为明确氮沉降和降水增加下榆树幼苗非结构性碳水化合物(NSC)的响应规律，采用双因素随机区组设计，设置4个氮沉降水平(0、5、10和15 g N·m-2·a-1)以及3个水分水平(自然降水、自然降水增加50％和100％)，分析不同器官(叶片、枝条、主干、粗根和细根)中可溶性糖、淀粉及NSC浓度。结果表明:未施氮处理下，降水增加引起枝条、主干、粗根和细根中可溶性糖浓度降低，而叶片可溶性糖浓度保持稳定。在自然降水下，氮沉降增加导致叶片、枝条和主干中可溶性糖浓度上升，细根中可溶性糖浓度降低。氮沉降和降水增加对各器官中NSC浓度均具有显著的交互作用。施氮15 gN·m-2·a-1处理下，与自然降水相比，降水增加50％时，各器官中淀粉浓度下降;降水增加100％时，枝条、主干和粗根中可溶性糖、淀粉及NSC浓度减少。因而，氮沉降可增加榆树幼苗NSC的储存，降水增加50％有利于促进幼苗生长。
Nitrogen deposition and increased precipitation and their coupling effects on non-structural carbohydrates allocation of Ulmus pumila seedlings
To elucidate the response of non-structural carbohydrates(NSC)of Ulmus pumila seedlings to nitrogen deposition and increasing precipitation,we analyzed concentrations of soluble sugar,starch,and NSC in different organs(leaf,branch,stem,coarse root and fine root)under a full-factorial experiment,i.e.,four levels of nitro-gen deposition(0,5,10,and 15 g N·m-2·a-1)and three precipitation levels(natural precipitation,50％and 100％increase in precipitation)with randomized block design.The results showed that increased precipitation caused the decrease of soluble sugar concentrations in branches,stems,coarse roots and fine roots,but did not affect leaf soluble sugar concentration under treatment without nitrogen addition.With increasing nitrogen deposi-tion,under natural precipitation,soluble sugar concentrations increased in leaves,branches and stems but decreased in fine roots.There were pronounced interactions between nitrogen deposition and increased precipitation on NSC concentrations in each organ of U.pumila seedlings.Under 15 g N·m-2·a-1 nitrogen addition treatment,compared to natural precipitation,starch concentrations in each organ decreased under 50％increase in precipitation,while soluble sugar,starch and NSC concentrations in branches,stems and coarse roots decreased under 100％increase in precipitation.Therefore,nitrogen deposition would increase NSC storage of U.pumila seedlings,and 50％increase in precipitation is conducive to promote seedling growth.
water and nitrogen couplingcarbon allocationsoluble sugarstarchclimatic change
万方数据
维普
