激素对陆地棉矮化突变体AS98的生理影响

分别用外源激素GA3、BR和IAA处理棉花极端矮化突变体AS98,比较分析突变体内源激素GA、IAA、ZR和ABA的含量、α-淀粉酶、POD和SOD活性变化,探索该矮化突变体的矮化机理。结果显示,施用外源GA3能显著增加AS98叶片GA、IAA、ZR和ABA的含量,GA的相对变化值(VR)为60.4%～64.5%,IAA的VR为6.8%～12.3%,ZR的VR为11.7%～30.7%,ABA的VR为45.7%～82.3%;低浓度外源IAA对AS98的内源GA和IAA的合成具有一定的促进作用,其VR分别为49%和0.67%,外源IAA对ZR的合成具有抑制效应,其VR为-21.5%～-30.2%,对ABA的合成具有一定的促进效应,其VR为5.1%～35.4%;外源BR对AS98的内源GA和ABA的合成具有促进作用,其VR分别为25.3%～30.4%和3.0%～65.6%,对ZR的合成具有抑制作用,其VR为-32.1%～-40.9%,而对IAA的合成具有明显的浓度效应,低浓度促进IAA合成,高浓度抑制IAA合成。外源GA3对AS98的α-淀粉酶活性影响具有浓度效应,低浓度具有促进作用,0.3μmol/L的GA3使α-淀粉酶活性提高82%。PP333对α-淀粉酶活性具有抑制作用,1.2μmol/L的PP333使α-淀粉酶活性降低42%,而且PP333对α-淀粉酶活性的抑制作用可以通过施用GA3得到恢复。PP333对SOD活性有促进作用,1.5μmol/LPP333SOD活性提高35%,而GA3对SOD活性具有抑制作用,1.5μmol/L使SOD活性降低48%。结果表明,AS98是一个GA缺陷型矮化突变体,施用外源GA3能使促进和抑制生长的内源激素显著增加,同时,使α-淀粉酶活性增加,POD和SOD活性降低,而PP333对α-淀粉酶活性的抑制作用可以通过施用GA3得到恢复。

PHYSIOLOGY EFFECTS OF EXOGENOUS HORMONES ON A COTTON DWARF MUTANT AS98 (gossypium hirsutium L.)

AS98,a novel super-dwarf mutant of cotton (gossypium hirsutium L.),was used to study the dwarfmechanism.AS98 treated by different exogenous hormones of GA3,BR and IAA at budding stage,and the changes of endogenous hormones GA,IAA,ZR and ABA,and activities of α-amylase,POD and SOD in leaves were investigated.The contents of endogenous GA,IAA,ZR and ABA measured by ELISA method.The activities of α-amylase,POD and SOD were investigated by 3,5-dinitrosalicylic acid method,guaiacol method and nitroblue tetrazolium (NBT) method,respectively.The results indicated that the contents of endogenous GA,IAA,ZR and ABA were increased in the leaves of AS98 after treated with exogenous GA3(0.15μmol/L).The variance rates (VR) of GA,IAA,ZR and ABA were 60.4%～64.5% ,6.8%～12.3% ,11.7%～30.7% and 45.7%～82.3% ,respectively.The biosynthesis of GA and IAA were promoted 49% and 0.67% by the lower concentration of exogenous IAA.After spraying exogenous IAA,the content of endogenous ABA was increased by 5.1%～35.4%,hut the content of ZR was decreased 21.5%～30.2%.Exogenous BR promoted endogenous GA and ABA synthesis,and reduced endogenous ZR content,but the influence on the content of endogenous IAA had obvious concentration effect.The VRs of GA,ABA and ZR were 25.3%～30.4% ,3.0%～65.6% and-32.1%～-40.9% ,respectively.The content of endogenous IAA was increased by application of lower concentration exogenous BR and decreased by application high concentration BR.The α-amylase activity was up-regulated 82% by the lower concentration exogenous GA3 (0.15μmoL/L).On the contrary,the α-amylase activity was reduced 42% by application exogenous PP333 (1.2μmol/L),and the effect could be rescued by application exogenous GA3.The SOD activity were increased 35% by application PP333(0.15μmol/L) ,but it was inhibited 48% by application GA3(0.15μmol/L).Those results showed that AS98 was a GA deficient dwarf mutant.The application of the exogenous GA3 could significantly increase endogenous hormones both promoting and inhibiting plant growth,upregulate the α-amylase activity and decrease the POD and SOD activities.Moreover,the inhibition effect of α-amylase activity by application exogenous PP333 could he relieved by application exogenous GA3.