盐地碱蓬养分重吸收对不同水盐交互梯度的响应

Nutrient Resorption Response to Different Water-Salt Interaction Gradients of Suaeda salsa

植物的养分重吸收是植物适应逆境的重要生态机制.利用盆栽模拟试验,设置28个水盐交互梯度,研究典型盐生植物盐地碱蓬在不同生长发育阶段N、P、K、Na四种元素的重吸收特征.结果表明:盐地碱蓬营养生长阶段和繁殖生长阶段的养分重吸收效率均低于全球陆生植物水平,且营养生长期高于繁殖生长期.N、P、K、Na元素的重吸收效率在营养生长期分别为51.90%、50.79%、28.79%、-19.58%,在繁殖生长期分别为28.60%、27.75%、13.61%、-26.67%.四种元素的重吸收响应水盐梯度的敏感性存在较大差异.在营养生长期,盐分和干旱对P的重吸收具有显著负效应,干旱对K的重吸收具有正效应;在繁殖生长期,盐分对N的重吸收具有显著负效应,对P、Na的重吸收具有正效应.在不同生长阶段,四种元素的重吸收对胁迫响应的差异,体现了植物在抵御胁迫与增加生长的综合需求下,体内元素的吸收、运移、分配策略不同.

The nutrient resorption is an important ecological mechanism for plants to adapt to adversity.In this study,a typical halophyte,Suaeda salsa,was selected for pot experiments to study the nitrogen,phosphorus,potassium and sodium resorption efficiency(NRE,PRE,KRE and NaRE)in response to salt and drought stress at different growth periods.The results showed that the nutrient resorption efficiency in vegetative period and reproductive period was lower than those of global terrestrial plants and vegetative period was higher than repro-ductive period.The resorption efficiency of nitrogen,phosphorus,potassium and sodium were 51.90%,50.79%,28.79%,-19.58%in vegetative period and 28.60%,27.75%,13.61%,-26.67%in reproductive period,respectively.The sensitivity of the element resorption efficiencies to different water-salt gradients was quite different.During vegetative period,salt and drought had a significant negative effect on PRE,while drought had a positive and neg-ative effect on KRE;during the reproductive period,salt had a significant negative effect on NRE,and a positive effect on PRE and NaRE.The differences of element resorption response to stress at two growth stages reflected the different uptake,transport and distribution strategies of the elements in plants when responding to stress and meeting nutrient requirements for growth.