摘要
采用盆栽土培的方法,研究了不同施氮量(对照N00 kg N/hm2、低氮NL96 kg N/hm2、中氮NM288 kg N/hm2、高氮NH480kg N/hm2)对麻疯树幼苗生长、叶片气体交换及叶绿素荧光参数的影响。结果表明,麻疯树幼苗叶片氮含量、可溶性蛋白含量、株高、地径、叶片数量、叶面积、根长、各组分生物量、叶片净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和水分利用效率(WUE)均随施氮量的增加先升高后降低,NM处理下麻疯树幼苗长势最好,各气体交换参数值最高;施氮对麻疯树地上部分的促进作用远大于地下部分,施氮后根冠比显著降低;此外,麻疯树叶绿素含量、PSⅡ最大光化学量子产量(Fv/Fm)、PSⅡ有效量子产量(F′v/F′m)、PSⅡ实际光化学效率(ΦPSⅡ)、电子传递速率(ETR)和光化学淬灭系数(qP)均随施氮量的增加而升高,非光化学淬灭系数(NPQ)随施氮量增加而降低。适量施氮可通过增强叶绿体光化学活性、气孔导度和羧化能力而提高麻疯树幼苗的光合能力,促进生长;过高施氮对麻疯树幼苗光合与生长的促进效应降低。试验条件下,当年生麻疯树幼苗的最适施氮量为288 kg N/hm2。
Nitrogen（N） is an important component of chlorophyll,protein,nucleic acid,and some hormones in plant,it also controls the growth and development of plant in many ecosystems.N availability has been recognized as a key constraint to plant growth.The N demand of plant and corresponding N application availability is becoming the research focus of plant nutritionists and physiologists.Jatropha curcas L.is an potential woody oil species which wildly distributed in south China.However,the effects of nitrogen supply on growth and photosynthesis of J.curcas are poorly understood.Whether N application on seedling stage can promote the survival and growth of J.curcas at dry and poor conditions have certainly became a key problem for its extensive cultivation.In the present study,the characteristics of growth and leaf photosynthesis of J.curcas seedlings with different N supply levels were investigated.The experiment was conducted in greenhouse from May 2009 to September 2009.On May 1st,J.curcas seeds were sowed in plastic pot（diameter 27 cm,height 22 cm）.Twenty four such pots were prepared with four different N application rates（Control N0： 0 kg N/hm2;Low nitrogen NL： 96 kg N/hm2;Medium nitrogen NM： 288 kg N/hm2;High nitrogen NH： 480 kg N/hm2）.After two months of treatment,morphological and biomass indices of seedlings,leaf gas exchange,chlorophyll fluorescence and some biochemical parameters were determined.The results showed that the content of leaf N,soluble protein,plant height,biomass of different components,net photosynthetic rate（Pn）,stomatal conductance（Gs）,transpiration rate（Tr） and water use efficiency（WUE） increased when N supply increased from 0 kg N/hm2 to 288 kg N/hm2,and then decreased when N supply reached 480 kg N/hm2.The growth vigor of J.curcas with NM treatment was the best and all measured gas exchange parameters was the highest among all the four treatments.The promoting effect of N application on the above-ground biomass accumulation was much stronger than that on the under-ground one.N applications significantly decreased the root-shoot ratio.In addition,the leaf chlorophyll content,maximum quantum yield of PSⅡ photochemistry（Fv/Fm）,effective quantum yield of PSⅡphotochemistry（F′v/F′m）,actual photochemistry efficiency of PSⅡ（ΦPSⅡ）,electron transport rate（ETR） and photochemical quenching values（qP） increased with N application rate,while the non-photochemical quenching values（NPQ） exhibited a converse tendency.Results suggest that when J.curcas grows on the site with N deficiency condition,increasing nitrogen supply can promote its growth of root,shoot and leaf,and also enhance its photosynthetic capacity by improving photochemistry quantum efficiency of PSⅡ,Gs and carboxylation efficiency.While the NH treatment may have exceeded the optimum N level for J.curcas seedlings.In this study,the optimum N application rate for J.curcas seedlings was 288 kg N/hm2.
出处
《生态学报》
CAS
CSCD
北大核心
2011年第17期4977-4984,共8页
Acta Ecologica Sinica
基金
中日技术合作四川省示范林营造项目(JICA)
四川农业大学2008年国家级大学生创新性实验计划项目(2008-17),四川农业大学优秀硕士学位论文培育基金资助
关键词
施氮
麻疯树
生长
气体交换参数
叶绿素荧光参数
nitrogen
Jatropha curcas
growth
gas exchange parameter
chlorophyll fluorescence parameter
