低氮对不同茶树品种叶绿素荧光特性的影响

Effects of Chlorophyll Fluorescence Parameters of Different Tea Cultivars in Response to Low Nitrogen

叶绿素荧光参数经常用来评价植物抗逆胁迫强弱,反应植物胁迫的生理状态等。为灵敏检测和判断茶树品种低氮胁迫的差异,科学指导施肥,本研究以前期筛选的相对氮高效茶树品种黄旦与相对氮敏感茶树品种本山为试验材料,检测不同供氮处理下叶绿素荧光参数及生物量的变化,结果发现低氮条件下茶树叶片氮含量显著偏低,但该条件下黄旦品种叶片氮含量明显高于本山品种;低氮条件下茶树叶片最小荧光F_o、调节性能量耗散的量子产额Y(NPQ)、非光化学淬灭系数(NPQ)、非调节性能量耗散的量子产额Y(NO)等显著增加,黄旦品种在低氮条件下F_o、Y(NPQ)、Y(NO)及NPQ参数都要小于本山品种;而参数最大荧光(F_m)、光系统Ⅱ最大光合效率(F_v/F_m)、光化学淬灭系数(qP与qL)、实际光合效率Y(Ⅱ)显著下降,其中本山品种低氮下明显小于黄旦。总之,氮高效茶树品种黄旦能减缓低氮胁迫对植株造成的损害,并维持相对较高的光合效率,保证了低氮条件下有较高的产量。

Chlorophyll fluorescence parameters are often used to evaluate stress status and plant physical response to stresses.To explore guidelines for nitrogen fertilization,nitrogen deficiency degree should be measured and estimated sensitively.Therefore,items including individual plant dry matter,nitrogen content and fluorescence parameters of leaves were measured among tea cultivars with different nitrogen use efficiencies.The dry matter of roots,stems,leaves and nitrogen content in leaves were declined sharply under low nitrogen stress.Compared with the low nitrogen sensitive tea cultivar'Benshan',the root,stem and leaf dry weights(DW)of'Huangdan'were higher under low nitrogen stress.Fo,Y(NPQ),non-photochemical quenching coefficients(NPQ)and Y(NO)increased under low nitrogen,and the fluorescence parameters of'Benshan'under low nitrogen were higher than Huangdan.The maximum(Fm),primary maximum photochemical efficiency of PSⅡ(Fv/Fm),actual photosynthetic efficiency Y(Ⅱ)and coefficient of photochemical quenching(qP and qL)decreased under low nitrogen,and the fluorescence parameters of'Benshan'under low nitrogen were lower than those of'Huangdan'.The relative high nitrogen-utility tea cultivar can reduce the damage caused by the low nitrogen stress and maintain a relatively high photosynthetic efficiency.Therefore,tea cultivar with relative high nitrogen-utility had higher yields than cultivar with low nitrogen-utility under low nitrogen stress.