[Objective] The aim was to explore effects of soil moisture on dry matter accumulation and distribution and growth of kai-lan. [Method] In the context of the same irrigation frequency, the influence of irrigation maxi...[Objective] The aim was to explore effects of soil moisture on dry matter accumulation and distribution and growth of kai-lan. [Method] In the context of the same irrigation frequency, the influence of irrigation maximum was researched on growth rate, net assimilation rate, and dry matter distribution of kai-lan. [Result] The results showed that regulation on soil moisture extremely significantly affected accumulation of photosynthate. When soil moisture was insufficient, the growth term from seedling to mature extended and growth rate declined sharply. Besides, the growth term was of extremely significant negative correlation with growth rate. Meanwhile,leaf assimilation rate decreased considerably. For example, when soil moisture was65%, distribution of dry matter in plant organs tended to be rational. [Conclusion]Deficit irrigation would significantly lower growth rate, and improve dry matter distribution in organs and economic yield and quality of kai-lan.展开更多
Conversions from rural to urban land uses have the potential to greatly modify soil phosphorus （P） levels. Soils in shrubs, Masson pine forest, conifer and broadleaf mixed forest, evergreen broadleaved forest and ba...Conversions from rural to urban land uses have the potential to greatly modify soil phosphorus （P） levels. Soils in shrubs, Masson pine forest, conifer and broadleaf mixed forest, evergreen broadleaved forest and bamboo forest in the mid-subtropical region along an urban-rural gradient in Nanchang City, southern China, were analyzed for total P and P fractions using the modified Hedley P sequential fractionation method. Results show that the topsoil total P and total exactable P concentrations were significantly higher in the urban area （0.71 g·kg^-1 and 378.50 mg·kg^-1, respectively） than in the suburban （0.30 g·kg^-1 and 150.74 mg·kg^-1, respectively） and rural areas （0.31 g·kg^-1 and 147.38 mg·kg^-1, respectively） （p〈0.05）. Among the five P fractions of resin-P, NaHCO3-P NaOH-P, Sonication-P and HCI-P, the relative abundance of HCl-P in urban forest soils （36%） was the highest and also significantly higher than in suburban （8%） and rural soils （6%）, while NaOH-P was the dominant form in suburban （41%） and rural soils （50%）. Phosphorus accumulation in the urban soils could affect the cycle of P in urban forest systems, particularly the HCl-P fraction that might rapidly enrich aquatic systems in urban areas.展开更多
[Objective] The aim was to analyze biomass accumulation, degradation and saccharification characteristics of Triarrhena lutarioriparia. [Method] With Triarrhena lutarioriparia as materials, samples were collected from...[Objective] The aim was to analyze biomass accumulation, degradation and saccharification characteristics of Triarrhena lutarioriparia. [Method] With Triarrhena lutarioriparia as materials, samples were collected from April 2012 to November 2012 to explore monthly biomass changes and degradation and saccharification of Triarrhena lutarioriparia. [Result] Plant height was improving upon time; holocellulose and cellulose contents were increasing with dry weight of shoot system increasing and achieved the peak at 78.1% and 40% in September. It can be concluded that NaOH pre-treatment efficiency is better, when Triarrhena lutarionparia was treated with 2% NaOH at 100 ℃ for 20 min and reducing sugar yield achieved 178,42 mg/g. [Conclusion] Triarrhena lutarioriparia can be materials for ethyl alcohol production and the optimal harvest time is from middle September to middle October.展开更多
The pollution characteristics of Pb, Cd, Zn, Cu and Ni in soil of lead-zinc mining area were studied. The results indicate that the contamination degree followed the sequence of Cd〉Pb〉Zn〉Ni〉Cu and concentrations o...The pollution characteristics of Pb, Cd, Zn, Cu and Ni in soil of lead-zinc mining area were studied. The results indicate that the contamination degree followed the sequence of Cd〉Pb〉Zn〉Ni〉Cu and concentrations of Pb, Cd and Zn exceeded corresponding limits of the Chinese National Soil Environmental Quality Standard III. The soil was extremely polluted by Cd（Iego=5.26）, moderately to heavily polluted by Zn（Iego=2.38）, heavily to extremely polluted by Pb（Iego=4.13）. The results of BCR three-step sequential extraction procedure show that the active Cd, Pb and Zn were relatively high and might exert adverse effects on the plants grown in the soil, while Cu and Ni existed in soil with a relatively stable form. Potential ecological risk results indicate that soils were engaging in a high potential ecological risk by pollution of Cd and should be given rise to concern.展开更多
Aim To study the theory and method for the prediction of service life of solid rocket propellant grain. Methods With the aid of discontiguous diagnostic technology and method of accumulated damage using accelerated...Aim To study the theory and method for the prediction of service life of solid rocket propellant grain. Methods With the aid of discontiguous diagnostic technology and method of accumulated damage using accelerated aging or heat air oven, the aging isotherms for void content versus aging time were determined. According to the principle of time temperature equivalence the viscoelastic master curve for the prediction of service life were obtained. Results and Conclusion The service life of HMX CMDB solid rocket propellant grain were obtained. Because the critical storage life is measured, the accuracy of predicting the service life of the grain has been increased greatly.展开更多
Seasonal dynamics of above- and belowground biomass and nutrient characteristics （nitrogen, carbon, and phosphorus） of Carex lasiocarpa were investigated in the typical wetland of Sanjiang Plain, China from May 2007...Seasonal dynamics of above- and belowground biomass and nutrient characteristics （nitrogen, carbon, and phosphorus） of Carex lasiocarpa were investigated in the typical wetland of Sanjiang Plain, China from May 2007 to September 2008. The results show that the changes of aboveground biomass during the growing season are best described by the twice function curve model, whereas the changes of belowground biomass follow the exponential increase curve model. Both the organic carbon contents in the above- and belowground plant parts show significant positive linear correlations with the growing time, and the coefficients R2 are 0.983 and 0.746, respectively. The carbon accu-mulations of the above- and belowground plant parts during the growing season show the same dynamics as those of the biomass. However, the nitrogen contents and accumulation in C. lasiocarpa aboveground and belowground parts show exponential increase during the growing season. The dynamics of C. lasiocarpa phosphorus contents follows the twice function curve model, whereas the accumulation of phosphorus shows the linear increase. The ratios of C/N in different parts of C. lasiocarpa fit the negative linear relations with total nitrogen content in the growing season. Moreover, the ratios of C/P in C. lasiocarpa plant also fit the negative linear relations with total phosphorus content. The results show that nitrogen is the primary limiting nutrient for C. lasiocarpa growth as compared with carbon and phosphorus.展开更多
基金Supported by Applied Research and Demonstration of Soil Moisture Measurementsbased Automatic Irrigation Technology in Vegetable Production(2015A020209068)+2 种基金Guangdong Province Science and Technology ProjectHigh-efficient Cultivation and Nonpoint Source Pollution Control in Typical Vegetable Fields-Farmland Comprehensive Treatment Technology Plan on Chemical Fertilizer Nonpoint Source Pollution(201502103)Special Fund for Agro-scientific Research in the Public Interest~~
文摘[Objective] The aim was to explore effects of soil moisture on dry matter accumulation and distribution and growth of kai-lan. [Method] In the context of the same irrigation frequency, the influence of irrigation maximum was researched on growth rate, net assimilation rate, and dry matter distribution of kai-lan. [Result] The results showed that regulation on soil moisture extremely significantly affected accumulation of photosynthate. When soil moisture was insufficient, the growth term from seedling to mature extended and growth rate declined sharply. Besides, the growth term was of extremely significant negative correlation with growth rate. Meanwhile,leaf assimilation rate decreased considerably. For example, when soil moisture was65%, distribution of dry matter in plant organs tended to be rational. [Conclusion]Deficit irrigation would significantly lower growth rate, and improve dry matter distribution in organs and economic yield and quality of kai-lan.
基金funded by the National Natural Science Foundation of China(No.3060047&30960311)Natural Science Foundation of Jiangxi Provinces(No.2007GQN1935)
文摘Conversions from rural to urban land uses have the potential to greatly modify soil phosphorus （P） levels. Soils in shrubs, Masson pine forest, conifer and broadleaf mixed forest, evergreen broadleaved forest and bamboo forest in the mid-subtropical region along an urban-rural gradient in Nanchang City, southern China, were analyzed for total P and P fractions using the modified Hedley P sequential fractionation method. Results show that the topsoil total P and total exactable P concentrations were significantly higher in the urban area （0.71 g·kg^-1 and 378.50 mg·kg^-1, respectively） than in the suburban （0.30 g·kg^-1 and 150.74 mg·kg^-1, respectively） and rural areas （0.31 g·kg^-1 and 147.38 mg·kg^-1, respectively） （p〈0.05）. Among the five P fractions of resin-P, NaHCO3-P NaOH-P, Sonication-P and HCI-P, the relative abundance of HCl-P in urban forest soils （36%） was the highest and also significantly higher than in suburban （8%） and rural soils （6%）, while NaOH-P was the dominant form in suburban （41%） and rural soils （50%）. Phosphorus accumulation in the urban soils could affect the cycle of P in urban forest systems, particularly the HCl-P fraction that might rapidly enrich aquatic systems in urban areas.
基金Supported by National High-tech R&D Program of China[(863 Program)2012AA-101804]Hunan Natural Science Foundation(12JJ3027)~~
文摘[Objective] The aim was to analyze biomass accumulation, degradation and saccharification characteristics of Triarrhena lutarioriparia. [Method] With Triarrhena lutarioriparia as materials, samples were collected from April 2012 to November 2012 to explore monthly biomass changes and degradation and saccharification of Triarrhena lutarioriparia. [Result] Plant height was improving upon time; holocellulose and cellulose contents were increasing with dry weight of shoot system increasing and achieved the peak at 78.1% and 40% in September. It can be concluded that NaOH pre-treatment efficiency is better, when Triarrhena lutarionparia was treated with 2% NaOH at 100 ℃ for 20 min and reducing sugar yield achieved 178,42 mg/g. [Conclusion] Triarrhena lutarioriparia can be materials for ethyl alcohol production and the optimal harvest time is from middle September to middle October.
基金Project(2012FJ1010)supported by the National Science and Technology Major Project,ChinaProject(2012BAC09B04)supported by the National"Twelfth Five-Year"Plan for Science&Technology,ChinaProject(2012AA06202)supported by the National High-tech Research and Development Program of China
文摘The pollution characteristics of Pb, Cd, Zn, Cu and Ni in soil of lead-zinc mining area were studied. The results indicate that the contamination degree followed the sequence of Cd〉Pb〉Zn〉Ni〉Cu and concentrations of Pb, Cd and Zn exceeded corresponding limits of the Chinese National Soil Environmental Quality Standard III. The soil was extremely polluted by Cd（Iego=5.26）, moderately to heavily polluted by Zn（Iego=2.38）, heavily to extremely polluted by Pb（Iego=4.13）. The results of BCR three-step sequential extraction procedure show that the active Cd, Pb and Zn were relatively high and might exert adverse effects on the plants grown in the soil, while Cu and Ni existed in soil with a relatively stable form. Potential ecological risk results indicate that soils were engaging in a high potential ecological risk by pollution of Cd and should be given rise to concern.
文摘Aim To study the theory and method for the prediction of service life of solid rocket propellant grain. Methods With the aid of discontiguous diagnostic technology and method of accumulated damage using accelerated aging or heat air oven, the aging isotherms for void content versus aging time were determined. According to the principle of time temperature equivalence the viscoelastic master curve for the prediction of service life were obtained. Results and Conclusion The service life of HMX CMDB solid rocket propellant grain were obtained. Because the critical storage life is measured, the accuracy of predicting the service life of the grain has been increased greatly.
基金This research was supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (No.KZCX2–YW–309)the Major State Basic Research Development Program of China (973 Program No. 2004CB418507)
文摘Seasonal dynamics of above- and belowground biomass and nutrient characteristics （nitrogen, carbon, and phosphorus） of Carex lasiocarpa were investigated in the typical wetland of Sanjiang Plain, China from May 2007 to September 2008. The results show that the changes of aboveground biomass during the growing season are best described by the twice function curve model, whereas the changes of belowground biomass follow the exponential increase curve model. Both the organic carbon contents in the above- and belowground plant parts show significant positive linear correlations with the growing time, and the coefficients R2 are 0.983 and 0.746, respectively. The carbon accu-mulations of the above- and belowground plant parts during the growing season show the same dynamics as those of the biomass. However, the nitrogen contents and accumulation in C. lasiocarpa aboveground and belowground parts show exponential increase during the growing season. The dynamics of C. lasiocarpa phosphorus contents follows the twice function curve model, whereas the accumulation of phosphorus shows the linear increase. The ratios of C/N in different parts of C. lasiocarpa fit the negative linear relations with total nitrogen content in the growing season. Moreover, the ratios of C/P in C. lasiocarpa plant also fit the negative linear relations with total phosphorus content. The results show that nitrogen is the primary limiting nutrient for C. lasiocarpa growth as compared with carbon and phosphorus.
