遮光对不同基因型玉米光合特性的影响

采用盆栽试验,研究了遮光对4个基因型玉米光合特性的影响.结果表明:4个基因型玉米叶片的光饱和点、净光合速率(Pn)、电子传递速率(ETR)、光系统Ⅱ最大光化学效率(Fv/Fm)和实际光化学效率(ΦPSⅡ)均受光强的影响.遮光降低了玉米的光饱和点,苗期遮光处理豫玉2号和丹玉13分别在光量子通量密度(PFD)为1400μmol·m-2·s-1和1100μmol·m-2·s-1时达到饱和.遮光还降低了玉米的Pn、ETR、Fv/Fm和ΦPSⅡ,但不同基因型玉米表现不同,豫玉2号和掖单22的下降幅度较小,而丹玉13和掖单6号的下降幅度较大.

Effects of shading on photosynthetic characteristics of different genotype maize

A pot experiment with 4 genotype maize varieties showed that light intensity had strong effects on their leaf light saturation point, diurnal variation of net photosynthetic rate (Pn), estimated electron transport rate (ETR), maximal photochemical efficiency of PS II (Fv/Fm), and actual photochemical efficiency of PSII (Phi(PS II)). Under shading, the light saturation point of test varieties decreased. For example, shading at seedling stage made the varieties Yuyu 2 and Danyu 13 get to light-saturated when the photon flux density (PFD) was 1400 micromol.m(-2).s(-1) and 1100 micromol.m(-2).s(-1), respectively. Shading also decreased the Pn, ETR, Fv/Fm and Phi(PS II), but the responses differed with the varieties. The decrement of these parameters was remarkably lesser for Yuyu 2 and Yedan 22 than for Danyu 13 and Yedan 6.