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。
As a second messenger, Ca^2＋ plays an important role during the plant resistance to biotic or non-biotic stress. And as a carrier of Ca^2＋ , Ca^2＋ -ATPase intervenes in many reactive processes of outer stimulation, so as to keep steady-state [ Ca^2＋ ]cytlevel. 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 resuits Showed that the Ca^2＋ -ATPase activities of normal plant changed with the longer light from 7 ： 00 AM to 7 ： 00 PM. In generally,thetotal Ca^2＋ -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 Ca^2＋ -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 Ca^2＋ -ATPase activities of three membranes were all increased by PEG in leaves, and so as to both mitochondrion membrane and vocuole membrane in root. But the Ca^2＋- ATPase of cytoplast was inhibited obviously by PEG. Four outer reagents had different effects on Ca^2＋-ATPase activity. In leaves, the decrease of Ca^2＋ -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 reversed the decrease by PEG in cytoplast membrane, and increased Ca^2＋ -ATPase activities of mitochondrion membrane, and the vacuole membrane Ca^2＋ -ATPase activity were increased by ABA obviously. Different from those, TFP could promote the Ca^2＋ -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 [Ca^2＋ ]cyt under osmotic stress. External reagents influenced Ca^2＋ -ATPase activities both leaves and roots, but the response differences existed between leaves and roots.
出处
《华北农学报》
CSCD
北大核心
2008年第4期129-134,共6页
Acta Agriculturae Boreali-Sinica
基金
河北省自然科学基金项目(2007000994200600727)
