外源钙对根际低氧胁迫下黄瓜幼苗ADH、LDH活性和同工酶的影响

Effects of exogenous calcium on the abundance and activity of ADH and LDH isoenzymes in cucumber seedlings root under root-zone hypoxia stress

以‘新泰密刺’黄瓜为材料,采用营养液栽培,外源使用Ca2+、钙离子通道抑制剂La3+与钙调素拮抗剂三氟拉嗪(TFP),研究了钙对根际低氧胁迫下黄瓜幼苗根系ADH、LDH活性和同工酶的影响。结果表明,低氧胁迫诱导产生了新的ADH和LDH同工酶条带。低氧胁迫下,ADH、LDH同工酶丰度和活性显著高于对照;外源增施Ca2+有利于Ca2+信号的形成和逆境信号的传递,营养液添加CaCl2缓解了低氧胁迫对黄瓜植株的伤害,ADH、LDH同工酶丰度和活性接近对照水平;La3+抑制Ca2+的吸收和体内运输,营养液添加LaCl3显著抑制了ADH和LDH同工酶丰度和酶活性,黄瓜幼苗植株生长受到抑制,生物量显著低于低氧处理,表明La3+加重了低氧胁迫对黄瓜幼苗植株的伤害;TFP抑制了低氧逆境胁迫信号的传递,营养液添加TFP抑制了ADH和LDH同工酶丰度和酶活性,ADH和LDH同工酶丰度和酶活性显著低于低氧处理,黄瓜幼苗植株生长受到抑制,黄瓜植株的低氧耐性降低。暗示外源Ca2+参与了低氧胁迫下黄瓜根系无氧呼吸代谢的调节,增强了Ca2+向植物体内的运输,缓解了低氧胁迫对黄瓜幼苗植株的伤害,增强了植物对低氧的耐性。

A hydroponic experiment was conducted to study the effects of exogenous calcium,LaCl3,and trifluoperazine （TFP） on the abundance and activity of alcohol dehydrogenase （ADH） and lactate dehydrogenase （LDH） isoenzymes in cucumber seedlings under hypoxia stress.Hypoxia induced the formation of new ADH and LDH isoenzyme bands.Under hypoxia stress,the abundance and activity of ADH and LDH isoenzymes were significantly higher than those of the control.Increasing exogenous Ca2＋ concentration was conducive to the Ca2＋ signal formation and the adversity signal transduction.The application of 4 mmol CaCl2·L-1 alleviated the hypoxia stress significantly,and made the abundance and activity of ADH and LDH isoenzymes closed to the control level.La3＋ inhibited the Ca2＋ uptake and its in vivo transport.Applying 50 μmol·L-1 of LaCl3 decreased the abundance and activity of ADH and LDH isoenzymes significantly,inhibited the growth of cucumber seedlings,and made the plant biomass be significantly lower than that under hypoxia,implying that La3＋ increased the hypoxia injury of cucumber seedlings.TFP inhibited the hypoxia signal transduction.Applying 20 μmol·L-1 of TFP made the abundance and activity of ADH and LDH isoenzymes be significantly lower than those under hypoxia,inhibited the growth of cucumber seedlings,and decreased the hypoxia tolerance of the seedlings,which implied that TFP also increased the hypoxia injury of cucumber seedlings.Our results suggested that exogenous Ca2＋ could regulate the anaerobic respiration process of cucumber roots under hypoxia stress.The exogenous Ca2＋ increased the in vivo transport of Ca2＋,alleviated the hypoxia injury,and enhanced the plant tolerance against hypoxia stress.