高氮营养增高厚果含笑叶片的叶黄素介导热耗散研究  

High-nitrogen Nutrition Enhances Xanthophyll-mediated Thermal Dissipation in Michelia lacei Leaves

作　　者：孙谷畴[1] 赵平[1] 

机构地区：[1]中国科学院华南植物研究所,广州510650

出　　处：《应用与环境生物学报》2007年第5期641-646,共6页Chinese Journal of Applied and Environmental Biology

基　　金：中国科学院知识创新工程重要方向项目(KSCX2-SW-133);国家自然科学基金基础青年基金项目(B类;No.30428022)~~

摘　　要：厚果含笑(Michelialacei)生长在供给6mmolL-1NO3-(高氮)和2mmolL-1NO3-(低氮)Hoagland溶液的盆栽土中,利用PAM-2100叶绿素荧光仪、Licor-6400LCF荧光叶室和WatersHPLC分别测定叶绿素a荧光参数和类胡萝卜素组分,研究氮营养对光系统II(PSII)光化效率和光或暗下热耗散过程的影响.结果表明,在自然光日进程中叶片的开启PSII反应中心的内在量子效率(Fv/Fm)随光辐射增强而降低.低氮叶片Fv/Fm较高氮叶片降低明显(P<0.05).低氮叶片表现较明显的光抑制现象,反映低氮叶片对光抑制比高氮叶片敏感.高氮叶片比低氮叶片有低的PSII光化效率(ΦPSⅡ,P<0.05).高氮叶片依赖光的ΔpH和叶黄素介导的热耗散效率(ΦNPQ)和光下热耗散速率(JNPQ)则较低氮叶片高(P<0.05),结果反映高氮营养增进光下热耗散效率和速率.高氮叶片的紫黄质(A)+玉米黄质(Z)和叶黄素循环色素的转换态(A+Z/V+A+Z)则较低氮叶片高(P<0.05).高氮叶片有较高光下热耗散(NPQ)和相应较高的(A+Z)或(A+Z/V+A+Z),叶片通过叶黄素循环色素以热的形式耗散过剩能;而低氮叶片表现高的总荧光淬灭和暗下热耗散.充足氮叶片有较低的光化效率,增高了光呼吸,并通过增强通过叶黄素循环色素的大量耗散过剩能.结果显示,过量氮输入将降低植物光能利用效率.The plants of Michelia lacei were grown in the composite soil supplied with 6 mmol L^-1 NO3^- （ high nigtrogen, HN） and 2 mmol L^-1 NO3^- （ low nigtrogen, LN） Hoagland solution. The effects of different nitrogen levels on photochemical efficiency in photosystem II （PSII） and thermal dissipation processes were studied by measuring chlorophyll fluorescence parameters through PAM-2100 module and Licor-6d00 LCF. Carotenoid composition was also analyzed with Waters HPLC. The results showed that the intrinsic quantum efficiency of open PSII reaction center （ Fv/Fm ） decreased as light irradiance increased under natural condition. Fv/Fm in LN （low nitrogen） leaves was significantly decreased compared with that in HN （high nitrogen） leaves, reflecting a higher sensitivity of photinhibition occurred in LN leaves. The HN leaves had a lower photochemical efficiency （ φPSⅡ ） than LN leaves （ P 〈 0.05 ）. A much higher φNPQ, namely, light-dependant △pH and xanthophylls-mediated thermal dissipation occurred in the HN leaves and a higher rate of thermal dissipation in the light （JNpQ） was found for the HN leaves. Besides, the higher thermal dissipation in the light （NPQ） occurred relating to the higher levels of （ A ＋ Z） and the conversion state of the xanthophylls cycle expressing as （ A ＋ Z/V ＋ A ＋ Z） in the HN leaves, implying that the excess irradiance not utilized by electron transport in the HN leaves was dissipated through the process of light dependant △pH and xantho- phylls-mediated thermal dissipation. The results showed that photochemical efficiency was decreased because of the N-replete condition in plants and the greater fraction of absorbed excess irradiance that was not utilized by electron transport and was dissipated by xanthophylls-mediated thermal dissipation process. The utilization efficiency of absorbed energy in plants would be decreased by import of the N-replete to plant vegetation.

关 键 词：高氮营养 光化效率 叶黄素介导热耗散 厚果含笑 

分 类 号：Q947[生物学—植物学]