遮荫对天女木兰光合特性及生长的影响

研究不同程度的遮荫(A:0,B:25.8%,C:61.3%,D:90.3%)对天女木兰光合特性及生长的影响。结果表明:天女木兰的地径、苗高和生物量均表现为B>A>C>D。天女木兰的光补偿点和光饱和点均较低,且随着遮荫程度的提高,其值以及暗呼吸速率均依次降低。天女木兰净光合速率日变化规律在不同的遮荫处理下均呈现双峰型曲线,有明显的光合"午休"现象,净光合速率日最大值为B>A>C>D。B处理是这4种遮荫处理中天女木兰生长最适宜的遮荫强度,适度遮荫可增强天女木兰叶片的光合作用,促进其生长。

Effects of Shading on the Photosynthetic Characteristics and Growth of Magnolia sieboldii

The effects of different shading treatments(A:0,B:25.8%,C:61.3%,D:90.3%)on the photosynthetic characteristics and growth of Magnolia sieboldii were examined.The results showed that the basal diameter,height and biomass at B treatment were higher than those at other shading treatments.The light compensation point(LCP),light saturation point(LSP) and dark respiration rate(DP)of the Magnolia sieboldii were at a low level,the value of which decreased with the increasing of shading degree.The daily variation of net photosynthetic presented a bimodal curve under four shading treatments.The net photosynthetic rate was B>A>C>D.It is obvious that B treatment can provide the most suitable condition for Magnolia sieboldii among four shading treatments.So we can conclude that moderate shading could increase the leaf photosynthesis and plant growth of Magnolia sieboldii.