遮阴对红砂幼苗生长及光合特性的影响

Influence of shading on growth and photosynthetic characteristics of Reaumuria soongorica seedlings

以1年生红砂(Reaumuria soongorica)幼苗为研究对象,以自然光强为对照,采用透光膜设置6个光强梯度0%(L0)、15%(L1)、30%(L2)、40%(L3)、60%(L4)、80%(L5),探讨了不同遮光处理对红砂幼苗生物量积累和光合特性影响。测定其生长指标及光合指标,筛选适合红砂幼苗生长的光强范围。结果表明:1)轻度遮光(遮光度15%)红砂幼苗的苗高增长率、生物量积累、叶绿素含量、Fv/Fm、ΦPSII、ETR、净光合速率和水分利用效率均高于对照。2)正常光照处理(遮光度0%)红砂幼苗的类胡萝卜素含量、NPQ、胞间CO_(2)浓度(Ci)及蒸腾速率(Tr)最高。3)随遮光强度的增大,生长及光合指标均呈现先增加后下降的趋势,由高到低依次是L1>L0>L2>L3>L4>L5。4)综合所有指标表现,15%遮光度更具有促进红砂幼苗生长和光合作用的潜力。

The effects of different shading treatments on biomass accumulation and photosynthetic characteristics of one-year-old Reaumuria soongorica seedlings were studied with 6 light intensity gradients 0%(L0),15%(L1),30%(L2),40%(L3),60%(L4)and 80%(L5)in light transmittance film.The growth index and photosynthetic index were measured,and the light intensity range suitable for the growth of R.soongorica seedlings was screened.The results showed that:1)The seedling height growth rate,biomass accumulation,chlorophyll content,F_v/F_m,Φ_(PSII),ETR,net photosynthetic rate and water use efficiency of R.soongorica seedlings under light shading(15%shading)were higher than those of control.2)The carotenoid content,NPQ,intercellular CO_2 concentration(C_i)and transpiration rate(T_r)of R.soongorica seedlings treated with normal light(0%shading)were the highest.3)With the increase of shading intensity,the growth and photosynthetic indexes increased firstly and then decreased,and the order from high to low was L1L0L2L3L4L5.4)All indexes showed that 15%shading had the potential to promote the growth and photosynthesis of R.soongorica seedlings.