低温胁迫高山杜鹃对外源氯化钙和脱落酸的响应

Response of Exogenous Calcium Chloride and Abscisic Acid to Rhododendron alpine Under Low Temperature Stress

【目的】探明在低温(0℃)胁迫下喷施外源氯化钙(CaCl_(2))和脱落酸(ABA)对高山杜鹃幼苗生理特性的影响,为其低温栽培和抗性育种提供参考。【方法】以秦岭高山杜鹃幼苗为材料,采用单因素试验研究低温(0℃)胁迫下喷施不同浓度CaCl_(2)(600 mg/L、800 mg/L、1 000 mg/L和1 200 mg/L)和ABA(5 mg/L、10 mg/L、15 mg/L和20 mg/L)后高山杜鹃幼苗受冷害程度和株高、超氧化物歧化酶(SOD)、过氧化物酶(POD)、相对电导率、丙二醛(MDA)和可溶性蛋白含量等生理指标的变化。【结果】喷施10 mg/L ABA和800 mg/L CaCl_(2)均能有效提高高山杜鹃幼苗的抗寒性,减轻低温胁迫对其生长的抑制作用,其中,喷施10 mg/LABA缓解冷害(1~2级)的效果优于800 mg/L CaCl_(2)(2~3级)。随ABA和CaCl_(2)喷施浓度增加低温胁迫高山杜鹃的SOD和POD活性呈先升后降趋势,且均在第4天时达最高,SOD活性分别为52.97 U/g和49.82 U/g,POD活性分别为37.95 U/g和35.12 U/g;相较于低温胁迫喷施蒸馏水(对照),喷施ABA和CaCl_(2)的POD活性分别升高35.10%和25.03%,SOD活性升高21.60%和14.37%,可溶性蛋白含量达最高值时提升20.97%和7.79%,相对电导率达最高值时降低10.20%和16.65%,丙二醛达最高值时降低26.26%和33.52%。【结论】喷施10 mg/L ABA和800 mg/L CaCl_(2)能明显缓解低温胁迫对高山杜鹃造成的冷害。

【Objective】The effect of spraying exogenous calcium chloride(CaCl_(2)) and abscisic acid(ABA) on the physiological characteristics of Rhododendron alpine seedlings under low temperature(0℃) stress is investigated to provide reference for its low temperature cultivation and resistance breeding.【Method】Using Qinling R.alpine seedlings as materials,a single factor experiment is used to study the changes of the degree of chilling damage,plant height,superoxide dismutase(SOD),peroxidase(POD),relative conductivity,malondialdehyde(MDA) and soluble protein content by applying different concentrations of CaCl_(2)( 600 mg/L,800 mg/L,1 000 mg/L and 1 200 mg/L) and ABA( 5 mg/L,10 mg/L,15 mg/L and 20 mg/L) under low temperature stress.【Result】Spraying 10 mg/L ABA and 800 mg/L CaCl_(2) could effectively improve the cold resistance of R.alpine seedlings and alleviate the growth inhibition effect of low temperature stress.Among them,spraying 10 mg/L ABA had better effect of alleviating the degree of chilling damage( grade 1~2) than that of 800 mg/L CaCl_(2) to chilling damage(grade 2~3).After spraying ABA and CaCl_(2),the SOD and POD activities of R.alpine rose first and then decreased under low temperature stress,and the activities reached the highest on the 4^(th) day,the SOD activities were 52.97 U/g and 49.82 U/g,and POD activities were 37.95 U/g and 35.12 U/g,respectively.Compared with the application of distilled water(CK) under low temperature,the POD activities after spraying ABA and CaCl_(2) increased by 35.10% and 25.03%,respectively,SOD activity increased by 21.60% and 14.37% respectively,soluble protein increased by 20.97% and 7.79% when it reached the highest value,and relative conductivity decreased by 10.20% and 16.65% when it reached the highest value.When the MDA reached the highest value,it decreased by 26.26% and 33.52%.【Conclusion】Spraying 10 mg/L ABA and 800 mg/L CaCl_(2) can obviously alleviate the chilling injury caused by low temperature on R.alpine.