外源Ca2+调控野生抚育独一味幼株抗寒生理特性的研究

A study of exogenously applied Ca2+ to control physiological characteristics of cold tolerance for wild fostered Lamiophlomis rotata seedlings

独一味是青藏高原区濒危保护药用植物,幼株抗寒性较差,为揭示外源Ca^2+对调控野生抚育独一味幼株抗寒效应,对甘肃玛曲县野生抚育的独一味幼株带土坨全株移植培养盆,采用不同浓度CaCl2溶液(0,5,10,15,20和25 mmol·L^-1)喷施,以喷蒸馏水为对照,然后将培养盆分别置于4,0和-4℃处理24 h,对照留置25℃,处理结束测定叶片膜稳态性、渗透调节机能、膜质过氧化和抗氧化酶活性以及根系三苯基氯化四氮唑还原活力等抗逆指标,旨在探寻提高野生独一味幼株抗寒性的栽培生理调控方法,为独一味野生抚育和驯化栽培提供科学依据。结果表明,外源钙对低温处理后独一味抗逆指标具有显著影响,影响程度因处理浓度的不同而异,以喷施15 mmol·L^-1 CaCl2的作用效果最佳,可通过调控叶片可溶性糖和抗氧化酶活性保护膜系统的稳态性和完整性,使叶片相对电导率和丙二醛含量维持在较低的水平,增强了根系活力,有效提高了野生独一味幼株的抗寒性,在独一味野生抚育中具有潜在的应用价值。

Lamiophlomis rotata is an endangered medicinal plant found in the Qinghai-Tibet Plateau.The seedlings of L.rotata have poor cold resistance.In order to better understand the physiology of cold injury in this species and to provide scientific information that may lead to more successful domestic cultivation,the effect of exogenously applied Ca2+on cold resistance regulation of wild seedling plants was investigated.Seedlings with soil(from Maqu County,Gansu Province)were transplanted into pots.Different concentrations of CaCl2 solution(0,5,10,15,20 and 25 mmol·L^-1)were sprayed onto the seedlings,and the seedlings then immediately exposed to a range of low temperatures(4,0 and-4℃)for 24 h,while pots of a control(CK)treatment were maintained at 25℃.After the 24 h cold exposure,various physiological traits including membrane stability,osmotic adjustment,membrane lipid peroxidation,and antioxidant enzyme activities in the leaves of the seedlings were measured.The results showed that exogenous Ca^2+had a significant impact on the resistance index of L.rotata after low temperature treatment,and the magnitude of the protective effect varied across the tested concentrations.The optimal CaCl2 application rate was 15 mmol·L^-1.At this CaCl2 concentration,the test plants had significantly increased soluble sugar content,and increased activities of antioxidant enzymes such as superoxide dismutase and peroxidase,which consequently reduced the membrane lipid peroxidation and enhanced the stability of the membrane systems.In addition,exogenous Ca2+reduced relative membrane conductivity and leaf malondialdehyde content and increased root activity.In conclusion,exogenous Ca^2+improved the cold resistance of L.rotata seedlings,and has potential value as a tool to enhance cold tolerance in domestication and culture of L.rotata.