Responses and sensitivity of N, P and mobile carbohydrates of dominant species to increased water, N and P availability in semi- arid grasslands in northern China  

作　　者：Xue Wang Zhuwen Xu Caifeng Yan Wentao Luo Ruzhen Wang Xingguo Han Yong Jiang Mai-He Li 

机构地区：[1]Key Laboratory of Forest Ecology and Management,Institute of Applied Ecology,Chinese Academy of Sciences,No.72 Wenhua Road,Shenhe District,Shenyang 110016,China [2]College of Resources and Environment,University of Chinese Academy of Sciences,No.19A Yuquan Road,Shijingshan District,Beijing 100049,China [3]Forest dynamics,Swiss Federal Research Institute WSl,Zuercherstrasse 111,CH-8903 Birmensdorf,Switzerland

出　　处：《Journal of Plant Ecology》2017年第3期486-496,共11页植物生态学报（英文版）

基　　金：The National Natural Science Foundation of China(41371076,31370009);the National Key Basic Research Program of China(2011CB403204);the State Key Laboratory of Forest and Soil Ecology(LFSE2013-01).

摘　　要：Aims We aimed to improve the understanding of the carbon and nutri-ent physiological responses and adaptation of semi-arid grassland plants to environmental changes.Methods We investigated plant leaf non-structural carbohydrate(NSC=solu-ble sugars+starch),nitrogen(N)and phosphorus(P)levels in an Inner Mongolian semi-arid grassland community treated with water,N and P additions for 8 years.Two dominant grasses(Agropyron cris-tatum(L.)Gaertn.,Stipa krylovii Roshev.)and two forbs(Artemisia frigida Willd.,Potentilla bifurca L.)were analyzed.Important Findings Water addition decreased plant leaf N and P concentrations,whereas N and P addition increased them,indicating that the semi-arid grassland studied suffers from a shortage of N and P sup-ply.Both N and P addition decreased the levels of soluble sugars,starch and thus also NSC in plant leaves,which may be attributed to(i)increased carbohydrate consumption associated with a higher growth rate,and(ii)a dilution effect of greater plant size under N and P addition.Water addition tended to increase the leaf NSC levels both in the grasses(+9.2%)and forbs(+0.6%only),which may be a result of increased photosynthesis of plants with increased water availability.Under conditions of ambient and increased water supply in the present study,N addition resulted in an N/P ratio of>16 in the grasses but a significantly lower N/P ratio of<11 in the forb species.This finding implies that growth of the two grass spe-cies will be limited mainly by P availability but the forbs will still be mainly limited by N supply if N deposition,alone or in combination with summer precipitation,continues to increase as predicted in Inner Mongolia.

关 键 词：climate change non-structural carbohydrates perennial grasses perennial forbs STEPPE 

分 类 号：S81[农业科学—畜牧学]