外源钙和赤霉素对干旱胁迫下苜蓿幼苗生理特性的影响

Effects of calcium(CaCl_2),GA_3 and complex liquid on the physiological characteristics of alfalfa seedlings under drought stress

以紫花苜蓿幼苗为材料,采用营养钵沙培1/2Hoagland营养液法,研究PEG-6000模拟干旱胁迫下不同浓度CaCl2(0,5,10,20mmol/L)、GA3(0,50,100,150 mg/L)及不同比例复合液[CaCl2∶GA3设体积比1∶1(T1∶1)、1∶2(T1∶2)、2∶1(T2∶1)及质量比1∶1(Z1∶1)]处理对苜蓿幼苗生理效应的影响,并用隶属函数法进行综合评价,探讨外源钙(CaCl2)、赤霉素(GA3)及其复合液对干旱胁迫下苜蓿幼苗缓解的生理效应及其适宜浓度、适宜复合液比例。结果表明,1)干旱胁迫下,苜蓿幼苗叶片叶绿素相对含量降低,而相对电导率、MDA含量、Pro含量、SOD活性以及POD活性均显著增加。2)与干旱胁迫下相比,经适宜浓度的CaCl2、GA3及复合液处理后,可缓解幼苗叶绿素的降解,可降低相对电导率,减少MDA的积累,保持较高的SOD、POD活性。3)利用隶属函数法得出:CaCl2处理以10mmol/L效果最好;GA3处理以100mg/L效果最好;CaCl2+GA3复合液处理以T1∶1最好,且优于单独的10mmol/L CaCl2、100mg/L GA3处理。各个处理对苜蓿幼苗干旱胁迫下的缓解效应由强到弱依次为:T1∶1>10mmol/L CaCl2>T2∶1>CK1>T1∶2>100mg/L GA3>Z1∶1>CK2。

This study aimed to investigate the effects of calcium （CaCl2 ）and GA3 on alfalfa seedlings’physio-logical characteristics under drought stress and to discover appropriate concentrations for alleviating plant damage.Alfalfa seedlings were cultured in sand.The tested concentrations for CaCl2 were 0,5,10 and 20 mmol/L;for GA3 they were 0,50,100 and 150 mg/L,also tested was a complex liquid of 10 mmol/L CaCl2 with 100 mg/L GA3 （CaCl2 ：GA3 ）.These four treatments （T1 ∶1 ,T1 ∶2 ,T2 ∶1 and Z1 ∶1 respectively）were inves-tigated under conditions of PEG-6000 drought stress.Results indicated that chlorophyll relative content de-creased under stress,while relative electrolytic leakage and MDA,Pro,SOD and POD contents increased significantly.Appropriate concentrations of CaCl2 ,GA3 and complex liquid could alleviate the degradation of seedling chlorophyll and reduce the relative conductivity and accumulation of MDA that protect film stability and reduce the content of osmotic regulation substances.They can also maintain higher SOD and POD activity and significantly improve alfalfa seedling resistance to drought stress.Using the method of subordinate function,it was found that 10 mmol/L CaCl2 ,100 mg/L GA3 and CaCl2 ＋GA3 T1 ∶1 performed better than 10 mmol/L CaCl2 and 100 mg/L GA3 .The study concluded that the relative drought relief effect of the treatments from strong to weak was T1 ∶1 〉10 mmol/L CaCl2 〉T2 ∶1 〉CK1 〉T1 ∶2 〉100 mg/L GA3 〉Z1 ∶1 〉CK2 .