Effect Of Ca～(2+)on The Heat Tolerance Of Peanut Seedlings And Study Of The Mechanism

After being prelreaied with external Ca2 + (lOmmol/L), peanut seedlings were stressed at 42℃ .We probed into the mechanism of Ca2~ effect on plants under stess such as high temperature by the measures of physiology .biochemistry and cytochemistry. The determination of heat tolerance showed that Ca2 + could inhibit effectively chlorophyll disrupted, photosynthesis rate decreased, cell membrane permeability increased and soluble protein decreased under high temperature and improve relatively the contents of proline and soluble sugar, reduced the harm of structure(so it was proved by ultramicrostructure of peanut seedlings). Its showed pretreatment with external Ca2 could improve the heat tolerance of peanut seedlings. The determination of the activity of antioxidant enzymes and non-enzyme ant ioxidative substances showed that peanut seedlings was keep at a high level after being treated with external Ca2*; SDS-PAGE of the soluble protein showed that high temperature could induce the expression of heashock protein and pretreated with external Ca2 could make these polypcptide express strengthenly .it indexed that external C a: could induce the expression of heats hock protein strengthen! y. the results of the experiment of cytochemistry showed that harm degree of ultramicrostructure of peanut seedlings pretreated with external Ca2 + was gentle than that of control, the structure of membrance system and cell wall was keeped stability relatively; the activity of Ca2*,Mg2 + -ATPase was improved and protected by Ca24 and the former was ever more obvious.