外源钙对根际低氧胁迫下黄瓜植株钾、钙、镁离子含量和ATPase活性的影响

Effects of Exogenous Calcium on K^+,Ca^(2+),Mg^(2+) Content and ATPase Activity in Cucumber Seedlings Under Root-zone Hypoxic Stress

以黄瓜(Cucumis sativus L.)'新泰密刺'品种为材料,采用营养液栽培,研究了外源Ca2+对根际低氧胁迫下幼苗植株离子含量和ATPase活性的影响。结果表明,常钙低氧处理植株体内K+、Ca2+、Mg2+含量和质膜、液泡膜、内质网膜ATPase活性显著降低;营养液增施4mmol·L-1CaCl2明显缓解了低氧胁迫对植株的伤害,根中K+、Ca2+、Mg2+含量,根系质膜、液泡膜、内质网膜H+-ATPase和Ca2+-ATPase活性,显著高于常钙低氧处理,接近或达到对照水平;根际低氧胁迫下营养液增施Ca2+通道抑制剂La3+(50μmol·L-1H+)显著,降低了幼苗体内K+、Ca2+含量,但对Mg2+含量影响不显著,营养液增施La3+显著降低了质膜H+-ATPase和Ca2+-ATPase的活性,但对液泡膜,内质网膜H+-ATPase和Ca2+-ATPase活性影响不显著。外源钙通过增加黄瓜体内矿质营养离子的吸收和转运,维持质膜、液泡膜和内质网膜ATPase活性,从而缓解低氧胁迫对植株造成的伤害,增强黄瓜植株的低氧耐性。

A hydroponic experiment was carried out to explore the effects of exogenous calcium and H^＋ on ion content and ATPase activity of cucumber under hypoxic stress.The results showed that K^＋,Ca^2＋,Mg^2＋ contents were significantly lower and plasma membrane,tonoplast,endoplasmic reticulum ATPase activities were significantly decreased under hypoxic stress.Application of 4 mmol · L^-1 CaCl2 in nutrient solution significantly alleviated the hypoxic stress,and the K^＋,Ca^2＋,Mg^2＋ contents were significantly higher than those in the hypoxic treatment,while the plasma membrane,tonoplast,endoplasmic reticulum H^＋-ATPase and Ca^2＋-ATPase activities were significantly higher than hypoxic treatment and closed to the control level.Application of 50 μmol · L^-1 H^＋ in nutrient solution significantly reduced the contents of K^＋,Ca^2＋,while the content of Mg^2＋ was not significantly differed from the hypoxic treatment.H^＋-ATPase and Ca^2＋-ATPase activities of plasma membrane were significantly lower than the hypoxic treatment,but the H^＋-ATPase and Ca^2＋-ATPase activities of vacuole membrane and endoplasmic reticulum were not significantly differed from the hypoxic treatment.It is suggested that application of exogenous calcium ions can increase the mineral absorption and transport,enhanced the activities of ATPase,and alleviated the hypoxic injury of cucumber and enhanced cucumber tolerance hypoxia.