光强和氮素对紫茎幼苗光合特性的影响  

Effects of light intensity and nitrogen treatments on photosynthetic characteristics of Stewartia sinensis seedlings

作　　者：张婷宇 张明如[1] 李清香 赵楠楠 万琦 蔡益杭 ZHANG Tingyu;ZHANG Mingru;LI Qingxiang;ZHAO Nannan;WAN Qi;CAI Yihang(College of Landscape and Architecture,Zhejiang A&F University,Hangzhou 311300,Zhejiang,China)

机构地区：[1]浙江农林大学风景园林与建筑学院,浙江杭州311300

出　　处：《浙江农林大学学报》2022年第6期1247-1256,共10页Journal of Zhejiang A&F University

基　　金：浙江省自然科学基金资助项目(LY18C160002);国家自然科学基金面上资助项目(31570611)。

摘　　要：【目的】研究紫茎Stewartia sinensis幼苗对不同光强和土壤氮素质量分数的光合生理生态适应差异性,筛选紫茎幼苗适宜的光强和氮素处理组合。【方法】选择1年生紫茎幼苗为试验材料,设置4个透光率分别为全光100.00%(L_(0))、轻度遮光(44.79±0.51)%(L1)、中度遮光(19.60±0.23)%(L2)、高度遮光(7.25±0.10)%(L3),3个施氮量分别为低氮0.2 g·kg^(−1)(N_(1))、高氮0.6 g·kg^(−1)(N_(2))和不施氮(N_(0)),经90 d处理测定不同光、氮处理下紫茎幼苗的光响应过程、光合色素质量分数和叶绿素荧光参数。【结果】光强、氮素及其交互作用对紫茎幼苗的光合色素质量分数和叶绿素荧光参数的影响均达显著水平(P<0.05)。紫茎幼苗的叶绿素a/b为2.0~2.5,光补偿点(L_(CP))为4.8~26.0μmol·m^(−2)·s^(−1),光饱和点(L_(SP))为571.3~931.4μmol·m^(−2)·s^(−1)。随着遮光程度的增加,紫茎幼苗的叶绿素和类胡萝卜素质量分数、初始荧光(F_(o))、最大荧光(F_(m))、表观量子效率(A_(QY))趋于增大,叶绿素a/b、类胡萝卜素/总叶绿素的比值下降,最大净光合速率(P_(max))、暗适应下光系统Ⅱ(PSⅡ)潜在活性(F_(v)/F_(o)、PSⅡ)最大光能转化效率(F_(v)/F_(m))和以吸收光能为基础的性能指数(P_(IABS))呈现先升高后降低的特点。随着施氮量的增加,紫茎幼苗P_(IABS)趋于增大,叶绿素a/b、F_(o)和F_(m)趋于减小。叶绿素和类胡萝卜素质量分数、P_(max)、A_(QY)呈现先升高后降低的特点。在L_(1)和L_(2)光强下,紫茎幼苗的净光合速率(P_(n))、气孔导度(G_(s))和蒸腾速率(T_(r))较高,且胞间二氧化碳摩尔分数(C_(i))较低,此时施用低氮对P_(n)、G_(s)和T_(r)有明显促进作用。L_(1)N_(1)的P_(max)相较L_(1)N_(0)增加了45.21%,L_(2)N_(1)的P_(n)和P_(max)均最高。【结论】紫茎幼苗在中度遮光和低氮处理下的光合能力最佳,在全光或高氮处理下会出现光合抑制现象。图1表6参34。[Objective]This study,with an investigation of the differences in the hotosynthetic hysiological and ecological adaptation of Stewartia sinensis seedlings to different light intensity and soil nitrogen content,is aimed to select combinations of light intensity and nitrogen treatment that are conducive to the cultivation of S.sinensis seedlings.[Method]With S.sinensis seedlings used as test materials,efforts were made to set four light intensity gradients,namely full light(L_(0)),light light(44.79±0.51)%(L_(1)),moderate light(19.60±0.23)%(L_(2)),high light(7.25±0.10)%(L_(3)),and three nitrogen application rates,i.e,low nitrogen 0.2 g·kg^(−1)(N_(1)),high nitrogen 0.6 g·kg^(−1)(N_(2))and no nitrogen application(N0)before the light response process,photosynthetic pigment mass fraction and chlorophyll fluorescence parameters were recorded and measured upon 90 d treatment.[Result]Light intensity,nitrogen and their interaction displayed significant effects on photosynthetic pigment and chlorophyll fluorescence of S.sinensis seedlings(P<0.05).Chl a/b values of S.sinensis seedlings varied from 2.0 to 2.5,the LSP of S.sinensis seedlings varied from 571.3 to 931.4μmol·m^(−2)·s^(−1) whereas LCP varied from 4.8 to 26.0μmol·m^(−2)·s^(−1).With the increase of shading degree,the Chl,Car,F_(o),F_(m),A_(QY) of S.sinensis seedlings tended to increase,the Chl a/b and Car/Chl tended to decrease while the P_(max),F_(v)/F_(o),F_(v)/F_(m) and PIABS increased first and then decreased.With the increase of nitrogen application rate,the PIABS of S.sinensis seedlings tended to increase,the Chl a/b,Fo and Fm tended to decrease and the Chl,Car,P_(max) and AQY increased first and then decreased;With L_(1) and L_(2) light intensity,Pn,Gs and Tr of S.sinensis seedlings were higher and Ci was lower and the application of low nitrogen significantly promoted Pn,Gs and Tr.The P_(max) of L_(1)N_(1) increased by 45.21%compared with L_(1)N_(0) with the Pn and P_(max) of L_(2)N_(1) being the highest.[Conclusion]S.sinensis seedlings

关 键 词：紫茎 光强 氮素 双因素控制试验 光响应 光合色素 叶绿素荧光 

分 类 号：S718.5[农业科学—林学]