等渗Ca(NO3)2和NaCl胁迫对黄瓜幼苗生长及渗透调节物质含量的影响

采用营养液培养方法,以耐盐性较弱的‘津春2号’黄瓜品种为试材,研究了等渗Ca(NO3)2和NaCl胁迫对黄瓜幼苗生长、根系电解质渗透率、根系活力、Na+和K+含量及渗透调节物质含量的影响。结果显示:(1)在84mmol.L-1 NaCl和56mmol.L-1 Ca(NO3)2等渗胁迫下,黄瓜幼苗鲜重和干重均显著下降,且NaCl处理下降的幅度大于等渗Ca(NO3)2处理。(2)NaCl主要通过对黄瓜根系的伤害来抑制植株生长,表现为根系活力下降、根系质膜透性增大、Na+大量积累、K+含量显著下降、Na+/K+明显上升,最终导致根冠比下降;而Ca(NO3)2处理对根系质膜透性、K+含量、Na+/K+的影响均小于NaCl胁迫,且根系活力和根冠比上升,但Ca(NO3)2胁迫后叶片含水量和渗透调节能力均小于NaCl胁迫。(3)NaCl胁迫条件下,黄瓜幼苗内渗透调节物质以可溶性糖为主,而Ca(NO3)2胁迫以可溶性蛋白为主。研究表明,NaCl胁迫对黄瓜幼苗的伤害大于等渗Ca(NO3)2,NaCl主要通过破坏根系质膜结构影响植株生长,而Ca(NO3)2主要通过引起地上部生理干旱来影响植株生长。

Effects of Iso-osmotic Ca(NO3)2 and NaCl Stress on the Growth and Osmotic Substances of Cucumber Seedlings

The experiment was carried out to study the effects of iso-osmotic Ca(NO3)2 and NaCl stress on the growth and osmotic substances of cucumber ’Jinchun No.2’(with less salt resistance) seedlings in hydroponics.The results showed that:(1)The fresh and dry biomass weight were significantly decreased under both salt stress,but the decreased degree that under NaCl stress exceeded under Ca(NO3)2 stress.The root activity,K+ content in root,K+/Na+ ratio,root-shoot ratio were significantly decreased,but the root relative membrane permeability increased significantly under 84 mmol·L-1 NaCl stress.(2)NaCl stress inhibited seedlings growth mainly by restraining root growth;However,the effects of Ca(NO3)2 stress on the root relative membrane permeability,K+ content,and the ratio of K+/Na+ were less than that under NaCl stress.The root activity and root-shoot ratio were significantly increased under Ca(NO3)2 stress,but the leaf water content and osmotic adjustment was less than that under NaCl stress.(3)Soluble sugar is the main osmotic adjustment substance under NaCl stress,but mainly soluble protein under Ca(NO3)2 stress.The results showed that both treatments caused damage to cucumber seedlings plant,and iso-osmotic NaCl stress brought about heavier damage than that of Ca(NO3)2 stress.Ca(NO3)2 stress inhibited growth mainly by inducing physiological drought and NaCl mainly by destroying root plasma membrane structure.