Background:The photosynthetic parameters of cotton plants may be modified by the timing of film removal during their growing period.This study was undertaken during 2015-2017 in Xinjiang,China,to determine to what ext...Background:The photosynthetic parameters of cotton plants may be modified by the timing of film removal during their growing period.This study was undertaken during 2015-2017 in Xinjiang,China,to determine to what extent the film mulching removal time,1 and 10 days before the first irrigation and 1 day before the second irrigation after seedling emergence,influenced cotton's photosynthetic characteristics.The control group(CK)was film-mulched throughout the growth stages.Results:The results suggested the following:(1)Removing mulching-film within 50 days since seedling emergence had adverse effects on soil temperature and moisture.(2)Film-removal before the first or second irrigation after emergence improved the net photosynthetic rate in cotton's later flowering stage and its transpiration rate in mid and later flowed ng stages while enhancing the actual electron transport rate(ETR)and maximum electron transfer rate(ETRmax)between cotton photosystems I and II.(3)Film-removal treatment also increased cotton plants'toleranee to high irradiation after emergence,the trend was more pronounced in the early flowering stage in wetter years.(4)Leaf area index(LAI)of cotton was reduced in the film-removal treatment for which the least accumulation of dry matter occurred in a drought year(i.e.,2015).(5)Film removal caused a yield decrease in the dry year(2015),and the earlier the film was removed,the more seriously the yield decreased.Removing mulching film before the second irrigation could increase the yield of XLZ42 in the rainy year(2016)and the normal rainfall year(2017).Early film removal can in crease the yield of XLZ45 in the rainy year(2016).Conclusions:Collectively,our stud/s experimental results indicate that applying mulch film removal at an appropriate,targeted time after seedling emerge nee had no adverse effects on soil moisture and temperature,and improved the photosy nthetic performance of cotton,thus in creased cotton yield and fiber quality,but no significant difference was reached.展开更多
凋落物是土壤呼吸的主要碳源,日益增加的大气氮沉降通过改变森林凋落物的输入与分解影响土壤呼吸。为揭示氮沉降及凋落物管理对森林土壤呼吸及其组分的影响,以贵州省国有扎佐林场15年生柳杉人工林为研究对象,设置4个氮添加处理:对照(CK,...凋落物是土壤呼吸的主要碳源,日益增加的大气氮沉降通过改变森林凋落物的输入与分解影响土壤呼吸。为揭示氮沉降及凋落物管理对森林土壤呼吸及其组分的影响,以贵州省国有扎佐林场15年生柳杉人工林为研究对象,设置4个氮添加处理:对照(CK,0 gN m^(-2)a^(-1))、低氮(LN,15 gN m^(-2)a^(-1))、中氮(MN,30 gN m^(-2)a^(-1))和高氮(HN,60 gN m^(-2)a^(-1)),并在每种氮添加处理下设置去除凋落物和保留凋落物两种处理,于2021年3月—2022年2月利用LI⁃8100测定土壤呼吸速率,并分析氮添加及凋落物处理对土壤呼吸速率影响,确定影响土壤呼吸速率变化的主要因子。结果表明:氮添加和去除凋落物处理没有改变土壤呼吸速率的时间变化,土壤呼吸速率月均最大值出现在7月,月均最小值出现在2月。氮添加对土壤呼吸速率无显著影响(P>0.05),除CK外,去除凋落物处理会显著降低土壤呼吸速率(P<0.05)。凋落物对土壤总呼吸速率的贡献率为8.6%—28.5%,且LN处理下凋落物对土壤呼吸速率的贡献率最大。土壤呼吸速率与5 m土壤温度呈显著指数相关(P<0.01),与5 cm土壤湿度呈显著负线性相关(P<0.01)。土壤温度解释了土壤呼吸速率变异的58.5%—79.5%,土壤湿度解释了土壤呼吸速率变异的26.4%—39.5%,以土壤温度和湿度构建的双变量模型拟合效果均好于单因子模型,土壤温湿度共同解释土壤呼吸速率变异的59.1%—85.8%。结论表明在大气氮沉降增加的背景下,温度是影响土壤呼吸的主要因素,凋落物管理是调控土壤呼吸的关键过程。展开更多
Micrographs of lychee pericarp and pulp during microwave vacuum drying were tested and analyzed in order to illuminate the microstructure change of lychee and effect of the change on moisture removing in lychee.The re...Micrographs of lychee pericarp and pulp during microwave vacuum drying were tested and analyzed in order to illuminate the microstructure change of lychee and effect of the change on moisture removing in lychee.The results showed that the pericarp consisted of three parts:outer layer with cuticle,inter layer and inner layer.Outer layer and inter layer cells are easily destroyed than inner layer because of small and intact inner layer cells.Furthermore,micrographs showed that the moisture content of pulp keep constant with the temperature increasing at first 40 min due to the inner layer cells prevent the moisture removing from pulp.The long tubular structure of pulp cell would become break and lost over time,because the intercellular spaces reduced and the moisture removing was slow down in pulp.Meanwhile,the microstructure of lychee dried with temperature control was better than that without temperature control.展开更多
基金the special fund for scientific research into non-profit industries(agriculture,grant no.201503120).
文摘Background:The photosynthetic parameters of cotton plants may be modified by the timing of film removal during their growing period.This study was undertaken during 2015-2017 in Xinjiang,China,to determine to what extent the film mulching removal time,1 and 10 days before the first irrigation and 1 day before the second irrigation after seedling emergence,influenced cotton's photosynthetic characteristics.The control group(CK)was film-mulched throughout the growth stages.Results:The results suggested the following:(1)Removing mulching-film within 50 days since seedling emergence had adverse effects on soil temperature and moisture.(2)Film-removal before the first or second irrigation after emergence improved the net photosynthetic rate in cotton's later flowering stage and its transpiration rate in mid and later flowed ng stages while enhancing the actual electron transport rate(ETR)and maximum electron transfer rate(ETRmax)between cotton photosystems I and II.(3)Film-removal treatment also increased cotton plants'toleranee to high irradiation after emergence,the trend was more pronounced in the early flowering stage in wetter years.(4)Leaf area index(LAI)of cotton was reduced in the film-removal treatment for which the least accumulation of dry matter occurred in a drought year(i.e.,2015).(5)Film removal caused a yield decrease in the dry year(2015),and the earlier the film was removed,the more seriously the yield decreased.Removing mulching film before the second irrigation could increase the yield of XLZ42 in the rainy year(2016)and the normal rainfall year(2017).Early film removal can in crease the yield of XLZ45 in the rainy year(2016).Conclusions:Collectively,our stud/s experimental results indicate that applying mulch film removal at an appropriate,targeted time after seedling emerge nee had no adverse effects on soil moisture and temperature,and improved the photosy nthetic performance of cotton,thus in creased cotton yield and fiber quality,but no significant difference was reached.
文摘凋落物是土壤呼吸的主要碳源,日益增加的大气氮沉降通过改变森林凋落物的输入与分解影响土壤呼吸。为揭示氮沉降及凋落物管理对森林土壤呼吸及其组分的影响,以贵州省国有扎佐林场15年生柳杉人工林为研究对象,设置4个氮添加处理:对照(CK,0 gN m^(-2)a^(-1))、低氮(LN,15 gN m^(-2)a^(-1))、中氮(MN,30 gN m^(-2)a^(-1))和高氮(HN,60 gN m^(-2)a^(-1)),并在每种氮添加处理下设置去除凋落物和保留凋落物两种处理,于2021年3月—2022年2月利用LI⁃8100测定土壤呼吸速率,并分析氮添加及凋落物处理对土壤呼吸速率影响,确定影响土壤呼吸速率变化的主要因子。结果表明:氮添加和去除凋落物处理没有改变土壤呼吸速率的时间变化,土壤呼吸速率月均最大值出现在7月,月均最小值出现在2月。氮添加对土壤呼吸速率无显著影响(P>0.05),除CK外,去除凋落物处理会显著降低土壤呼吸速率(P<0.05)。凋落物对土壤总呼吸速率的贡献率为8.6%—28.5%,且LN处理下凋落物对土壤呼吸速率的贡献率最大。土壤呼吸速率与5 m土壤温度呈显著指数相关(P<0.01),与5 cm土壤湿度呈显著负线性相关(P<0.01)。土壤温度解释了土壤呼吸速率变异的58.5%—79.5%,土壤湿度解释了土壤呼吸速率变异的26.4%—39.5%,以土壤温度和湿度构建的双变量模型拟合效果均好于单因子模型,土壤温湿度共同解释土壤呼吸速率变异的59.1%—85.8%。结论表明在大气氮沉降增加的背景下,温度是影响土壤呼吸的主要因素,凋落物管理是调控土壤呼吸的关键过程。
基金the National Natural Science Foundation of China(No.31201399)Shenzhen Technology Innovation Program(No.JCYJ20140508155916427)Program for Science&Technology Innovation Talents in Universities of Henan Province(No.14HASTIT023)for the financial support of materials and the equipment.
文摘Micrographs of lychee pericarp and pulp during microwave vacuum drying were tested and analyzed in order to illuminate the microstructure change of lychee and effect of the change on moisture removing in lychee.The results showed that the pericarp consisted of three parts:outer layer with cuticle,inter layer and inner layer.Outer layer and inter layer cells are easily destroyed than inner layer because of small and intact inner layer cells.Furthermore,micrographs showed that the moisture content of pulp keep constant with the temperature increasing at first 40 min due to the inner layer cells prevent the moisture removing from pulp.The long tubular structure of pulp cell would become break and lost over time,because the intercellular spaces reduced and the moisture removing was slow down in pulp.Meanwhile,the microstructure of lychee dried with temperature control was better than that without temperature control.
