摘要： 以钙离子鳌合剂EGTA、钙通道阻断剂Vp、钙调素拮抗剂TFP和ABA分别处理玉米幼苗,对渗透胁迫下根系和叶片质膜、液泡膜、线粒体膜以及总微膜Ca²⁺-ATPase活性进行了测定。结果表明,正常条件下,叶片和根系微膜系统总Ca²⁺-ATPase活性随光照时间延长出现一个峰值。总体比较,渗透胁迫下三种膜上Ca²⁺-ATPase活性相当,而且均随渗透胁迫发生不同程度的变化。就微膜系统总酶活变化而言,叶片高于根系,渗透胁迫降低叶片酶活;而渗透胁迫对根系酶活性影响不大。分解到三种膜上,渗透胁迫对叶片酶活的提高均表现为正效应,根系上,对线粒体膜和液泡膜酶活提高表现为正效应,而对质膜酶活表现为显著抑制。外源试剂处理发现,ABA和EGTA在叶片上均可逆转PEG降低总酶活的效应,且在处理6 h时使得酶活性显著超过正常水平;而根系上表现不一:其中,Vp对质膜上PEG提高酶活效应抑制作用较大,且显著提高线粒体膜酶活;ABA显著提高液泡膜上酶活性;TFP处理在胁迫前期基本表现为促进作用,而6 h之后大都表现为抑制效应。说明:渗透胁迫下,玉米叶片质膜、液泡膜以及线粒体膜均参与了胞质钙离子稳态的调控过程,外源试剂处理对Ca²⁺-ATPase具不同程度的调节作用,叶片和根系Ca²⁺-ATPase对外源试剂响应存在差异性。

关键词: 渗透胁迫, 玉米, 微粒体膜, ²⁺-ATPase

Abstract: As a second messenger, Ca²⁺ plays an important role during the plant resistance to biotic or non -biotic stress.And as a carrier of Ca²⁺, Ca²⁺ -ATPase intervenes in many reactive processes of outer stimulation, so as to keep steady -state [ Ca²⁺] cyt level. In the report, Ca ²⁺ -ATPase activities of microsomal membrane system, including cytoplast membrane, mitochondrion membrane and vacuole membrane,were measured under osmotic stress with PEG6000.The re - sults showed that the Ca²⁺ -ATPase activities of normal plant changed with the longer light from 7: 00 AM to 7: 00 PM?In generally, the total Ca²⁺ -ATPase activities of three membranes were close and changed while plant subjected to osmotic stress, and it's higher in leaves than that in roots both treatment and control. In leaves, the Ca²⁺ -ATPase activities were decreased while treated with PEG, ABA and EGTA could reverse the effect, but it changed little in root while subjected to PEG,and were all increased by outer reagents.In detail, the Ca²⁺ -ATPase activities of three membranes were all in - creased by PEG in leaves, and so as to both mitochondrion membrane and vocuole membrane in root. But the Ca²⁺ - ATPase of cytoplast was inhibited obviously by PEG. Four outer reagents had different effects on Ca²⁺ -ATPase activity.In leaves, the decrease of Ca²⁺ -ATPase by PEG could be reversed by both ABA and EGTA, and the activities were higher than that of control at 6 h after treatment by PEG by two reagents?But the effects were different in roots.Vp could re - versed the decrease by PEG in cytoplast membrane, and increased Ca²⁺ -ATPase activities of mitochondrion membrane, and the vacuole membrane Ca²⁺ -ATPase activity were increased by ABA obviously.Different from those,TFP could pro - mote the Ca²⁺ -ATPase activity to raise in prophase of osmotic stress, but inhibited it after 6 h while treatment with PEG. Those indicated that three membrane both leaves and roots were all participate in the regulating process of keeping low [Ca²⁺ ] cyt under osmotic stress.External reagents influenced Ca²⁺ -ATPase activities both leaves and roots, but the re -sponse differences existed between leaves and roots.

Key words: Osmotic stress, Maize, Microsomal membranes, ²⁺-ATPase

中图分类号: 

• S513.01