草业学报2016，Vol.25Issue(9)：54-63,10.DOI:10.11686/cyxb2016064
水分胁迫下不同氮素对多枝柽柳幼苗生长及生理的影响
Effects of different forms of nitrogen on the growth and physiology ofTamarix ramosissima seedlings under water stress
摘要
Abstract
Tamarix ramosissima is a dominant species in the lower reaches of the Tarim River,and plant sur-vival and growth is affected by a double stress of nutrient and seasonal water deficit in the sandy soils in this lo-cality.More detailed information on the stress responses of this species will assist the process of ecological res-toration in the Tarim River lower reaches.Four soil watering regimes (D1 -20%,D2 -35%,D3 -50% and D4 -75% of relative field capacity)and two forms of fertilizer N;KNO3 (N1 )and NH4 Cl (N2 )were provided in order to explore drought stress and nitrogen responses.Changes in plant growth and photosynthetic physio-logical traits were measured shortly before flowering.Key results were:1 )Water is the main limiting factor for growth of T.ramosissima seedlings,and an increase in plant height occurred with the enhancement of N supply.For D1 ,ammonium nitrogen significantly affected plant height,but nitrate nitrogen was more signifi-cant for D4 .2)When seedlings were subjected to water stress,the two forms of nitrogen affected chlorophyll content differently.At higher soil moisture content in D2 and D3 ,chlorophyll b was increased more by ammo-nium nitrogen supply than chlorophyll a.At D3 ,the nitrate nitrogen was only increased the contents of chloro-phyll a.3)With enhanced N supply,we found an increase in photosynthetic efficiency (φPS(Ⅱ)-quantum yield of PSⅡ and ETR-estimated electron transport rate).At D1 and D3 the effect of ammonium nitrogen was more sig-nificant,but at D2 the effect of nitrate was more significant.4)Ammonium nitrogen was more easily absorbed by the root to promote total biomass accumulation,and nitrate nitrogen significantly increased the total bio-mass of seedlings only in the D4 soil water regime.With enhancement of N supply,the specific root length de-creased significantly when the soil water content is D2 and D3 ,it indicated that aboveground biomass of plant occupied more assignments.Under reduced water supply,the root∶shoot ratio of nitrate nitrogen was signifi-cantly increased,and captured nitrogen appears to have been consumed by growing roots.With adequate water (D3 ),ammonium nitrogen effects root ∶shoot ratio was significantly decreased,and the N appears to have been used to increase crown diameter.Therefore,water is the key factor in management of T.ramosissima seedlings,and when seedlings absorb nitrogen,the combined effect of water and nitrogen can improve seedling photosynthesis and growth and allow the seedlings to grow successfully in these undesirable surroundings.关键词
多枝柽柳幼苗/氮素/水分/叶绿素荧光/根系Key words
Tamarix ramosissima seedlings/nitrogen/water/chlorophyll fluorescence/root引用本文复制引用
吕豪豪,马晓东,张瑞群,钟小莉,朱成刚,杨余辉..水分胁迫下不同氮素对多枝柽柳幼苗生长及生理的影响[J].草业学报,2016,25(9):54-63,10.基金项目
国家自然科学基金项目（41261103），中国科学院西部之光项目（2015-XBQN-A-09），荒漠与绿洲生态国家重点实验室开放基金，自治区自然科学基金（2012211B18）和国家科技支撑计划课题（2014BAC15B02）资助。 （）
