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Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes/issues, but are citable by Digital Object Identifier (DOI).
Temporal and spatial dynamic monitoring of land desertification and landscape pattern evolution characteristics in the Xiaoluan River Basin
LI Jiahao, LIU Yuguo, ZHAO Ziqing, ZHOU Yining, XU Zihan, CHEN Xinjun, CUI Ming
, Available online  doi: 10.11833/j.issn.2095-0756.20220731
  Objective  This study, with an investigation of the process of land desertification changes in the Xiaoluanhe River Basin in Weichang Manchu and Mongolian Autonomous County (Weichang County) of Hebei Province, a typical agricultural-pastoral interlacing zone suffering from a serious problem of land desertification, is aimed to understand the influence of land use changes and elevation on land desertification so as to provide a theoretical basis for the prevention and control of land desertification in the basin and the comprehensive management of mountains, water, forests, lakes, grasses and sands.   Method  First, Google Earth Engine and ArcGIS platform was utilized to analyse the Landsat series remote sensing data in 2000, 2010 and 2020. Then, the normalized vegetation index (NDVI) and surface albedo feature space were constructed to establish the desertification difference index (DDI) model and classify the sandy land in the degree of desertification.   Result  The past 20 years has witnessed an overall improvement trend in the land of Xiaoluanhe River Basin with the land area of extremely severe and severe desertification decreased by nearly 80% and 56% respectively and light desertification and non-desertification land accounting for about 65% of the basin area. The improvement rate of desertification land decreased in the later stage, and the improved area was concentrated in Saihanba Forest Farm and the lower reaches of Xiaoluanhe River. The desertification landscape in the river basin tended to be concentrated with the degree of landscape fragmentation continuing to decrease. There was an obvious improvement on the desertification for woodland and grassland and the desertification tended to decrease with the increase of altitude.   Conclusion  Since 2000, the land in the Xiaoluanhe River Basin has improved as a whole in terms of desertification whereas there is a trend of deterioration of land in areas such as the town of Yudaokou and the pastures. Therefore, it is necessary to strengthen measures in the conduct of precision sand control so as to deal with the desertification in the river basin and eventually realize the sustainable development of the Xiaoluanhe River Basin. [Ch, 6 fig. 4 tab. 34 ref.]
Microstructure and humidity response of polyethylene glycol/cellulose nanocrystal composite liquid crystal films
XU Yunzhe, CHEN Yifan, LIN Xinyi, FANG Xinye, WU Qiang
, Available online  doi: 10.11833/j.issn.2095-0756.20230236
  Objective  Cellulose nanocrystalline (CNC) liquid crystal film, as a kind of photonic crystal with special optical properties, has a promising prospect in the fields of anti-counterfeiting technology, photoelectric functional materials and humidity responsive functional materials. This study, with an exploration of the influence of polyethylene glycol (PEG) on the humidity response of CNC liquid crystal films, is aimed to explain its response mechanism to provide a theoretical basis for the development of low-cost, reusable and highly sensitive PEG/CNC composite film humidity sensors.   Method  The chiral nematic photonic liquid crystal films with humidity response were prepared by evaporation-induced self-assembly of PEG/CNC suspension, and the effects of PEG content on the microstructure, color evolution, mechanical properties and humidity response of the PEG/CNC films were investigated. Then, the cyclic properties of PEG/CNC liquid crystal films under different humidity conditions were studied.  Result  For pure CNC film system, with the increase of CNC content from 3% to 7%, the pitch of CNC liquid crystal film decreased, and the maximum wavelength of reflected light shifted from 596.5 nm to 511.0 nm. For PEG/CNC films, with the increase of PEG content, the pitch of PEG/CNC composite liquid crystal film decreased from 394.0 nm to 244.0 nm while the maximum wavelength of reflected light moved from 613.5 nm to 350.5 nm. The toughness increased first and then decreased, the optimal PEG addition amount was 5%, the breaking energy was 31.9 J·m−2 which was 138% higher than that of pure CNC film. After 5 hygroscopic and dehumidifying experiments, the PEG/CNC film showed good humidity response repeatability with the change rate of the equilibrium wavelength being lower than 0.6%.  Conclusion  An iridescent photonic PEG/CNC liquid crystal film for humidity sensing were prepared, and it was found that PEG can regulate the structural colour by modulate the pitch of the composite film. [Ch, 6 fig. 25 ref.]
Approaches and policy recommendations for reducing emissions and increasing carbon sinks in crop industry under the background of carbon peak and carbon neutrality
KONG Delei, JIANG Peikun
, Available online  doi: 10.11833/j.issn.2095-0756.20220742
Carbon peak and carbon neutrality (dual carbon) is a broad and profound systemic change that requires the participation of various industry sectors. Unlike other industries, crop industry is not only an important source of greenhouse gas emissions, but also has enormous potential for carbon sequestration. Promoting emission reduction and carbon sequestration in crop industry is an indispensable part of achieving national dual carbon. In this paper, the main emission sources of nitrous oxide (N2O) and methane (CH4) in the field of planting were sorted out, including N2O emissions caused by excessive nitrogen application, water-saving irrigation of rice fields, and livestock and poultry waste, as well as CH4 emissions from flooded rice fields and ruminant animals. In addition to the direct emissions mentioned above, there existed a significant amount of indirect carbon emissions during agricultural production processes. The greenhouse gas emission reduction and carbon sequestration potential of crop industry were analyzed and the main emission reduction and sequestration pathways were summarized, including N2O emission reduction in dryland, CH4 emission reduction in rice fields. The potential of carbon sequestration and sink enhancement in crop industry could be increased through the application of organic fertilizer, straw return to the field, conservation tillage and return of farming waste to the field through pyrolysis and charring. This paper also discusses the feasibility and importance of carbon labeling and carbon trading in promoting green and low carbon development in China’s crop industry. It is clarified that emission reduction and soil carbon sink increase in crop industry must be based on the premise of safeguarding food security, avoiding blind emission reduction and excessive emission reduction, and must be coordinated with green development of crop industry. A sound guarantee and innovation system should be established to provide assistance for China’s carbon peak and carbon neutrality. [49 ref.]
Remote sensing monitoring of subtropical forest disturbance and restoration in Songyang County, Zhejiang Province
ZOU Weimin, DING Jun, HUANG Zihao, HUANG Lei, SONG Meixuan, LI Xuejian, DU Huaqiang
, Available online  doi: 10.11833/j.issn.2095-0756.20230324
  Objective  Songyang County in Zhejiang Province is rich in forest resources and has great potential for carbon sinks, and is a tertiary linkage area of Baishanzu National Park. This study aims to monitor forest disturbance and restoration in Songyang County, so as to provide an important reference for forest management in this region and ecological protection for Baishanzu National Park.   Method  Using the LandTrendr algorithm of the Google Earth Engine (GEE) cloud platform, as well as Landsat satellite remote sensing time series data from 1987 to 2020, the forest disturbance and restoration status in Songyang County, Zhejiang Province from 1987 to 2020 were detected, and the spatial and temporal characteristics of forest disturbance and restoration were analyzed.   Result  (1) The overall accuracy of the LandTrendr algorithm in detecting forest disturbance and restoration reached 82%, and the production accuracyand user accuracy of forest disturbance and restoration were both higher than 80%, indicating that the monitoring of forest disturbance and restoration in Songyang County was effective. (2) The total area of forest disturbance and restoration in Songyang County reached 148.14 and 236.86 km2, accounting for 12.74% and 20.37% of the forest land area, indicating a net increase in forest area in Songyang County from 1987 to 2020. (3) Forest changes in Dadongba Township, Banqiao She Township, Xinxing Township and Yuyan Township in Songyang County were relatively frequent, and the area of forest disturbance and restoration was higher than that in other townships. In particular, the forest area of Dadongba Township changed the most, with an increase of 20.04 km2.  Conclusion  The LandTrendr algorithm based on the GEE cloud platform has achieved precise monitoring of forest disturbance in this county. The overall forest area in Songyang County has shown an increasing trend in the past 30 years. [Ch. 3 fig. 3 tab. 46 ref.]
Fertility effect of E3 ubiquitin ligase gene CsRNF217 in transgenic tobacco (Nicotiana tabacum) plants
YE Xiaoling, ZHAO Yuhong, JIANG Nan, ZHANG Min, ZHANG Chi
, Available online  doi: 10.11833/j.issn.2095-0756.20220710
  Objective  This study, with an investigation into the transgenic plants of tobacco (Nicotiana tabacum) overexpressing CsRNF217, is aimed to verify the effect of the E3 ubiquitin ligase gene CsRNF217 on male sterility.   Method  First, an analysis was conducted of the pollen viability of wild type (WT) and the positive plants of the 1st generation of selfing of transgenic plants (T1) with the employment Alexander staining and pollen germination in vitro. Then, the seed setting rate was obtained via selfing and reciprocal crosses between transgenic plants and WT. Finally, semi-quantitative Reverse Transcription Polymerase Chain Reaction (RT-PCR) was used to analyze the relative expression of CsRNF217 in T1 positive tobacco plants.   Result  CsRNF217 derived from Citrus suavissima ‘Wuzi Ougan’ was efficiently expressed in T1 lines. The pollen dyeing viability and in vitro germination rate of T1 lines, selfing seed setting rate of T1 lines, and seed setting rate of T1 lines reciprocal crosses with WT were significantly lower than those of WT (P<0.05).   Conclusion  T1 plants overexpressing CsRNF217 had a severe decline in pollen fertility and partial aberrant of embryo sac, suggesting that an up-regulation of CsRNF217 could play a negative regulatory role on male and female fertility in transgenic tobacco plants. [Ch. 5 fig. 3 tab. 22 ref.]
Response of grassland soil CO2 emissions to urine addition under different sterilization methods
JIANG Shuzhen, LIAN Yichen, HUA Runxin, ZHANG Yuhan, JIANG Wenting, XIAO Xiangqian, FAN Bo, CAI Yanjiang
, Available online  doi: 10.11833/j.issn.2095-0756.20230149
  Objective  This study, with an investigation of the variations of biotic and abiotic processes driving soil organic carbon (SOC) mineralization affected by livestock excreta deposition in grazing grassland ecosystems, is aimed to provide new insights into better understanding of the response and feedback of soil carbon pool changes induced by anthropogenic activities to global climate change.   Method  In this study, SOC mineralization rates (as indicated by CO2 emission rates) were measured of the soil of an alpine meadow added with different rates of urine (0, 250, 500, 750, 1 000 kg·hm−2·a−1) under different sterilization circumstances (no sterilization, autoclaving sterilization, chloroform fumigation sterilization), while the soil pH, dissolved organic carbon (DOC), total dissolved nitrogen (TDN), soil organic carbon (SOC), total nitrogen (TN), ammonium nitrogen (NH4 +-N), nitrate nitrogen (NO3 -N) concentration were simultaneously determined, so as to explore the differences in the response of biotic and abiotic SOC mineralization processes to urine addition.   Result  (1) The addition of urine promoted CO2 emissions, which increased with the increase in the amount of urine added under different sterilization methods, demonstrating a positive correlation between soil CO2 emissions and soil pH and NH4 +-N concentrations (P<0.05). (2) Soil CO2 emission was inhibited by sterilization, and the inhibition effect of autoclaving sterilization on soil CO2 emission was significantly higher than that of chloroform fumigation sterilization (P<0.05). (3) The CO2 emission from biotic and abiotic processes both increased with the increase of urine addition rate, with the contribution of biotic process to soil CO2 emission being greater than that of abiotic process.   Conclusion  Urine deposition can promote soil CO2 emission from biotic and abiotic processes, with more contribution from the biotic process, however, the contribution of abiotic SOC mineralization to soil CO2 emission should not be neglected. [Ch, 5 fig. 1 tab. 42 ref.]
Effect of foliar fertilization on seed quality of Torreya grandis ‘Merrillii’ during seed filling period
HAO Qichun, XIE Jiquan, DAI Wensheng, LI Keyu, YU Chenliang, YU Weiwu
, Available online  doi: 10.11833/j.issn.2095-0756.20230194
  Objective  This study aims to explore aspects of Torreya grandis ‘Merrillii’ seeds, including appearance, nutritional quality, element content, flower bud differentiation, and expansion and fruit setting, so as to provide a theoretical basis for supplementing tree nutrition and improving seed quality.   Method  During the seed filling period of T. grandis ‘Merrillii’ from June to August, the seeds were treated with water as a control and sprayed with 7 commercial foliar fertilizers (amino acid water-soluble fertilizer, fulvic acid water-soluble fertilizer, active potassium water-soluble fertilizer, high-strength calcium water-soluble fertilizer, liquid boron water-soluble fertilizer, trace element water-soluble fertilizer, and macro-element water-soluble fertilizer). Physiological indicators of seeds in terms of seed morphology, oil content and fatty acid composition, crude protein content, starch content, soluble sugar content, and flowering intensity were measured and their effects on seed quality were analyzed.   Result  Spraying amino acid water-soluble fertilizer and macro-element water-soluble fertilizer significantly increased (P<0.05) the kernel shape index, single kernel mass, nucleation rate, kernel type index, and single kernel mass of seeds, as well as oil content, soluble sugar content, and flowering intensity, and significantly reduced starch content. Among them, the single kernel mass of seeds treated with amino acid water-soluble fertilizer increased by 9.8% compared with the control, while the starch content decreased by 1.9%. The single kernel mass, oil content, and soluble sugar content of seeds treated with macro-element water-soluble fertilizer increased by 9.5%, 11.9%, and 15.9%, respectively, compared with the control. At the same time, spraying amino acid water-soluble fertilizer significantly promoted (P<0.05) the content of taxoleic acid in seeds, which increased by 15.9% compared with the control, while spraying macro-element water-soluble fertilizer significantly (P<0.05) increased the content of unsaturated fatty acids in seeds by 4.2% compared with the control. In addition, high-strength calcium water-soluble fertilizer had a significant promoting effect (P<0.05) on the increase of kernel yield, flowering intensity, and fruit setting rate, which were 3.3%, 17.1%, and 10.9% higher than the control. The active potassium water-soluble fertilizer significantly increased the protein content of seeds by 13.6% compared with the control. Principal component analysis showed that the comprehensive quality score of seeds treated with amino acid water-soluble fertilizer was the highest.   Conclusion  The amino acid water-soluble fertilizer treatment has the best effect, followed by high-strength calcium water-soluble fertilizer and macro-element water-soluble fertilizer. [Ch. 3 fig. 5 tab. 29 ref.]
Dust retention capacity and leaf physiology and photosynthesis response of 7 garden plants in Zhengzhou City
HE Dan, LI Haitao, YUAN Jiangqin, WANG Anyin, WANG Yifei, LI Yonghua, LIU Yiping
, Available online  doi: 10.11833/j.issn.2095-0756.20230160
  Objective  The objective is to investigate the dust retention and comprehensive anti-pollution capacity of typical garden plants in Zhengzhou.  Method  7 common garden plants (Ligustrum lucidum, Eriobotrya japonica, Photinia serrulata, Fatsia japonica, Euonymus japonicus, Pittosporum tobira, and Nandina domestica) were selected as the objects, and 3 sampling areas of streets, campuses and parks were set up. Atmospheric particulate matter with different particle sizes (total suspended particulate, inhalable particulate matter, fine particulate matter) retained by each plant leaf was collected. The dust retention per unit leaf area of each plant was determined by the method of graded membrane filtration. At the same time, the photosynthetic parameters and leaf physiological indicators of the plants under different pollution levels were compared. The correlation and principal component analysis of plant dust retention and physiological photosynthetic indexes were carried out, and garden plants with outstanding dust retention and comprehensive anti-pollution ability were screened.   Result  (1)The amount of dust retention per unit leaf area of plants was proportional to the mass concentration of atmospheric particulate matter in the environment. The increase in particulate matter retention by different plants was uneven with the aggravation of particulate matter pollution. (2)With the increase in atmospheric particulate matter concentration, the net photosynthetic rate, stomatal conductance, chlorophyll a and b content of leaves decreased, while the malondialdehyde content and superoxide dismutase and peroxidase activities of leaves increased. (3)The results of principal component analysis showed that the comprehensive ability of dust retention and anti-pollution of P. tobira and F. japonica was more prominent.  Conclusion  In the future control of urban dust pollution and urban greening construction in Zhengzhou, P. tobira and F. japonica can be selected as priority plants. [Ch, 2 fig. 4 tab. 38 ref.]
Generation and application of a fluorescent probe for phosphatidic acid in Arabidopsis thaliana
MA Shuyan, ZHENG Yueping, ZHENG Zhifu
, Available online  doi: 10.11833/j.issn.2095-0756.20230355
  Objective  Phosphatidic acid (PA) serves as an important signal molecule involved in the regulation of plant growth and development and different responses to various stresses as well as a general precursor for glycerolipid biosynthesis. However, little is known thus far about the dynamic changes of PA in plant cells. This study attempted to construct a fluorescent probe that can effectively monitor the changes of PA in plant cells and use it to measure the changes of intracellular PA under saline-alkaline stresses.   Method  The corresponding nucleotide sequence for PA-specific binding domain within the Spo20p protein was fused to the green fluorescent protein gene. Transgenic Arabidopsis thaliana lines bearing the fusion gene under the control of the constitutive promoter UBQ10 was then generated via genetic transformation. The resulting fusion protein constituted a fluorescent probe specifically binding to PA. Subsequently, this probe was employed to monitor the changes of cellular PA under saline-alkaline stresses.   Result  Seven transgenic A. thaliana lines homozygous for single transfered DNA(T-DNA) insertion of the fusion gene was generated. Real time quantitative PCR(RT-qPCR) analysis showed that expression levels of the fusion gene varied among different lines. Experiments with various exogeneous PA concentrations revealed that as the expression level of the PA probe increased, it could effectively monitor the changes of cellular PA in the root tips treated with 2 μmol·L−1 exogenous PA for 10 min, whereas this was not the case when the expression level of the probe was low, indicating that the sensitivity of the probe for PA detection is, to a certain degree, associated with its expression level. Based on this fluorescent PA probe, PA accumulation at the plasma membrane or in the intracellular space was evident in the root tips under saline-alkaline stresses for 5 min, implying that PA may play important roles in early plant responses to saline-alkaline stresses.   Conclusion  A fluorescence probe for effective monitoring of cellular PA was developed in this study. This probe can monitor the alterations in cellular PA level during early plant responses to saline-alkaline stresses, thereby providing a new tool to study early responses to various stresses. [Ch, 7 fig. 1 tab. 36 ref.]
Scenario simulation and prediction of Qinhu National Wetland Park based on PLUS Model
WANG Hui, LIU Yuan, SHI Yan, DING Zhifan, JIANG Hongchao
, Available online  doi: 10.11833/j.issn.2095-0756.20230163
  Objective  This study aims to explore the scenario plan for promoting the sustainable development of Qinhu National Wetland Park in Jiangsu Province.   Method  Taking Qinhu National Wetland Park as an example, according to the construction goal and upper level planning of the research area, three scenarios were constructed: natural development, ecological protection and tourism development. Based on the simulation results of PLUS model, an optimization scenario was constructed.   Result  (1) From 2015 to 2020, the conversion of shrub land and construction land in the study area increased the most, which was 14.88% and 8.77% respectively, while the conversion of grassland decreased the most, which was −33.25%. The area of arbor forest land, lake wetland, river wetland, marsh wetland and cultivated land was relatively stable. (2) The land use changes under the three scenarios showed different trends. Under the scenarios of natural development and tourism development, the construction land expanded greatly in the east, middle and southwest of the study area, while the shrub land increased more significantly under the natural development scenario. Under the ecological protection scenario, the central lake wetland and the eastern river wetland showed an expanding trend, and the construction land and cultivated land were the main sources. (3) Under the optimization scenario, various wetlands showed an expanding trend, totaling 69.05%. Arbor forest and shrub land accounted for 16.19% and 5.57% respectively, and the construction land area accounted for 5.90%.   Conclusion  Construction land under natural development and tourism development scenarios encroaches on all kinds of wetlands and forestland, while the area of all kinds of wetlands and forestland under ecological protection scenario increases effectively, and construction land is not fully utilized. Under the optimization scenario, all land use types are reasonably regulated, which helps to coordinate the dual goals of ecological protection and rational development in the study area. [Ch. 6 fig. 5 tab. 30 ref.]
Undergrowth plant diversity in the northern part of secondary forest in Hanshan Mountain, Inner Mongolia
ZHAO Pengwu, GUAN Lijuan, ZHOU Mei, SHU Yang, WU Yiheng, CHEN Jiajia
, Available online  doi: 10.11833/j.issn.2095-0756.20230204
  Objective  Qingshan Reserve is a typical area in the northern section of the secondary forest in Hanshan, Inner Mongolia, in order to understand the characteristics of plant diversity under the forest death gradient in the northern section of the Hanshan secondary forest in Inner Mongolia, and to provide a basis for scientific protection and utilization of forest autogenous plant communities and explore plant communities more suitable for forest development.   Method  Taking the secondary forest of Populus davidiana in Qingshan Reserve as the research object, the plant composition of different dead gradients was investigated by sample survey method, and the differences in plant composition and diversity were analyzed by using biodiversity index and community similarity coefficient.  Result  There were 45 plant species in the northern section of Hanshan secondary forest area, Inner Mongolia, including 9 species of trees, 5 species of shrubs and 31 species of herbs, and the number of plant species in the sample plot was as follows: mild death plot>severe death plot>moderate death plot. The Simpson and Shannon-Wiener indices in the same field showed mildly dead stands>severely dead stands>moderately dead stands. Moderately dead plots had the highest richness and Pielou uniformity index. The greatest variation in communities within mildly fatal plots was found by PCoA analysis. The SI index was in the range of 55%−61%, there were 13 species in different death gradient forest stands, the difference between the relative coefficient of the tree layer and the shrub layer was not large, and the reduction benefit of herbaceous diversity was obvious, resulting in the difference of SI index of different death gradient forest stands became larger, and overall, with the increase of aspen mortality degree, the difference in vegetation composition also increased.  Conclusion  The mass forest mortality inhibits the development of herbaceous plant diversity, but promotes the renewal of trees and shrubs. The dominance of aspen in the study area declined, and whether the diversity of forest renewal could form mixed forests needed to be further studied.[Ch, 4 fig. 3 tab. 26 ref.]
Spatial pattern and impact mechanism of national forest villages in Jiangxi Province
LI Zimo
, Available online  doi: 10.11833/j.issn.2095-0756.20230148
  Objective  Explore the spatial pattern and impact mechanism of national forest villiages is helpful for rural greening, beautification, and optimization.   Method  Taking 430 national forest villages in Jiangxi as the research object, a four-dimensional structure system of “evaluation-analysis-index-data” was constructed, and the spatial pattern and its formation mechanism were discussed by comprehensively using GIS spatial analysis, Geographical detectors and Geographical weighted regression.   Result  (1) The national forest villages in Jiangxi exhibit a low land oriented terrain pattern, a geopolitical pattern at the edge of the provincial boundary, an administrative pattern that emphasizes minority administrative regions, and an economic pattern that deviates from the economic center. (2) The explanatory power of forest vegetation and ecological environment in natural environmental factors on the formation of national forest villages spatial pattern is significantly better than that of geographical environmental indicators; The tourism resources in social environmental factors have a stronger explanatory power on the formation of the national forest villages spatial pattern. (3) From the perspective of spatial pattern, the dominant areas of the main influencing factors are mainly distributed in the marginal areas of the provincial boundary, especially in the northern-northeastern Jiangxi or southern-southwestern Jiangxi regions; From the perspective of regression coefficients, the main influencing factors have a positive and negative relationship with the formation of the national forest rural spatial pattern, showing a comprehensive impact effect.   Conclusion  There is spatial coupling between environmental factors such as biological abundance, vegetation index, and the distribution of national forests villiages, but the impact varies significantly, reflecting the coexistence of commonality and individuality at different spatial scales, and possessing a certain value of “correction”. [Ch, 4 fig. 2 tab. 19 ref.]
Compressive strength of small-diameter bamboo and its influencing factors
DAI Fukuan, WANG Ziwei, WANG Hankun, TIAN Genlin, WANG Chuangui
, Available online  doi: 10.11833/j.issn.2095-0756.20230207
  Objective  This study is aimed to investigate the testing method for determining the compressive strength of small-diameter bamboo culms as well as the impact of fiber sheath volume fraction and distribution density of vascular bundles on it.   Method  Four species of small-diameter bamboo, namely Pleioblastus amarus, Phyllostachys nidularia, Phyllostachys heteroclada, and Phyllostachys propinqua, with a diameter at breast height of less than 50 mm, were selected as research subjects before bamboo culm samples were utilized to investigate the compressive strength testing method for small-diameter bamboo and to examine the impact of varying length-to-diameter ratios on compressive strength. At the same time, a bamboo vascular bundle detection model based on the YOLO deep learning algorithm was employed to determine the number of vascular bundles and fiber sheath area so as to investigate their influence on compressive strength.   Result  (1) there were no significant differences in the test results among specimens with different length-to-diameter ratios and the test results for the specimen with a length-to-diameter ratio of 2.0 were more reasonable. (2) Of specimens at the length-to-diameter ratio of 2.0, Phyllostachys propinqua exhibited the highest compressive strength at 82.91 MPa while Phyllostachys heteroclada demonstrated the lowest strength at 67.01 MPa. (3) The volume fraction of fiber sheath was highest in Phyllostachys nidularia at 35.64% and lowest in Phyllostachys heteroclada at 33.05%. (4) The density of vascular bundles in Pleioblastus amarus was highest at 7.94 pcs·mm−2, while that of Phyllostachys propinqua was the lowest at 5.77 pcs·mm−2. (5) Studies that treated various species of bamboo as a unified entity have shown that the positive effect of the volume fraction of fiber sheath on compressive strength was significant while the influence of vascular bundle distribution density on compressive strength was relatively minor.   Conclusion  A specimen with a length-to-diameter ratio of 2.0 is an ideal choice for testing the compressive strength of small-diameter bamboo and the specimen should be controlled for a period of (90±30) seconds before it collapses. Furthermore, the small-diameter bamboo selected for this experiment exhibited excellent compressive performance while there was a direct correlation between the volume fraction of fiber sheath (y) and compressive strength (x), as shown in the equation y=260.44x−18.26. [Ch, 4 fig. 2 tab. 33 ref.]
Using volume and volume increment as units of payment for ecosystem services based on ecological public forest
MA Haoran
, Available online  doi: 10.11833/j.issn.2095-0756.20230026
  Objective  Transforming the unit of forest payments for ecosystem services is the requirement for promoting the quality of ecological public forests and stimulating the enhancement of forest ecological services. There is an urgent demand for the theory and academic aspects to improve the method of payments funds allocation scientifically through diversified units of forest payments for ecosystem services, which can evaluate the ecological service value of ecological public forests differentiated and reasonably.   Method  Based on the scope and characteristic of forest ecosystems accumulation and increment, we explored diversified units of payments for ecosystem services, and propose the idea that forest ecosystems accumulation compensation in terms of volume unit which can promote “compensation by quality” for forest ecological benefits, and “incentive” compensation in terms of volume increment unit which can promote the enhancement of forest carbon sink capacity. Taking the ecological public forest in Linqi Town, Chun’an County, Zhejiang Province as a case, this paper analyzed and evaluated the feasibility of ecological public forest payments funds allocation using volume unit and volume increment unit based on the smallest forest division unit - small class.   Result  Using volume as unit of ecological public forest payments is more effective than that of area, which could highlight the differentiation of forest water-holding function and forest quality.   Conclusion  Implementing payments of ecological public forests using volume unit combined with volume increment unit could effectively maintain the existing forest ecosystem stock and stimulate the of forest ecosystem increment, which can make up for the inability of area unit on value incentive and dynamics in the current payments for public forest ecosystem services, and point out the direction of improvement for forest management to effectively promote ecological services. [Ch, 4 fig. 4 tab. 28 ref.]
Analysis and evaluation of flower and fruit characteristics of different Prunus mume cultivars
WANG Shuang, DONG Bin, WANG Yiguang, ZHAO Hongbo
, Available online  doi: 10.11833/j.issn.2095-0756.20230213
  Objective  Prunus mume is an ornament and fruit plant widely cultivated in China. The aim of this study is to select and evaluate P. mume cultivars with both flower and fruit functions, so as to provide basis for fruit processing and utilization.   Method  28 P. mume cultivars were selected as research object. Flower traits, fruiting capacity, fruit quality indexes were measured and evaluated by principal component analysis and cluster analysis.   Result  The flower diameter of 28 P. mume cultivars ranged from 19.14 to 31.38 mm, with 5-23 petals. White P. mume cultivars accounted for the largest proportion. There were significant differences in fruit setting among P. mume cultivars, with ‘Lijiang Zhaoshui’, ‘Yulong Hongfei’ and Yulong Feixue’ being more prone to fruit setting. In addition, there were differences in fruit appearance and internal quality among different P. mume cultivars. Principal component analysis was conducted on 28 cultivars, and 16 indexes were simplified into 4 common factors, with a variance explanation percentage of 82.72%. The comprehensive scores showed that ‘Die Yuchong’, ‘Gu Lihong’, ‘Danfen Chuizhi’, ‘Hongyan Zhusha’, ‘ZAFU-CZ02’, ‘Jiangmei’ and ‘Lijiang Zhaoshui’ had higher scores. Cluster analysis showed that when the Euclidean distance was 24, P mume cultivars could be divided into 6 groups. Based on the results of principal component and cluster analysis, 4 excellent varieties for both flower and fruit use were selected, including ‘Danfen Chuizhi’, ‘Lijiang Zhaoshui’, ‘Gu Lihong’, and ‘Hongyan Zhusha’.   Conclusion  There are differences in flower traits, fruit setting and fruit quality among different P. mume cultivars. According to the comprehensive characteristics of the flower, fruit yield, and fruit quality, it can be concluded that ‘Danfen Chuizhi’ and ‘Lijiang Zhaoshui’ are easy to bear fruit and have the best comprehensive fruit quality. They are excellent P. mume cultivars suitable for both flower and fruit. ‘Gu Lihong’ and ‘Hongyan Zhusha’ have bright flower color, with semi double petals and easy to bear fruit. They are P. mume cultivars suitable for flower and fruit production. [Ch, 6 fig. 6 tab. 30 ref.]
Pinus yunnanensis volume estimation model based on UAV multispectral image
DENG Zaichun, ZHANG Chao, ZHU Xiali, FAN Jinming, QIAN Hui, LI Chengrong
, Available online  doi: 10.11833/j.issn.2095-0756.20230263
  Objective  Unmanned aerial vehicle (UAV) multispectral remote sensing images, with richer spectral information than visible light images, have great potential in forest volume estimation. Taking UAV-borne multispectral remote sensing images as the main data source, this study aims to explore the remote sensing estimation model of forest volume, so as to overcome the drawbacks of traditional ground survey, such as heavy workload, long time consumption and high cost.  Method  Taking the typical natural pure Pinus yunnanensis forest in Luomian Township, Fumin County, Kunming City as the research object, the single-band reflectance, vegetation index and texture feature were extracted according to the UAV multispectral image, and the standard ground mean of each characteristic variable was calculated. The characteristic variables significantly correlated with the forest volume were screened, and the forest volume estimation model was established using multiple linear regression, random forest and support vector machine. The model accuracy was evaluated by coefficient of determination (R2), root mean square error (ERMS), mean absolute error (EMA) and mean relative error (EMR).   Result  (1) Among the three models, the random forest had the highest accuracy (R2=0.89, EMA=4.69 m3·hm−2, ERMS=5.45 m3·hm−2, EMR=14.5%), followed by the support vector machine (R2=0.74, EMA=5.27 m3·hm−2, ERMS=8.31 m3·hm−2, EMR=13.1%). The multiple linear regression model had the minimum accuracy (R2=0.35, EMA=10.12 m3·hm−2, ERMS=12.85 m3·hm−2, EMR=28.1%). The estimation accuracy of the three models in the test set decreased. The random forest had the best performance, followed by the support vector machine, and the multivariate linearity was the worst. (2) The three models had certain underestimation and overestimation in the estimation of P. yunnanensis forest volume. (3) Texture feature was still an important factor that could not be ignored in estimating the forest volume of P. yunnanensis based on UAV multispectral images.   Conclusion  Based on the multi-spectral images of UAV, the single-band reflectance, vegetation index, and texture factor mean values of the standard ground were extracted without individual tree segmentation, and the variables suitable for volume estimation were screened to construct an estimation model. Through the precision evaluation of the three models, the random forest is the best model for estimating P. yunnanensis volume. [Ch, 2 fig. 5 tab. 27 ref.]
Design and analysis of bamboo cableway skidding transportation equipment sports car and suspension cable
LEI Yongjie, ZHOU Jianbo, FU Wansi, FENG Haiyun, FU Xing, WANG Fanyu, ZHANG Lizhong, ZHANG Yuqing, LIAO Xinhua
, Available online  doi: 10.11833/j.issn.2095-0756.20230141
  Objective  In response to the difficulties in transporting bamboo down the mountain after logging, the unstable effect of current simple cable type mechanical equipment, the insufficient endurance of transportation sports cars, and the lack of safety assurance, this study aims to design a bamboo cableway skidding sports car transportation system, so as to achieve safe and efficient transportation of bamboo down the mountain.   Method  Through research on bamboo forest farms in Fujian, Hunan Provinces with abundant bamboo resources, the basic design parameters of the bamboo cableway skidding and sports car transportation system were determined. The overall functions, dimensions, and key components of the suspension cable and sports car were designed. The main load-bearing components of the sports car were analyzed by finite element analysis, and the strength and stiffness of the sports car were verified. The coupling vibration of cableway sports car system was analyzed by ADAMS software, and the main influencing factors in transporting bamboo by cableway were determined. Taking transportation speed, the total weight of sports cars and bamboo, and the inclination angle of the cableway as evaluation factors, and comprehensive evaluation of the safety and efficiency of sports car transportation of bamboo as indicators, Box-Behnken simulation experiments were conducted to optimize parameter combination.   Result  The results of the quadratic regression orthogonal rotation combination experiment indicated that the three factors which had significant impact on the safety and efficiency of sports car transportation in descending order were cableway inclination angle, transportation speed, and total weight of sports car and bamboo. When the transportation speed was 3.95 m·s−1, the total weight of the sports car and bamboo was 576.67 kg, and the inclination angle of the cableway was 17.09°, the comprehensive transportation safety and efficiency reached the best.   Conclusion  The transportation safety and efficiency are good when the inclination angle of the carrying cable is 16.50°−20.40°, the transportation speed is 3.00−4.00 m·s−1, and the total weight of the sports car and bamboo is 420.00−580.00 kg. It can achieve charging and energy storage during the bamboo cableway skidding transportation operation, and ensure the safe and efficient transportation of bamboo down the mountain.[Ch, 6 fig. 5 tab. 13 ref.]
Chemical components of Rhexocercosporidium panacis from Panax ginseng
LIU Peng, LI Qi, YANG Jian, SUN Di’ an, KUANG Yi, DING Gang
, Available online  doi: 10.11833/j.issn.2095-0756.20230150
  Objective  The aim is to study the secondary metabolites of Rhexocercosporidium panacis, so as to discover new active compounds and to provide a chemical basis for later research on the pathogenesis of R. panacis.   Method  The crude extracts of R. panacis were obtained through solid fermentation of rice, and purified by silica gel column chromatography, reversed silica gel column chromatography (ODS), Sephadex LH-20, and semi-preparative liquid chromatography to gain monomeric compounds. The structure of monomeric compounds was identified based on mass spectrometry, nuclear magnetic resonance spectroscopy, and literature data comparison. The antioxidant activities of 9 compounds were tested by DPPH radical scavenging method and the preliminary phytotoxic activity of compounds 4~9 was evaluated.   Result  9 compounds were isolated from R. panacis, including three sterols: ergosterol (1), 5,8-epidioxy-5α,8α-ergosta-6,9,22E-tien-3β-ol (2), and 5,8-epidioxy-5α,8α-ergosta-6,22E-dien-3β-ol (3), and six polyketides: regiolone (4), 4,6,8-trihydroxy-3,4-dihydronaphthalene-1(2H)-one (5), 2,5-dimethyl-7-hydroxychromone(6), 2-methyl-5-carboxymenthyl-7-hydroxychromone (7), (+)-citreoisocoumarin (8), and de-O-methyldiaporthin (9). Compounds 1−9 exhibited no antioxidant activity and 4−9 did not display phytotoxic effects on ginseng roots.   Conclusion  Compounds 1−9 are isolated for the first time from R. panacis, enriching the database of secondary metabolites of this strain. Among them, compounds 4−9 exhibit various biological activities, but do not cause lesions in the isolated ginseng roots in the evaluation of phytotoxic activity. [Ch. 4 fig. 1 tab. 29 ref.]
Dynamic study on tree layer of deciduous broad-leaved forest in Mount Tianmu from 1996 to 2017 under climate change
ZHENG Xiao, WANG Tong, PANG Chunmei, SONG Sijing, DING Shan, YU Shuquan
, Available online  doi: 10.11833/j.issn.2095-0756.20230185
  Objective   This study aims to investigate the effect of climate change from 1996 to 2017 on the community composition and structure, biodiversity, and flora of trees with DBH≥10 cm in the deciduous broad-leaved forest layer of Mount Tianmu.   Method   A sample plot survey was conducted on 25 sample plots of 400 m2 of deciduous broad-leaved forest in the National Nature Reserve of Mount Tianmu, Zhejiang Province, China. Phase 2 (1996 and 2017) survey data and meteorological data of Mount Tianmu from 1996 to 2017 were used to analyze the dynamics of the tree layer in a deciduous broad-leaved forest.   Result   (1) The composition of life form of tree species in the tree layer changed significantly. The proportion of evergreen tree species increased from 17.5% to 35.5%, an increase of 102.9%, and the proportion of deciduous tree species decreased from 82.5% to 64.5%, which decreased by 21.8%. (2) The tree species in the tree layer changed drastically, with an exit of 8 species in 6 genera of 4 families, and entry of 4 species in 3 genera of 1 family. The exit and entry tree species reached 27.3%. The exit and entry of rare and occasional species were the keys to the change in species number in the tree layer. (3) The role of evergreen tree species in the tree layer was increasing. The variation range of the top 17 dominant tree species in the important value was 47.1%. Among them, the important value of Daphniphyllum macropodum, an evergreen tree species, increased from 1.88% in the 19th place to 10.36% in the 3rd place. The proportion of important values of evergreen tree species increased from 22.6% to 36.3%. (4) The α diversity of the tree layer decreased slightly, and the decline in various indices ranged from −9.1% to −3.1%. The α diversity index of evergreen tree species increased, ranging from −3.0% to 51.8%. (5) The flora tended to be tropical. The proportion of tropical components in the family increased from 55.6% to 58.3%. The proportion of tropical elements in the genus increased from 25.0% to 30.3%. (6) The diameter class structure showed an inverted J type, and the community was stable. The number of small-diameter evergreen tree species increased by 165.3%, while the number of medium-diameter evergreen tree species increased by 45.5%. There was no significant change in the large-diameter species. In 1996, there were 11 growth-type tree species, 1 stable-type tree species, and 4 declining-type tree species. In 2017, there were 7 growth-type tree species, and 5 stable-type tree species, and declining-type tree species did not change. Tilia chingiana, Cyclocarya paliurus, Cladrastis wilsonii, and Acer pictum changed from growth-type to stable-type. The growth potential of Pinus taiwanensis, Cyclobalanopsis shennongii, Cornus kousa ssp. chinensis, Daphniphyllum macropodum and Acer sinopurpurascens increased.   Conclusion   Under climate warming and humidification, the dynamic change of the tree layer in the deciduous broad-leaved forest in Mount Tianmu is very significant. The appearance of the tree layer in the deciduous broad-leaved forest has transitioned from the dominance of deciduous tree species to the balanced state between evergreen and deciduous trees, with a slight decrease in biodiversity and a trend towards tropical elements in the flora. [Ch, 7 tab. 39 ref.]
Effects of metal ions on digestion and metabolism of Odontotermes formosanus
QI Mengwen, SHEN Yi, YANG Guiying, YU Ting, LI Wuhan, ZHOU Qihuan, XIE Xiaojun, ZHU Yaning, MO Jianchu
, Available online  doi: 10.11833/j.issn.2095-0756.20230219
  Objective  This study aims to explore the role of metal ions in influencing the digestive generation process of Odontotermes formosanus, which is beneficial to explore the potential value of resource treatment of agricultural and forestry waste and kitchen waste containing metal ions by O. formosanus.   Method  According to the concentration gradient method, the bait containing different mass fraction of Al3+, Ca2+, Fe3+ and Mg2+ was fed to O. formosanus to determine the maximum edible mass fraction of metal ions in bait for O. formosanus. ICP-OES was used to measure the corresponding metal elements in O. formosanus body and new-built fungus combs, and to obtain the effects of feeding baits containing Al3+, Ca2+, Fe3+ and Mg2+ on the corresponding metal elements mass fraction in O. formosanus body and new-built fungus combs. The activities of laccase and cellulase in O. formosanus body and new-built fungus combs were determined by kit method, and the effects of feeding baits containing Al3+, Ca2+, Fe3+ and Mg2+ on the activities of these enzymes were determined.   Result  The maximum edible mass fraction of Al3+, Ca2+ and Fe3+ in baits of O. formosanus was 1.00 g·kg−1, and Mg2+ in baits was 10.00 g·kg−1. Mg enrichment occurred both in O. formosanus body and new-built fungus combs after feeding baits containing 10.00 g·kg−1 Mg2+; Fe was only enriched in new-built fungus combs after feeding baits containing 1.00 g·kg−1 Fe3+. The laccase activity in O. formosanus body improved significantly after feeding baits containing 1.00 g·kg−1 Al3+. The laccase activity in O. formosanus body improved significantly, but the cellulase activity reduced significantly after feeding baits containing 1.00 g·kg−1 Ca2+. The laccase activity in O. formosanus body and cellulase activity in new-built fungus combs improved significantly, but the laccase activity in new-built fungus combs and cellulase activity in O. formosanus body reduced significantly after feeding baits containing 1.00 g·kg−1 Fe3+. The cellulase activity in O. formosanus body and the laccase activity in new-built fungus combs improved significantly, but the cellulase activity in new-built fungus combs reduced significantly after feeding foods containing 10.00 g·kg−1 Mg2+.   Conclusion  O. formosanus can feed on baits containing 1.00 g·kg−1 Al3+, Ca2+ or Fe3+ or 10.00 g·kg−1 Mg2+, and 1.00 g·kg−1 Al3+ can improve the combined degradation of lignin by O. formosanus and fungus-comb microbiome. O. formosanus have application potential for resource treatment of agricultural and forestry waste and kitchen waste. [Ch. 3 fig. 1tab. 28 ref.]
Mechanisms of plant P acquisition coordinated by arbuscular mycorrhizal fungi and phosphate-solubilizing bacteria
GAO Ning, XING Yijing, XIONG Rui, SHI Wenhui
, Available online  doi: 10.11833/j.issn.2095-0756.20220765
Phosphorus is an important element for biological growth and development. Phosphate-solubilizing bacteria and arbuscular mycorrhizal fungi are directly involved in the process of soil phosphorus activation and plant phosphorus acquisition, which is of great significance for the turnover of phosphorus nutrients in ecosystems and the formation of plant yield. In this paper, the mechanism of plant-microorganism collaboration in promoting the efficient absorption and utilization of phosphorus nutrients was summarized and analyzed from four aspects: the strategy of plant phosphorus acquisition and utilization, the coordination pathway of arbuscular mycorrhizal fungi for plant phosphorus absorption, the coordination pathway of phosphate-solubilizing bacteria for plant phosphorus absorption, and the synergy of plant-arbuscular mycorrhizal fungi-phosphate-solubilizing bacteria. It was found in the analysis that the phosphorus acquisition process of plants required efficient root adaptability, which promoted soil phosphorus activation by regulating root morphological traits and changing the composition and secretion of root exudates. Arbuscular mycorrhizal fungi could promote the changes of soil biological activity and chemical properties in rhizosphere and hyphosphere by exchanging mutually beneficial symbiotic substances with plants, and promote plants to obtain phosphorus. Phosphate-solubilizing bacteria had a positive interaction with plants and arbuscular mycorrhizal fungi at the soil interface, secreting a variety of organic acids, reducing soil pH, and increasing the activities of phosphorus activation-related enzymes to improve soil available phosphorus levels. On this basis, research prospect of plant-arbuscular mycorrhizal fungi-phosphate-solubilizing bacteria interaction to promote plant phosphorus uptake was prospected. Future research should focus on the following aspects: the role of mycorrhizal traits in the interaction system, analysis and identification of metabolite composition and potential functions of the member of the interaction system, and to explore the effects of biotic or abiotic factors on the construction and functional assembly of soil microbial community. [Ch, 141 ref.]
Preparation and antibacterial properties of gallic acid modified bamboo powder
YE Jinzhi, XU Juan, YANG Jing, YANG Haiyan, WANG Dawei, SHI Zhengjun
, Available online  doi: 10.11833/j.issn.2095-0756.20220718
  Objective  This study, with gallic acid modified Dendrocalamus giganteus (DG) prepared by esterification reaction, is aimed to investigate the effect of gallic acid (GA) on antibacterial performance of DG.   Method  The modified products (DG-GA) were characterized by Fourier transform infrared spectrometer, X-ray diffractometer, scanning electron microscope and thermogravimetric analysis before the antibacterial tests were performed by shaking method after modification.   Result  Gallic acid formed graft copolymer with bamboo powder successfully with a layer of coating formed on the surface of bamboo fiber bundle, making the surface become smoother. After gallic acid modification, the thermal stability of bamboo powder increased by about 40 ℃, the inhibition rate against Escherichia coli increased from 30.70% to 93.24%, and the inhibition rate against Staphylococcus aureus increased from 32.18% to 75.29%.   Conclusion  The modification of gallic acid can obviously improve the inhibition ability of bamboo powder against gram-negative and gram-positive bacteria, making it an effective method to improve the antibacterial property of bamboo. [Ch, 8 fig. 26 ref.]
Effect of biochar-based fertilizer on root development, yield and quality of flue-cured tobacco in Chongqing tobacco growing area
SONG Peng, LI Hui, JIANG Houlong, ZHAO Pengyu, LI Lixiang, ZHAO Biao, ZHANG Jun
, Available online  doi: 10.11833/j.issn.2095-0756.20230161
  Objective   The objective is to explore the effect of biochar-based fertilizer on root development, and yield and quality of flue-cured tobacco (Nicotiana tabacum) in Chongqing tobacco growing area, in order to provide theoretical basis and technical support for the rational application of biochar-based fertilizer in this area.   Method   N. tabacum ‘Yunyan 116’ was taken as the research object, and three treatments including conventional fertilization (T1), biochar-based organic fertilizer (T2) and biochar-based compound fertilizer (T3) were set up to analyze the effect of biochar-based fertilizer on the physiological activity of flue-cured tobacco root, chemical quality and economic traits of flue-cured tobacco.   Result   The application of biochar-based fertilizer could optimize the physiological and nutrient indexes of tobacco root. The root activity in T2 was the highest after transplantation, which increased by 4.2%−46.8% compared with T1. The number of lateral roots and adventitious roots in T3 was the most, which increased by 11.6%−41.1% and 19.0%−53.1% respectively compared with T1. The contents of nitrogen and potassium in root system decreased with the growth of tobacco plant, and the decrease was the slowest in T2. The nicotine contents in root system increased first and then decreased, and those in T2 and T3 were higher. The application of biochar-based fertilizer could increase the yield and output value of flue-cured tobacco and improve the chemical quality of flue-cured tobacco. Among them, T2 treatment had the highest yield and output value, which increased by 16.9% and 22.6% respectively compared with T1. In addition, biochar-based fertilizer could improve the nitrogen alkali ratio, sugar alkali ratio and potassium chloride ratio of flue-cured tobacco, improve the coordination of internal chemical components and improve the quality of flue-cured tobacco. Correlation analysis showed that the potassium contents (at 30, 60 and 120 d after transplanting) and the nitrogen contents (at 60, 90 and 120 d after transplanting) in root system were most closely related to the chemical quality of flue-cured tobacco.   Conclusion   Biochar-based fertilizer is beneficial to the growth and development of flue-cured tobacco roots, and can increase the output value as well as the chemical quality of flue-cured tobacco. [Ch, 4 fig. 4 tab. 31 ref.]
Flowering characteristics and breeding system of Phalaenopsis japonica
CHEN Zhiguang, XU Yan, GE Hong, YANG Shuhua, ZHAO Xin, KOU Yaping, ZHU Jinyu, JIA Ruidong, WU Ronghua
, Available online  doi: 10.11833/j.issn.2095-0756.20230146
[Abstract](109) [HTML] (21) [PDF](16)
  Objective  This study, with an investigation of the breeding system of the Phalaenopsis japonica, is aimed to provide theoretical basis for P. japonica hybrid breeding and research basis for the preservation and protection of the plant germplasm resources of the endangered Phalaenopsis.   Method  With P. japonica in greenhouses taken as materials, their floral characteristics and flowering process were recorded for observation before the pollen viability and stigma acceptability were determined, the pollen histochemistry was analyzed, the hybridization index (OCI) was estimated and artificial pollination was tested.   Result  (1) The P. japonica blossomed from mid April to end of May, and was fragrant and the florescence of single plant lasted for 30 to 40 days and that of a single flower is about 30 days, with the bud stage being 1 to 7 days before flowering, the initial flowering stage being 1 to 5 days after flowering, the full flowering stage being 6 to 25 days after flowering, the final flowering stage being 26 to 30 days after flowering and the flower fading stage being 30 to 40 days. (2) The P. japonica was raceme with each plant having 1 to 2 inflorescences and each inflorescence having about 10 flowers. (3) The P. japonica pollen was nearly circular tetrad pollen which was mainly composed of lipids, suitable for insect pollination. (4) The P. japonica was monoecious and the pollen viability and stigma acceptability reached the highest in the blooming stage (flowering for 6 to 25 days) with the highest pollen viability being 84.98% and the hybridization index (OCI) of P. japonica being 4. (5) The fruit setting rate of natural pollination, natural self-pollination, and emasculation without pollination were 0 but the fruit setting rate of artificial self-pollination, artificial cross-pollination of the same plant, and artificial cross-pollination of different plant reached 60.00%, 80.00%, and 93.33% respectively. (6) The fruits of artificial cross-pollination between different plants had the highest quality, with the largest seeds, highest viability (82.69%), and largest amount of seeds (about 43000 seeds).   Conclusion  The flowering of P. japonica starts in mid April and ends at the end of May with the full blooming period lasting for about 20 days and its breeding system is a mixed mating system of self-pollination and cross-pollination that required pollinators. [Ch, 4 fig. 3 tab. 26 ref.]