NaHCO_3胁迫下新疆枸杞和枸杞的渗透调节作用

Osmotic Adjustments in Lycium dasystemum and Lycium chinense Under NaHCO_3 Stress

试验采用不同浓度的NaHCO_3溶液对新疆枸杞和枸杞幼苗进行碱胁迫处理,分析碱胁迫对新疆枸杞和枸杞幼苗的生长、无机离子和有机溶质质量摩尔浓度及其渗透调节贡献率的影响,研究两种枸杞对碱胁迫的生理适应机制。结果表明:轻度胁迫促进了两种枸杞的生长,随胁迫强度的增加两种枸杞生长受到抑制。NaHCO_3胁迫下两种枸杞均表现出有效的渗透调节机制,Na^+对新疆枸杞和枸杞根渗透调节的相对贡献最大,平均贡献率分别为17.44%和11.66%;有机酸对渗透调节的贡献仅次于Na^+,平均贡献率分别为10.72%和9.97%;可溶性糖也在新疆枸杞和枸杞根部渗透调节中发挥了一定作用,轻中度胁迫下葡萄糖对新疆枸杞根渗透调节贡献最大,重度胁迫下蔗糖贡献最大。各盐分,蔗糖对枸杞根渗透调节贡献最大。在对照和轻中度胁迫处理下,脯氨酸对新疆枸杞和枸杞根渗透调节的贡献可忽略不计,但在重度胁迫下脯氨酸的贡献率显著提高,且脯氨酸在新疆枸杞根部渗透调节中的作用更为明显。新疆枸杞对抗NaHCO_3胁迫的能力强于枸杞,新疆枸杞对NaHCO_3胁迫较强的抗性与其更高的Na^+、脯氨酸、有机酸等渗透调节剂的积累效率及这些渗透调节剂在渗透调节中的更为突出贡献有关。

An experiment was conducted to study the effects of alkali stresses on the growth,the concentrations and contributionsof inorganic ions and organic solutes of Lycium dasystemum and L. chinense seedlings treated with different concentrations ofNaHCO3 focusing on its physiological adaptive mechanisms against alkali stresses. The growth of two Lycium species wasimproved under lower stress intensity compared with that of control,and then they displayed significant growth reductionwith the increase of NaHCO3 concentration in the culture media. Two Lycium species displayed effective osmotic adjustment mechanisms. Na＋was the major contributor in two Lycium species roots with the average contributions of 17.44%and 11.66%,respectively. Organic acids were the second important contributors with the average contributions of 10.72%and 9.97%,respectively. Soluble sugars also played a certain role in the osmotic adjustment of two Lycium species roots.Glucose was the most important contributor in L. dasystemum roots under low and moderate salinity,and it was sucrose under severe salt stress. Regardless of the salt treatment,the role of sucrose in the osmotic adjustment of L. chinense roots wasthe most important. Except severe stress,the role of proline in the osmotic adjustment of two Lycium species roots was negligible. L. dasystemum exhibited greater NaHCO3 tolerance than that of L. chinense,and it was related to the higher accumulation efficiency of Na＋,proline,and organic acids,and the more prominent contributions of these osmolytes in the osmotic adjustment.