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草业学报 ›› 2016, Vol. 25 ›› Issue (9): 54-63.DOI: 10.11686/cyxb2016064

• 研究论文 • 上一篇    下一篇

水分胁迫下不同氮素对多枝柽柳幼苗生长及生理的影响

吕豪豪1, 马晓东1,2*, 张瑞群1, 钟小莉1, 朱成刚2, 杨余辉1   

  1. 1.新疆师范大学生命科学学院,新疆特殊环境物种多样性应用与调控自治区重点实验室,新疆 乌鲁木齐 830054;
    2.新疆荒漠与绿洲生态国家重点实验室,新疆 乌鲁木齐 830011
  • 收稿日期:2016-03-02 出版日期:2016-09-20 发布日期:2016-09-20
  • 通讯作者: E-mail: mxd1107@126.com
  • 作者简介:吕豪豪(1991-),女,新疆玛纳斯人,在读硕士。E-mail:lh910415@163.com
  • 基金资助:
    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

Effects of different forms of nitrogen on the growth and physiology of Tamarix ramosissima seedlings under water stress

LV Hao-Hao1, MA Xiao-Dong1,2,*, ZHANG Rui-Qun1, ZHONG Xiao-Li1, ZHU Cheng-Gang2, YANG Yu-Hui1   

  1. 1.College of Life Science, Xinjiang Normal University, Xinjiang Special Environmental Diversity Control and Application Key Laboratory of the Autonomous Region, Urumqi 830054, China;
    2.State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Urumqi 830011, China
  • Received:2016-03-02 Online:2016-09-20 Published:2016-09-20

摘要: 多枝柽柳是塔里木河下游优势物种,下游生态恢复过程中多枝柽柳幼苗的成活及其生长受水分和养分双重胁迫。本试验设置4个水分梯度(土壤相对含水量分别为D1-20%、D2-35%、D3-50%与D4-75%)并选用两种氮素(N1-KNO3与N2-NH4Cl)来探究水分与氮素对多枝柽柳幼苗生长及生理的影响。实验结果表明,1)水分是影响多枝柽柳幼苗表观生长的主要因子,施氮对其株高有显著的促进作用,D1时铵态氮对其株高的促进作用显著,而D4时硝态氮的促进作用更为显著。2)幼苗在D1受到严重胁迫时,两种氮素对叶绿素a的含量均有显著的促进作用,铵态氮在土壤水分为D2、D3时,对叶绿素b有显著的促进作用。3)施氮可以提高幼苗的光合效率(φPS(Ⅱ)和ETR),D1、D3时,铵态氮对其影响显著,D2时硝态氮对其影响显著。4)铵态氮更容易被幼苗根系吸收用于总生物量的积累,硝态氮只有在水分D4时对其总生物量有显著的促进作用,土壤水分为D2、D3时,施氮使其比根长显著减小,说明幼苗生物量的分配更趋向地上部分;当水分不足时,硝态氮显著增加其根冠比,氮素更多地被幼苗用于根系生长,只有水分适宜时(D3),铵态氮使其根冠比显著减小,用于地上冠面积的增长。因此,水分作为多枝柽柳幼苗早期生长的关键因子,幼苗吸收氮素后与其之间的耦合效应,有利于幼苗改变表观生长及光合生理来适应不良的环境。

Abstract: Tamarix ramosissima is a dominant species in the lower reaches of the Tarim River, and plant survival and growth is affected by a double stress of nutrient and seasonal water deficit in the sandy soils in this locality. More detailed information on the stress responses of this species will assist the process of ecological restoration 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 NH4Cl (N2) were provided in order to explore drought stress and nitrogen responses. Changes in plant growth and photosynthetic physiological 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 significant 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 ammonium nitrogen supply than chlorophyll a. At D3, the nitrate nitrogen was only increased the contents of chlorophyll 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 significant, 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 biomass of seedlings only in the D4 soil water regime. With enhancement of N supply, the specific root length decreased 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 significantly 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.