local industry (62.6%), traffic (27.8%), residence (7.3%), and agriculture (2.3%). Consequently, controlling the top five VOC species was the best way to alleviate ground-level ozone, and based on 2016 statistics, shutting down 15% of the local industry and reducing 5% of the local traffic would reduce the annual PM10 level to 70 μg·m-3 meeting the second national environmental air quality standard.
2019, 36(4): 818-827.
doi: 10.11833/j.issn.2095-0756.2019.04.023
Abstract:
Forest soil as an important carbon sink plays a critical role in the global carbon cycle and mitigation of climate warming. Fertilization, fire, cutting, understory management an dmulching have changed the productivity of forest ecosystem, which significantly affects the carbon input and carbon output of forest soil. This paper analyzed the effects of different kinds of forest management practices on soil organic carbon pool and proposed important directions for future research, in order to improve the carbon sequestration capacity of plantation soils through forest management practices. Organic fertilizer, organic-inorganic fertilizer and biochar tended to improve the soil active carbon content. N fertilizers reduced the soil active organic carbon content in N-rich forests, but there was an increase or no significant difference in soil active organic carbon content in N-poor forest. The influence of fire on soil organic carbon pool was determined by time length after fire, fire temperature, fire intensity and soil depth. Clear-cut changed the soil temperature, water content and organic matter sources, and thus reduced the organic carbon storage of forest soil. The effect of thinning on soil organic carbon content was related to the harvesting intensity. Understory weeding enhanced soil temperature which could accelerate the decomposition of soil organic carbon, whereas the replacement and addition of understory vegetation would do the other way around. Mulching of organicresidues in forests helped to increase the soil organic carbon content but decreased its stability. With the development of research theory and technology, the impact of forest management practiceson soil carbon form and structure onsoil carbon form and structure will become the main direction for future research.
Forest soil as an important carbon sink plays a critical role in the global carbon cycle and mitigation of climate warming. Fertilization, fire, cutting, understory management an dmulching have changed the productivity of forest ecosystem, which significantly affects the carbon input and carbon output of forest soil. This paper analyzed the effects of different kinds of forest management practices on soil organic carbon pool and proposed important directions for future research, in order to improve the carbon sequestration capacity of plantation soils through forest management practices. Organic fertilizer, organic-inorganic fertilizer and biochar tended to improve the soil active carbon content. N fertilizers reduced the soil active organic carbon content in N-rich forests, but there was an increase or no significant difference in soil active organic carbon content in N-poor forest. The influence of fire on soil organic carbon pool was determined by time length after fire, fire temperature, fire intensity and soil depth. Clear-cut changed the soil temperature, water content and organic matter sources, and thus reduced the organic carbon storage of forest soil. The effect of thinning on soil organic carbon content was related to the harvesting intensity. Understory weeding enhanced soil temperature which could accelerate the decomposition of soil organic carbon, whereas the replacement and addition of understory vegetation would do the other way around. Mulching of organicresidues in forests helped to increase the soil organic carbon content but decreased its stability. With the development of research theory and technology, the impact of forest management practiceson soil carbon form and structure onsoil carbon form and structure will become the main direction for future research.
2019, 36(4): 828-834.
doi: 10.11833/j.issn.2095-0756.2019.04.024
Abstract:
To establish a site index table, an important tool when estimating tree growth and forest productivity, for Betula alnoides plantations, 49 sample plots of B. alnoides plantations were set at all sorts of sites in the Daqing Mountain Forest Area, Guangxi. In each plot, growth performance of all trees was noted, and one average dominate tree was sampled to conduct a stem analysis. Nine equations such as Richards, Weibull, and Korf were used to fit 816 height-diameter data sets obtained from the stem analysis mentioned above, and their statistical indexes including coefficient of determination (R2), absolute mean residual (EAMR), relative mean residual (ERMR), and root mean square error (ERMSE) were calculated for selection of optimal guide curve. Reference age and interval for the site index class were determined by analyzing the growth process of the 49 dominant trees. Afterward a site index table was developed using the standard deviation adjustment method, and it was tested in terms of falling point, fitting significance, and prediction accuracy. Results showed that among the nine models fitted, Richards function performed best with the largest R2 and the smallest EAMR, ERMR, and ERMSE, and was selected as the guide curve. The reference age of B. alnoides was determined as 15 years since the current growth increment and coefficient of variation for dominant heights tended to be stable after 15 years old. Also, the interval of the site index class was two meters based on its fast growth property and range of dominant height (15.2-25.8 m). The site index table developed for plantations of this species indicated that the actual growth process from the falling point test and χ2 test were not significantly different for growth process of dominant height predicted. The estimation error analysis for different aspects of site index and stand age showed that the table had a high forecast accuracy. Thus, this site index table could be applied to site quality evaluation and growth potential prediction for B. alnoides plantations, and it could technically contribute to reasonable plantation management and to matching a site with this species in the Daqing Mountains of Guangxi and regions with similar site conditions.
To establish a site index table, an important tool when estimating tree growth and forest productivity, for Betula alnoides plantations, 49 sample plots of B. alnoides plantations were set at all sorts of sites in the Daqing Mountain Forest Area, Guangxi. In each plot, growth performance of all trees was noted, and one average dominate tree was sampled to conduct a stem analysis. Nine equations such as Richards, Weibull, and Korf were used to fit 816 height-diameter data sets obtained from the stem analysis mentioned above, and their statistical indexes including coefficient of determination (R2), absolute mean residual (EAMR), relative mean residual (ERMR), and root mean square error (ERMSE) were calculated for selection of optimal guide curve. Reference age and interval for the site index class were determined by analyzing the growth process of the 49 dominant trees. Afterward a site index table was developed using the standard deviation adjustment method, and it was tested in terms of falling point, fitting significance, and prediction accuracy. Results showed that among the nine models fitted, Richards function performed best with the largest R2 and the smallest EAMR, ERMR, and ERMSE, and was selected as the guide curve. The reference age of B. alnoides was determined as 15 years since the current growth increment and coefficient of variation for dominant heights tended to be stable after 15 years old. Also, the interval of the site index class was two meters based on its fast growth property and range of dominant height (15.2-25.8 m). The site index table developed for plantations of this species indicated that the actual growth process from the falling point test and χ2 test were not significantly different for growth process of dominant height predicted. The estimation error analysis for different aspects of site index and stand age showed that the table had a high forecast accuracy. Thus, this site index table could be applied to site quality evaluation and growth potential prediction for B. alnoides plantations, and it could technically contribute to reasonable plantation management and to matching a site with this species in the Daqing Mountains of Guangxi and regions with similar site conditions.
2019, 36(4): 835-840.
doi: 10.11833/j.issn.2095-0756.2019.04.025
Abstract:
To determine the allelopathic inhibition of coumarin on Aegilops tauschii and the feasibility of using coumarin as a biological method for invasive plant control, the effects of coumarin with different concentrations (50, 100, 150 mg·L-1) on A. tauschii seed germination and seedling growth were evaluated in a sand-culture experiment. Results showed that compared with a control, the germination rate, germination index, growth of seedling height, and root length were inhibited with increase of coumarin solution treatment. The inhibitory effect of coumarin on the growth of root length was greater than that of seedling height based on the value of the inhibition rate. Only with the 50 mg·L-1 coumarin solution treatment did the relative conductivity and MDA content not increase significantly at 10 d compared with at 5 d (P < 0.05). With the 150 mg·L-1 coumarin solution treatment, the proline content did not increase significantly, and the superoxide dismutase (SOD) activity decreased at 15 d compared with at 10 d. The above results indicated that 150 mg·L-1 coumarin solution had a strong allelopathic and inhibitory effect on seed germination of A. tauschii and could regulate seedling growth of A. tauschii by changing antioxidant enzyme systems, cell membrane permeability, and membrane lipid peroxidation.
To determine the allelopathic inhibition of coumarin on Aegilops tauschii and the feasibility of using coumarin as a biological method for invasive plant control, the effects of coumarin with different concentrations (50, 100, 150 mg·L-1) on A. tauschii seed germination and seedling growth were evaluated in a sand-culture experiment. Results showed that compared with a control, the germination rate, germination index, growth of seedling height, and root length were inhibited with increase of coumarin solution treatment. The inhibitory effect of coumarin on the growth of root length was greater than that of seedling height based on the value of the inhibition rate. Only with the 50 mg·L-1 coumarin solution treatment did the relative conductivity and MDA content not increase significantly at 10 d compared with at 5 d (P < 0.05). With the 150 mg·L-1 coumarin solution treatment, the proline content did not increase significantly, and the superoxide dismutase (SOD) activity decreased at 15 d compared with at 10 d. The above results indicated that 150 mg·L-1 coumarin solution had a strong allelopathic and inhibitory effect on seed germination of A. tauschii and could regulate seedling growth of A. tauschii by changing antioxidant enzyme systems, cell membrane permeability, and membrane lipid peroxidation.
