外源水杨酸对NaCl胁迫下棉花幼苗生长生理特性的影响

Effects of Exogenous Salicylic Acid on the Physiological Characteristics and Growth of Cotton Seedlings under NaCl Stress

以‘中棉所41号’(耐盐品种)和‘中棉所49号’(中等耐盐品种)为试验材料,采用水杨酸(SA)浸种+叶面喷施复合处理,通过温室盆栽试验探究了0.60%NaCl胁迫下外源SA对棉花幼苗生长、渗透调节能力和抗氧化能力的影响。结果表明:(1)NaCl胁迫显著抑制了棉花幼苗的生长,外源SA处理下棉花幼苗的株高、叶面积、干物质质量、根系活力、根冠比均有升高,叶片中丙二醛(MDA)、可溶性糖(SS)、可溶性蛋白(SP)和脯氨酸(Pro)含量增加,叶片和根系中超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性显著提高,且棉花幼苗根系的SOD、POD和CAT活性小于叶片,SA处理对棉花幼苗根系酶活力的提高幅度大于叶片。(2)SA浸种+叶面喷施复合处理对0.60%NaCl胁迫的缓解作用优于单独SA浸种处理,尤以0.05mmol·L^(-1)浸种+0.2mmol·L^(-1)叶面喷施处理最好。(3)两品种比较,SA对‘中棉所49号’的盐胁迫缓解作用大于‘中棉所41号’,且以棉花幼苗根系生长发育的表现最为显著;外源SA使‘中棉所41号’的根系活力提高10.58%~57.56%,‘中棉所49号’提高15.08%~80.48%。研究发现,外源SA能通过调控棉花幼苗的渗透调节和抗氧化能力来减轻细胞膜损伤,提高其耐盐性,但缓解效应在不同耐性品种和处理方式间存在明显差异。

In order to study the salicylic acid （SA） on the growth of cotton seedlings under salt stress and resistance physiology, We used ‘ Zhongmiansuo 41’ （tolerant varieties） and ‘Zhongmiansuo 49’ （medium tolerant varieties） as material. On 0.60% NaCl stress conditions, using seed soaking and spraying application method of exogenous SA cotton, we investigated the seedling growth, osmotic adjustment matter content and antioxidant system. The results showed that： （1） NaCl stress significantly inhibited the growth of cotton seedlings, under NaCl stress with SA soaking＋spraying treatment, cotton seedling height, leaf area, dry mass, root activity, root/shoot ratio were increased, and malondialdehyde （MDA）, soluble sugar （SS）, soluble protein （SP） and proline （Pro） contents were increased in leaves when exogenous SA had been applied, together with significant decrease in superoxide dismutase （SOD）, peroxidase （POD） and catalase （CAT） activities in leaves and roots. The activities of SOD, POD and CAT in roots of cotton seedlings were smaller than those of leaves, and the SA treatment increased the enzyme activities of cotton seedling roots more than that in leaves; （2） SA soaking＋spraying composite treatment on 0.60%NaCl mitigation effect is better than that of SA seed soaking treatment, while the 0.05 mmol·L^-1 soaking ＋0.2 mmol·L^-1 spraying treatment is the best; （3） Comparison of two varieties, SA on the ‘Zhongmiansuo 49’ to alleviate salt stress intensity is greater than that on the ‘Zhongmiansuo 41’, especially in cotton seedling root growth is most evident, exogenous SA could made the root activity of ‘Zhongmiansuo 41’ improved 10.58%-57.56%, ‘Zhongmiansuo 49’ improved 15.08%-80.48%. The study found that exogenous SA could alleviate cell membrane damage and increase salt tolerance by regulating osmotic adjustment and antioxidant capacity of cotton seedlings, but the effect of alleviation was different between different tolerant cultivars and treatments.