2018 Vol. 35, No. 3
To determine the effect of addition of acidulated pig biochar on phosphorus (P) availability and fractionation in soils, an incubation experiment was carried out using a randomized complete block design having five treatments:an untreated control(ck), acidulated pig biochar, raw pig biochar, single superphosphate, and calcium magnesium phosphate, with three replications. Each amendment was mixed with soil at 0.1% (w/w) and placed in a plastic pot. Soil samples were taken from each pot after a 210-day incubation period to assess P fractionation using modified Hedley's sequential extraction procedures. A correlation analysis was also included. Results showed that, compared to ck, electrical conductivity (EC) of the soil increased (P < 0.05) with raw pig biochar (24%) and acidulated pig biochar treatments (14%), but there was no significant effect on soil pH. Compared to ck, with the same application rate acidulated biochar was more effective (P < 0.05) than pig biochar for improving the proportions of soil labile and moderately labile phosphorus; whereas, no significant differences in these P proportions between the acidulated biochar and the fertilizer treatments were found. Compared to ck, the percentage of labile P pools significantly (P < 0.05) increased in all treatments, but there were no significant differences between biochar and fertilizer treatments. In comparison with ck, moderately labile P pools increased (P < 0.05) in biochar (36.2%) and fertilizer treatments (77.2%) in the following order:acidulated pig biochar > superphosphate > calcium magnesium phosphate > raw pig biochar. The percentage of stable P pools decreased (P < 0.05) with addition of the amendments, and the proportion of the stable P pools was negatively correlated to the proportion of labile (R2=0.86, P < 0.01) and moderately labile (R2=0.94, P < 0.01) P pools. The acidulated pig biochar treatment significantly (P < 0.05) increased the concentration of all P fractions and maintained a relatively low proportion of stable P in the treated soil. In conclusion, with significant differences in soil P concentrations and fractionations between acidulated pig biochar and chemical P fertilizers treatments tested, it would be potentially viable to use acidulated pig biochar as an alternative P fertilizer and substitute for superphosphate and calcium magnesium phosphate in agricultural production.
This study used hydrothermal carbonization technology to convert pig manure into hydrochar. The effect of carbonization temperature (160, 180, 200, 220, and 240℃), carbonization time (1, 5, and 8 h), and moisture content of pig manure (70%, 75%, and 80%) on major nutrients, and the recovery rate of hydrochar were determined. Results showed that the nutrient content in hydrochar was rich; the organic carbon (OC) ranged from 232.0-328.0 g·kg-1, total nitrogen (TN) ranged from 25.2-31.8 g·kg-1, phosphorus (P) ranged from 21.5-30.6 g·kg-1, and potassium (K)ranged from 3.4-12.5 g·kg-1. When the carbonization temperature from 160℃ to 240℃, the content and recovery rates of N and OC in hydrochar from 66.29% to 41.95% and 49.61% to 29.07%, respectively; with the decrease in K being 7.5 g·kg-1; whereas, the content of P increased 7.7 g·kg-1 with the recovery rate remaining almost unchanged. Because carbonization time and moisture content of the raw material were similar to that of carbonization temperature and because they had little effect; carbonization temperature was the main factor affecting the content of nutrient components in pig manure.
To provide a theoretical basis for evaluation of the carbon sequestration status of a soil ecosystem in a Castanopsis fargesii forest and for development of a sustainable forestry management strategy in the study region, soil from C. fargesii in Dagangshan, Jiangxi Province was taken as the research object. Using the method of potassium dichromate volumetric and mineralization with a constant indoor temperature of 28℃ and then fitted with a double exponential equation to get the contents of soil organic carbon, soil active carbon and slow-release carbon respectively. Characteristics of spatial and temporal variation for soil organic carbon (SOC), active carbon, and slow-release carbon content were analyzed using one-way ANOVA and multiple comparisons between data using the LSD method. Results showed that the soil organic carbon, slow-release carbon and active carbon contents had the same profile characteristics and accumulated in 0-20 cm surface soil. Compared to April, June, October and December, the interlayer content in August changed significantly (P < 0.05). For a depth of 0-100 cm, the total SOC, active carbon and slow-release carbon content had the same temporal variation characteristics increasing from April to June, reaching a maximum in August, and then decreasing. Conversion of soil slow-release carbon and active carbon from April to June and August to October was strong; soil slow-release carbon content was changed significantly (P < 0.05) and further lead SOC changed significantly in this stage. There was no significant difference in soil active carbon content between the different time. From April to June, the soil active carbon content for 0-20 cm was the fastest growing stage with a rate of increase of 1.30 g·kg-1·month-1, but there was no significant increase in soil active carbon content because of the conversion of active carbon into slow-release carbon and the plum rain season. In general, temporal and spatial changes of total SOC and slow carbon content were more consistent.
To contribute to a further understanding of soil respiration dynamics and to help to provide an accurate calculation of carbon emissions, the relationship between soil respiration dynamics and influencing factors for six plantation types:Eucalyptus urophylla, E. pellita, E. torelliana, E. camaldulensis, E. urophylla×E. grandis and Pinus elliottii×P. caribaea, along the Leizhou Peninsula was field continuously using the LI-8100A (LI-COR, USA) for spatial and temporal variability in the soil respiration rate from March 2016 to February 2017. With this data, analyses (including correlation analyses) of spatial and temporal variation and analyses of the relative importance of key factors influencing these parameters were undertaken. Results showed that soil respiration rates for the six plantations studied, in relation to soil temperature, all had a single peak in their pattern with both index and quadratic models able to simulate relationships between soil respiration and soil temperature or moisture (0-10 cm). Temporal variation of the soil respiration rate was driven by both soil temperature and moisture with a two-factor equation (soil temperature and moisture at 10 cm) explaining 44.8% to 83.9% of the variation in soil respiration. Spatial variation of the soil respiration rate was mainly affected by soil bulk density, leaf area index, total soil porosity, and non-capillary soil porosity, with correlations between these parameters and soil respiration rates highly significant (P < 0.01). Soil surface carbon flux was also correlated to soil organic carbon density (P < 0.05) except for soil bulk density, total soil porosity and non-capillary soil porosity. The annual average of soil respiration and soil surface carbon flux in both E. urophylla and E. torelliana plantations were all significantly higher than E. pellita, E. camaldulensis, E. urophylla×E. grandis plantations and P. elliottii×P. caribaea plantation (P < 0.05), and with no significant differences between E. urophylla and E. torelliana plantations. In total, the spatial and temporal heterogeneity of soil respiration was influenced by various factors, which is the most important consideration in estimating soil respiration flux.
Soil micro-biota influence plant survivorship and growth through plant-soil feedback, an important theory focus for controlling and selecting introduced species, with much research on plant-soil feedback showing that species or methods can influence experimental results. To compare the response of two tree species to different plant-soil feedback, differing plant-soil feedback effects of which we chose the inoculum by two kinds of soil particle sizes (< 0.12 mm, < 2.00 mm) or by two soil sources (conspecific, heterospecific soil) to sterilized peat soil with 10 replicates each treatment were established and observed in seedlings of two alien tree species, Fraxinus americana and Acer negundo, in China. Pearson correlation analysis and Student's t test were used for analysis. Results showed that with a small size class of soil biota, F. americana biomass increased (P < 0.05); whereas, A. negundo biomass decreased (P < 0.05). No significant differences in arbuscular mycorrhizal (AM) fungi colonization ratios in two size class of soil biota between these two species were noted (P < 0.05). With conspecific soil the biomass of F. americana was significantly lower (54.4%) and with A. negundo it was significantly higher (102.2%) than that of heterospecific soil (P < 0.05). F. americana also showed a significant difference in fungi colonization rates (P < 0.05); whereas, A. negundo did not. The correlation analysis and significance testing suggested that the correlation coefficients on biomass and composition of AM structures, especially the ratio of vesicles, were distinctively influenced by soil micro-biota (r=0.798, P < 0.01). In their native habitats, both F. americana and A. negundo may benefit from plant-soil feedback, as negative feedback helps the former to avoid generational competition and positive feedback helps in regenerating of the latter species; meanwhile in China, attention should be paid to the risk of invasion for A. negundo because of its positive feedback effect with soil. This research could also be a good reference for relevant research about plant-soil feedback and subsequent introduction of F. americana and A. negundo.
Taking moso bamboo (Phyllostachys edulis) seedlings and heavy metal contaminated soil for research object, the changes of chlorophy fluorescence parameter, concentration of heavy metals in plant and concentration of heavy metal and EDTA in soil solution were studied through soil column leaching test, which was expected to provide scientific basis for the strength of chelate-induced phytoremediation of contaminated soils. The results revealed that chlorophy fluorescence parameter was inhibited while treated with EDTA and organic acids, and the inhibitory effects reached peak at the treatment of 30.0 mmol·kg-1 organic acids. The addition of EDTA promoted the uptake of Zn, Cu and Cd by moso bamboo, while it was useless for organic acids. The activation effect reached peak under the treatment of 3.0 mmol·kg-1 EDTA. The concentration of heavy metal in the soil layer of 20 and 40 cm increased along with time, and achieved stability after 4 times collection, and reached peak at the last collection. For the soils treated with organic acids, they reached peak at the second collection, and then decreased gradually. The content of EDTA in soil solution was mainly concentrated in the 5 cm soil layer, and decreased along with time, and then kept stability at the fifth and ninth day, which was at the range of 110.9-122.9 mg·L-1 and 257.8-263.3 mg·L-1 respectively. It could be concluded that potential phytoremediation capability of moso bamboo in heavy metals contaminated soils would be enhanced effectively with application of EDTA, however, the environmental risks should be considered synthetically when using.
Three-dimensional microclimate models within a heterogeneous mixed scene consider more structural factors than a one-dimensional, however, a 3D model has relatively few reports because of its complexity theory. To evaluate the capacity and potential of 3D models in terms of flux energy simulation, this research used the ENVI-met model, as an example, with data from the Chinese Heihe program and the Canadian BOREAS program. Daily and seasonal variation between observed and simulated results, as well as model sensitivity in forests with different spatial distribution patterns, was analyzed. Results (1) for fitted R2 values of the model showed that in spring R2=0.75, in summer R2=0.76, and in autumn R2=0.55. Modeling day change tendency was consistent with observed data where differences between observed and simulated daily sensible and latent heat fluxes were below 10%. Accuracy for sensible heat flux, latent heat flux and solar shortwave radiation simulation were 68%, 63% and 80%, respectively. (2) The model's energy balance ratio (EBR) was 92.9%, meaning it was relatively stable and insensitive to meteorological parameters. (3) The sensible heat flux value of a lumped forest distribution was 155.52 W·m-2 higher than an uniform distribution with daily changes in a wide range. Overall, ENVI-met had favorable accuracy in terms of surface energy flux simulation, and reflected flux energy distribution differences caused by forest spatial distribution patterns; so the 3D model could provide an effective means to regional climatology research.
To screen the fast-growing Chinese fir family for steady traits and strong adaptability for extension, growth differences of 21 Chinese fir (Cunninghamia lanceolata) families were compared for different site conditions and the interactions between growth traits and sites were discussed. Two sites treatments in Changle Forest Farm and Kaihua Forest Farm, and a control in the second generation seed orchard, with randomized block design and eight replications, were set in Zhejiang Province. Tree height and diameter at breast height (DBH) of 3-year-old Chinese fir families were investigated for each tree. A one-way analysis of variance followed by Duncan's multiple comparison test was used to determine statistical significance of growth triats across two sites. Results showed significant differences(P < 0.01) on tree height and DBH with Chinese fir in the same family for different sites and for different blocks of the same site. Chinese fir planted in cutover land of Pinus massoniana at Changle Farm had higher tree height (37.77%) and greater DBH (86.58%) than that on cutover land of Chinese fir at Kaihua Farm. Tree height also showed significant differences(P < 0.01) among families. According to the analysis on growth rate, stability, and adaptability of tree height and DBH, seven families of Chinese fir grown at two sites which showed favorable traits at the young plantation stage were selected. These seven families could be widely planted in these two sites as well as in other sites having similar conditions.
To explore the effect of density on growth of young Mytilaria laosensis stands with natural seed regeneration on clearcut land, a single factor randomized block design experiment with natural spacing (ck treatment, three replications) and spaced seedling(TA, TB and TC treatments, three replications) stands was established, and variance analysis of the stands were analysed with Least Significant Difference methods in Data Processing System(14.5), to test diameter at breast height (DBH), tree height, and single volume. Results showed that:(1) between ck and spaced seedling stands, during 3.5 years after spacing, stand density significantly decreased (P < 0.01) the average growth of total growth and annual increment of DBH, tree height, and single volume in the ck stands types; whereas, the total growth of DBH, tree height, and single volume of dominant trees with both stands were not significantly affected (P > 0.05). Spaced treatments(finished in 1.5 years old of seedling, remain density in hectare:TA 1 650, TB 2 800, and TC 2 500)significantly improved (P < 0.01) the average growth of the stands and reduced differentiation of diameter grades in the stands. (2) The higher stand density(ck), the earlier intersection time of the average growth curve and the annual growth curve for average DBH or tree height of the stand was appeared. Also, the peak value of annual growth for average DBH of ck stands occurred in the second year, and the peak value of spaced stands was during the second and 4th year. Before the 5th year, it was fast growth period for the stands with natural seed regeneration, so spacing was very important with radial growth of the stands. (3) The time of intersection for curves of average growth and annual growth of tree height in the ck stands was between the second and third year, but with the spaced stands did not intersect before the 5th year. Growth for tree height of dominant trees in all stands before the 5th year was fast(the annul increment of top height in each treatment was more than 1.49 m in each year). (4) Different types of stands had different diameter distributions; the ck stand had an inverted J distribution, but the spaced stands had an approximately normal distribution. (5) In the spaced stands, after 3.5 years, the average growth for DBH, tree height, and volume of less dense forest stands(TA treatment stands) was better than those with higher density treatments(TC or TB stands). Thus, understanding of the mature period for seeds, the seed falling-stage, and natural regeneration characteristics of Mytilaria laosensis could enhance the scientific cutting time, cutting methods, clean ways for removing residues, shrubs, and herbaceous plants, and methods for spacing seedlings to enable effective natural regeneration on cutover land thereby promoting forest growth.
Tetrastigma hemsleyanum has obvious pharmacological effects on inhibitting tumor cell proliferation and migration clinically. It is on the verge of extinction with the increasing demand over the past decade, so bionic planting is imperative to meet the medical needs. In this paper, we explored suitable light intensity conditions for the T. hemsleyanum growth by consideration that T. hemsleyanum grows in the forest wildly and is sensitive to strong light. Two-year-old T. hemsleyanum cuttings were shaded with different gradients treatment as test materials. The shading gradients were set as full light(ck), shade 30%, 50%, 70% and 90%. The responses of photosynthetic characteristics to light intensity were analyzed in different growth stages (rapid growth period and slow growth period). Following indicators were also measured:contents of photosynthetic pigments were determined by 95% alcohol extraction; light photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) and transpiration rate (Tr) were measured by LI-6400XT portable photosynthesis system; light response curve (LSP), light compensation point (LSP), quantum efficiency (AQE), dark respiration rate (Rd) and maximum net photosynthetic rate (Pmax) were calculated, and the light response curve was fitted. Results showed that trends of chlorophyll a (Chla), chlorophyll b (Chlb), total chlorophyll (Chl) and carotenoid (Car) were increased with the increase of shade gradients, but the contents of photosynthetic pigment changed little in different periods; most photosynthetic indices also showed increasing trends with the increase of shading gradients, reached the maximum values in the treatment of 70% shade, then reduced, the values of rapid growth period (Pn was 4.19 μmol·m-2·s-1, Gs was 53.54 mol·m-2·s-1, Tr was 0.98 mmol·m-2·s-1, LSP was 340.49 μmol·m-2·s-1, AQE was 0.18 mol·mol-1, Rd was 1.20 μmol·m-2·s-1 and Pmax was 5.34 μmol·m-2·s-1) were 41.67%~67.26% higher than those of slow growth period (Pn was 1.74 μmol·m-2·s-1, Gs was 17.53 mol·m-2·s-1, Tr was 0.36 mmol·m-2·s-1, LSP was 159.28 μmol·m-2·s-1, AQE was 0.06 mol·mol-1, Rd was 0.70 μmol·m-2·s-1 and Pmax was 2.45 μmol·m-2·s-1); Ci and LSP showed trends of decreasing first and then tending to be stable. It showed that the photosynthetic activity decreased and plant growth slowed down with unsuitable environmental conditions such as strong light, high temperature and low humidity. The analysis of results indicated that the growth of 70% shading was appropriate in different growth periods. This paper discussed the relationship between physiological characteristics and light intensity of T. hemsleyanum in different growth periods, enriches the research results of physiological aspects, and provided basic theory for artificial cultivations and under-forest-cultivation.
To reduce the incidence of chilling injury for cucumber during storage and transportation, the effects of ultraviolet (UV)-C and heat treatment alone or in combination on chilling injury, membrane permeability, malondialdehyde, ascorbic acid, total phenol, total antioxidant capacity, and antioxidant enzyme activities of a cucumber variety called 'Deltastar' stored at 4℃ were studied. Results showed that compared with the control, UV-C and heat treatment alone, 5.0 kJ·m-2 UV-C combined with heat at 37℃ could induce higher antioxidant enzyme activities, such as superoxide dismutase (SOD), catalase activities (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) in cucumber. Higher total phenolics, ascorbic acid content, and total antioxidant capacity were also realized; thereby, delaying membrane oxidation caused by the accumulation of reactive oxygen species with low temperature stress. So, the combined treatments prevented an increase in the relative leakage rate and the accumulation of malondialdehyde; thus reducing the occurrence of chilling injury. At the same time, UV-C combined with the heat treatment also maintained a better hardness, more soluble solids, and greater chlorophyll content. Overall, UV-C and heat treatment inhibited the chilling injury of cucumber synergistically making this study beneficial for reduction of chilling injury and maintenance of cucumber during storage and transportation at low temperatures.
Oleoresin is a secondary metabolite with a high economic and ecological value, and it is mainly stored in the resin channel system of needles and trunk xylem and phloem of the genus Pinus. Study on the relationship between oleoresin yield and their anatomical characteristics is conducive to selective breeding of superior tree with high-yielding oleoresin of Pinus yunnanensis and establishment of directional cultivation technology system of high-yielding forest. The relationship between oleoresin and the anatomical characteristics of needles and trunks was studied, and the differences in the anatomical characteristics of the needles and trunks of high-and low-yielding trees were compared and analyzed. The results showed that, the number of resin canals and secrete cells in the needles and trunks of high-yielding oleoresin pines were significantly higher than those of low-yielding oleoresin pines. With the increase of the number of resin canals in the needles and trunks, the oleoresin yield was also increased(P < 0.01). In addition, the loading of the number of resin canal in xylem was the largest in the principal component analysis. The result implied that the number of resin canal in xylem could be proposed as an important indicator for breeding high-yielding oleoresin P. yunnanensis.
The relationship between rice seed storage tolerance and dormancy characteristics was determined for two Oryza sativa subsp.sativa (rice) cultivars with different characteristics of dormancy[4K58 (Ⅱ-32B dormant), 4K59 (Ⅱ-32B)] and their F2 seeds (C178, C179) hybridized with a sterile line (Ⅱ-32A) as materials.Different aged seeds (0 d, 3 d, 6 d, or 9 d) of these four varieties were acquired by the artificial accelerated aging method.Seed conductivity, single nucleotide extract content, germination indices, and growth parameters of seedlings were measured in a CRD design with treatments of ck, 3, 6, 9 d with 3 replications.All data obtained were statistically analyzed with one-way ANOVA and least significant difference method (LSD) test.Results showed that seed conductivity, and single nucleotide extract content of aged 4K58 seeds were significantly higher than those of 4K59 (P < 0.05) with maximum discrepancy of single nucleotide extract content in multiples of 14.5.However, germination energy and germination index of 4K58 were significantly lower than those of 4K59 (P < 0.05) having a mean germination time that was significantly higher than 4K59 (P < 0.05).Also the single nucleotide extract content and mean germination time of aged C178 seeds were significantly higher than those of C179 (P < 0.05); whereas, germination percentage, germination index, shoot length, and fresh weight were significantly lower than C179 (P < 0.05).Thus, storage properties may be passed on to succeeding generations, and rice seed with dormant properties may not be suitable for storage.
To determine causes of seed dormancy with Paeonia rockii seeds, this research studied seed coat permeability, inhibiting substance strengths using peas as the material, the growth status of different explant cultures and did difference analysis. Results showed that permeability of seed coat had certain effects on water absorption and respiration intensity of seed; some of the peas placed in endosperm, embryo, and seed coat extracts with P. rockii seeds before germination, took root with rooting rates of endosperm < embryo < seed coat; however, none of the epicotyls germinated. Rooting rates of peas in endosperm and seed coat extracts with germinated or sprouted P. rockii seeds were higher than those with seeds that had not germinated; they all had partial epicotyls sprouting, but no differences were found between those with germinated and sprouted P. rockii seeds. Rooting rates of P. rockii increased with complete seeds < peeled seeds with seed coats alongside < peeled seeds < embryos (embryos or embryos without cotyledons); however, none sprouted. Both embryos and embryos without cotyledons required low temperature treatment before they could germinate. Thus, (1) seed coat permeability, inhibitory substances in the seed coat and endosperm were reasons for hypocotyl dormancy with P. rockii seeds; (2) changes of inhibitory substances from rooted seeds to sprouted seeds had nothing to do with epicotyl dormancy meaning reasons for epicotyl dormancy were probably inside the embryo; and (3) low temperature could release epicotyl dormancy, but removing seed coat, endosperm, or cotyledons could not.
To determine the effect of culture medium, temperature, and time on pollen germination rates, different materials:Magnolia biondii, Magnolia 'Changhua', Magnolia 'Danxin' and Magnolia cylindrica were used to study variation in pollen viability. Treatments of sucrose, H3BO3 and PEG-4000 were used to determine the effects on pollen germination with orthogonal experiments alone as well as for interactions. Results showed that (1) Different individuals need certain concentrations of the culture medium:Magnolia biondii was 50 g·L-1 sucrose + 50 mg·L-1 H3BO3 + 200 g·L-1 PEG-4000; Magnolia 'Changhua' was 100 g·L-1 sucrose + 200 mg·L-1 H3BO3 + 200 g·L-1 PEG-4000; Magnolia 'Danxin' was 100 g·L-1 sucrose + 100 mg·L-1 H3BO3 + 150 g·L-1 PEG-4000 and Magnolia cylindrica was 50 g·L-1 sucrose + 100 mg·L-1 H3BO3 + 250 g·L-1 PEG-4000. (2) For pollen viability, 25℃ was the best temperature, higher temperatures inhibited pollen viability. (3) At 9 h, Magnolia biondii (71.19%) and Magnolia cylindrica (59.82%) had the highest germination rates (P < 0.05); whereas, at 12 h Magnolia 'Changhua' (44.50%) and Magnolia 'Danxin' (23.43%) had the highest germination rates(P < 0.05).
Shengjin Lake Wetland is an important habitat for winter cranes of China, and changes of land-use structures in the area have had a vital influence on winter cranes and their habitat. According to the study on the changes of the population and habitat of the cranes in the Shengjin Lake Wetland, a constructive suggestion for the cranes and habitat protection would be presented. TM remote sensing images for years 1986-2015 were selected, and a land-use change model was used to calculate the comprehensive index of land-use of the years from 1986 to 2015, and the change value of land-use degree in different periods was obtained. The land-use transformation method was employed to calculate the transfer probability of land-use of Shengjin Lake Wetland during the period from 1986 to 2015, and the transfer of the winter crane habitat was analyzed. Results showed that the degree of land-use change fluctuated greatly in different periods with a comprehensive index of land-use degree between 220 and 260. Also land-use was based on woodlands, marshlands, and waters and their effect on the habitat was limited; marshland had the highest retention rate among the crane habitats being 34.44%. Reed beach land had the lowest rate at only 15.36% and was mainly transferred to marsh (23.22%) and dry land (18.16%). Mud was mainly transferred to water (31.79%) and farmland (27.75%). Thus, except for the period from 2011 to 2015, the change in habitat area was basically consistent with the change in the number of cranes.
For value-added utilization with fast-growing wood of Pinus radiata as well as promotion of added value of the products, outdoor scrimbers with varying densities were prepared with P. radiata as the raw material via the manufacturing technology of high-performance reconstituted wood. Then, effect of density on porosity, water resistance, and mechanical strength of the obtained scrimbers was determined. Results showed that the porosity of air-dry logs was 68.00%. Also, scrimber porosity decreased as density increased and the minimum was 2.11%. Both water resistance and mechanical strength were trengthened with an increase in density. When the density increased from 0.80 to 1.39 g·cm-3, thickness swelling rate (TSR) decreased 21.55% and water absorption rate (WAR) decreased 76.88%; whereas, modulus of rupture (MOR) increased 116.47% and horizontal shear strength (HSS⊥) increased 86.29%. It suggested that the density of P. radiata scrimbers had a big impact on porosity and physical-mechanical properties.
Wood sawing is a closed cutting process. The side edges are involved in wood sawing and the influence of the radial clearance angle becomes particularly important. To explore the influences of the side edges on the cutting force in the wood sawing and quantify it, this study with Pinus sylvestris (pinus) and Fraxinus mandshurica (ash) as samples, used the four factors three levels of BBD test Design in the modeling response surface methodology for a cutting force experiment that was carried out with a single sawtooth having different radial clearance angles. The multiple response surface regression model of a cutting force was established by considering the effects of radial clearance angles, cutting thickness, moisture content, and rake angle. Results using the response surface methodology showed that the multiple regression mathematical model of the cutting force had a high accuracy and reliability (R2=0.92 and R2=0.94). The radial clearance angle had a certain impact on the cutting force in wood closed cutting. Also with an increase in radial clearance angle, the cutting force decreased slowly. Overall for both kinds of wood, cutting thickness had an extremely important impact on cutting force, followed by the rake angle, then wood moisture content, and finally the radial clearance angle.
To determine the influence of meteorological data at different distances from a research site on the accuracy of a prediction model for water content of fine fuels, a model was established and tested in the spring and autumn of 2010. Continuous observations were conducted on the moisture content of fine fuels in Pinus sylvestris var. mongolica, Larix gmelinii, and Betula platyphylla stands in the Pangu Forest Farm of Tahe County, Da Xingan Ling Prefecture and compared to meteorological data such as precipitation (R), total precipitation for n d (Ran), average relative humidity (Han), daily maximum temperature (Tmax), and drought days (d). Results indicated that for meteorological factors in spring and autumn, R was positively correlated with Ran and Han (n=1-2), but negatively correlated with Tmax and d. The model using the meteorological data of the Pangu Meteorological Station was more accurate than the Tahe Model which was further away having a significantly lower mean absolute error (EMA) of 2.7% and mean relative error (EMR) of 22.6% (P < 0.01). From the heterogeneity of the fuels and the accuracy of the model, attention should be paid to the selection of time and the spatial scale of the meteorological factors when modeling meteorological data collection so as to ensure model accuracy.
Under-forest economy as an ecological and economic compound development model, plays an important role in increasing households' income and promoting economic development in forest areas. Based on the survey data from Lin'an, Kaihua, Qingyuan, and Longquan, which are counties(city or district) in Zhejiang Province, this research analyzed the subjective reasons why many households in the collective forest areas were unwilling to develop under-forest economy as well as the households' demand for policy of developing under-forest economy, then used the quantitative analysis method to identify the objective determinants of the households' willingness to develop under-forest economy. The findings indicated that the farmers who do not want to develop under-forest economy believe that the major reasons were shortage of labor and resource advantages, inconvenient traffic, lack of funds and low investment return. Financial subsidies were most popular policy for under-forest economy development, followed by technical extension and traffic infrastructure construction. The regression results showed that the major determinants of households' willingness to develop under-forest economy included the characteristics of household heads, forest land resources, the proportion of the old laborers and the proportion of forestry income in the household, and whether having forest insurance or not.
To solve problems of lacking adequate evidences and real-time monitoring in the process of monitoring sewage disposal, and improve the monitoring efficiency of the sewage disposal and emergency response capability of pig farms, we presented an exploratory smart monitoring strategy, model and Ecological analysis method on hog sewage disposal under the ecological treatment mode. Based on the treatment process of hog sewage and the analysis of the monitoring principle of hog sewage disposal under the ecological treatment mode, the research proposed to use multiple sensors to monitor and collect the real-time data and conduct qualitative and quantitative analysis of the data with the Ecological mathematical method. Using the Ecological method, this paper analyzed and built a smart monitoring model for hog sewage disposal under the ecological treatment mode, and proposed the data monitoring procedures and algorithm to make the real-time judgment of the inappropriate disposal of hog sewage. Application of the strategy to building an early-warning platform of hog sewage disposal can effectively conduct the real-time monitoring of hog sewage disposal, and improve the efficiency and accuracy of the sewage disposal monitoring.
Plant grafting healing is a process in which the same or heterogeneous plant's cells, tissues or organs interact and interplay to form a complete organism. The process is not only regulated by the scion and rootstock, but also influenced by some external factors. It has become a hotspot research area in botany. Grafting can improve plant productivity and quality and help the plant adapt to environment. Understanding the mechanism of graft healing makes a great significance to grafting survival rate and the application of grafting technology in production. This paper reviewed the morphological process, physiological and biochemical mechanism of grafted healing as well as its molecular regulation and determinants, and proposed several directions for future research.
Tetrabromobisphenol A epoxy resin is widely used in the electronics and aerospace industries, but application is limited due to high costs. The aim of this study was to determine the effects of lignin and brominated lignin on thermal properties of epoxy resin. Lignin and brominated lignin were mixed with bisphenol A and reacted with epichlorohydrin to produce epoxy resin. Then, thermal properties of the epoxy resin were tested. Results showed that when the lignin content (M:M) was 10%, temperatures for mass loss were higher than that of bisphenol A epoxy resin (the initial temperature was 4.4℃ higher and the peak temperature was 68.9℃ higher), and the mass loss was 3.8% lower. Temperatures for mass loss of brominated lignin-bisphenol A epoxy resin (Br-LBEP) were higher than that of LBEP (initial temperature 112.2℃ higher and peak temperature 93.7℃ higher) with the mass loss being 2.1% lower. Thus, brominated lignin improved thermal properties and could be used instead of tetrabromobisphenol A to produce high thermal property epoxy resin.
To establish the efficient regeneration system and lay foundation for transgenic system of Sedum plumbizincicola in this research, the young leaves of S. plumbizincicola as explants, several factors affecting callus induction, bud differentiation, and plant regeneration were studied, and then a regeneration system was established. An MS medium supplemented with 300 mg·L-1 hydrolyzed casein was used as the basic medium. Different concentrations of hormone combinations was designed. Results showed that the best medium for leaf callus induction was the basic medium with 1.00 mg·L-1 2, 4-Dichlorophenoxyacetic acid (2, 4-D) and 0.30 mg·L-1 6-Benzylaminopurine (6-BA) added having a callus induction rate of 92.01%. The best medium for bud differentiation was the basic medium supplemented with 0.10 mg·L-1 2, 4-D and 1.00 mg·L-1 6-BA having a callus differentiation rate of 27.44%. A suitable medium for bud proliferation was the basic medium with 0.10 mg·L-1 2, 4-D and (0.50-1.00) mg·L-1 6-BA added. Also, a suitable rooting medium was the basic medium with 1.00-2.00 mg·L-1 3-indolebutyric acid (IBA) added. These findings laid a tissue culture foundation for the establishment of a transgenic system with S. plumbizincicola.
In order to reveal dynamic changes of volatile organic compounds (VOCs) released in different stages of Ruta graveolens, leaves and flowers were used as materials to determine the components, relative content, and releasing dynamics of VOCs using the methods of headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). Results showed 29 VOCs that were identified in different seasons of the year. The major VOCs released from leaves of R. graveolens were esters (11 components) and ketones (7 components). Components released from leaves over one year were the most in June (18 components) and the least in September (10 components). Relative content for esters was the most in June and the least in December, but for ketones was the most in December and the least in June. In the course of one day, VOC components were the order at the following daytime hours:12:00 > 10:00 > 14:00 > 16:00 > 18:00 > 8:00 > 20:00; values at 12:00 were maximum, mainly esters and ketones. Major components released from flowers (esters having 2-undecanone as the primary VOC) were much less than from leaves. The major components released from leaves and flowers all had medical and health care benefits. Thus, R. graveolens, an admirable ornamental plant, could be a healthy and aromatic plant for improving a landscape.