遮阴处理对金蒲桃生长量及光合参数的影响

Effects of Shading on Growth and Response Characteristics of Photosynthesis in Xanthostemon chrysanthus

以2 a生金蒲桃(Xanthostemon chrysanthus)幼苗为材料,研究了全光照,50%遮阴,70%遮阴,90%遮阴4种遮阴处理对金蒲桃生长特性、生物量分配、光合生理变化的影响,结果表明:与自然光全处理对比,遮光极显著(P<0.01)地抑制了金蒲桃幼苗生物量的积累,遮光处理组叶片数量减少,叶生物量比下降,茎生物量比增加;光补偿点、光饱和点、暗呼吸速率和最大光合速率降低,光能利用效率低于全光照叶,强光下遮阴叶的净光合速率保持稳定。上述结果说明:遮阴处理后,金蒲桃在生长特性、生物量分配和光合参数上表现出对遮阴弱光的适应,表明金蒲桃是一种能广泛应用于各种光照条件的优良景观树种。

The growth characteristics,biomass allocation and photosynthetic physiological changes of2-year-old Xanthostemon chrysanthus were examined with4shade gradients:full natural light(FL),50%shading(LS),70%shading(MS),90%shading(HS).The results showed that compared with FL,shading inhibited thebiomass accumulation of X.chrysanthus extremely significantly.Shading also reduced the leaf number and leafmass ratio.However,stem mass ratio increased under shading condition.With shading treatment,plants had lowerlight-compensation point,light-saturation point,dark photosynthetic rate and maximum photosynthesis rate,andphotosynthetic rate of light-saturation was significantly lower.When given strong light,the net photosynthetic rateof the plants under irradiation shade remained stable.We concluded that X.chrysanthus had the ability to adjust toshade in growth characteristics,biomass allocation,characteristics of photosynthetic.It is showed that X.chrysanthusis a good landscape tree species that could be widely used in various light conditions.