钙离子对干旱胁迫下铁皮石斛愈伤组织保护酶系统的影响

Effects of Calcium Ion on the Protective Enzyme System of Dendrobium officinale Kirnura Callus under Drought Stress

采用铁皮石斛愈伤组织为材料,利用PEG6000模拟干旱胁迫,同时施以CaCl2或Ca(NO3)2两种外源钙处理,通过测定四种过氧化物酶系SOD、POD、ASP、CAT酶活性变化情况,研究铁皮石斛抗旱机制以及Ca2+对铁皮石斛抗旱性的影响,结果显示在干旱胁迫下,铁皮石斛体内会发生一系列生理响应机制,其中在过氧化物酶类中SOD、POD、ASP与干旱胁迫密切相关,可以作为考察铁皮石斛抗旱性的指标。通过适当钙处理,这三类酶的活性迅速提高或维持在较稳定的状态,并以此来消除干旱胁迫产生的危害。而CAT在中低程度干旱胁迫中变化不大,在重度干旱胁迫下活力下降较大,且钙处理对其影响不大。因此,本研究对于铁皮石斛愈伤组织在生长过程中减少活性氧积累以及维持膜结构的完整具有实际意义,也对铁皮石斛在组织培养、快速繁殖及抗逆栽培方面提供理论指导。

Using Dendrobium officinale ca llus as material,PEG6000 was used to simulate drought stress,two kinds exogenous calcium treatment,CaCl2 or Ca(NO3)2,were used to determine the activity of SOD,POD,ASP,and CAT enzymes in four peroxidase systems,so as to analyze the drought resistance mechanism of Dendrobium officinale and the effects of Ca2+on the drought resistance of Dendrobium officinale.The results obtained were as follows:under drought stress,a series of physiological response mechanisms occurred in Dendrobium candidum in vivo,in which SOD,POD,ASP were found to be closely related to drought stress,and these could be used as indicators of drought resistance of Dendrobium candidum.Through proper calcium treatment,the activity of these three enzymes could be rapidly increased or maintained in a more stable state,thereby eliminating the harm caused by drought stress.However,CAT did not change much in low-to-medium drought stress,but decreased greatly under severe drought stress,and calcium treatment had little effect on it.Therefore,this study would have practical significance for reducing the accumulation of active oxygen and maintaining the integrity of the membrane structure during the growth process of Dendrobium candidum callus tissue,and also might provide theoretical guidance for Dendrobium candidum in tissue culture,rapid propagation and stress resistance.