不同地表覆盖方式对胡杨幼苗光合特性的影响及评价

为筛选对胡杨幼苗生长有效的地表覆盖物。以1年生胡杨幼苗为试材,设置覆膜(T1)、覆草苫子(T2)、覆沙(T3)和裸地(CK)共4种处理,利用相关性分析和隶属函数值法全面评价3种地表覆盖物对植株产生的效果。结果表明:T1、T2、T3处理均显著提高了不同月份的土壤含水率(P<0.05),平均土壤含水率较CK分别提高了26.1%、27.9%和23.5%;各覆盖均显著提高了成活率、株高及地径的生长,T2增长幅度最大;各覆盖均显著提高了叶片净光合速率(P n)、气孔导度(G s)、蒸腾速率(T r)(P<0.05),生长初期T1值最大,生长中后期T2值最大;T2处理的最大净光合速率(P max)、光饱和点(L SP)最大,光补偿点(L CP)和暗呼吸速率(R d)最低;各覆盖对水分利用效率(W UE)和表观量子效率(A QY)影响较小;植株生长与土壤含水率、P n、G s、P max、L SP呈极显著正相关(P<0.01),综合效果由强到弱顺序为T2、T3、T1、CK。覆草苫子较适宜在胡杨幼苗栽植过程中应用推广。

Effects of Different Land Cover on Photosynthetic Characteristics of Populus euphratica Seedlings and Evaluation

To screen the surface coverings effective for the growth of Populus euphratica seedlings,with 1-a P.euphratica seedlings,four treatments of film(T1),straw mat(T2),sand-covering(T3)and bare land(CK)were set up,using correlation analysis and membership function value method.The effects of the three surface coverings on the plants were evaluated.The T1,T2 and T3 treatments significantly increased the soil moisture content in different months(P<0.05),and the average soil moisture content increased by 26.1%,27.9%and 23.5%,respectively,and the coverage increased significantly.The growth rate of T2 was the highest in the growth rate,plant height and ground diameter.The coverage of all leaves increased the net photosynthetic rate(P n),stomatal conductance(G s)and transpiration rate(T r)(P<0.05).The value is the largest,and the T2 value is the largest in the middle and late growth stages;the maximum net photosynthetic rate(P max),the maximum light saturation point(L SP),the lowest light compensation point(L CP)and the dark respiration rate(R d)are the lowest in T2 treatment.The effects of(W UE)and apparent quantum efficiency(A QY)were small;plant growth was significantly positively correlated with soil water content,P n,G s,P max,and L SP(P<0.01),and the combined effect from strong to weak was T2.T3,T1,and CK.Therefore,it is more suitable to apply straw mat in the process of planting P.euphratica seedlings.