SA浸种对盐胁迫下小麦种子萌发和幼苗生长的影响

摘要

以小麦盐敏感品种鲁麦15为材料,研究了外源水杨酸(salicylic acid,SA)浸种对100 mmol/L NaC1胁迫下小麦种子萌发和幼苗生长的影响.研究结果表明:盐胁迫下,无论经SA浸种还是未经SA浸种,小麦幼苗的生长均受到明显抑制,干、鲜重显著下降;0.1 mmol/L、0.2 mmol/L和0.3 mmol/L SA溶液浸种均能显著缓解NaC1胁迫对小麦幼苗生长的抑制,其中以0.2 mmol/L SA溶液浸种预处理效果最好.实验中,0.2 mmol/L SA浸种可显著提高盐胁迫下小麦种子β-淀粉酶的活性和吸胀速率.此外,与未经SA浸种的盐胁迫小麦幼苗相比,0.2 mmol/L SA浸种的盐胁迫小麦幼苗整株的干、鲜重显著增加,幼苗体内Na+含量降低,K+含量和K+/Na+比值显著提高;同时,小麦幼苗叶片中超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)、过氧化物酶(peroxidase,POD)活性升高,而丙二醛(MDA)含量则显著降低.由此可以得出,SA浸种能有效提高盐胁迫下小麦幼苗体内K+/Na+比值,提高SOD、CAT和POD的活性,减轻膜脂过氧化程度,以缓解盐胁迫对小麦幼苗生长的抑制作用,从而提高耐盐性.%Seeds of Triticum aestivum L.(LM 15),a salt-sensitive wheat cultivar,were pre-soaked with salicylic acid (SA) to examine the effect of SA pretreatment on the germination and seedlings growth under 100 mmol/L NaCl.The results showed that,whether the seeds were pre-soaked with SA or not,the growth of wheat seedlings was significantly inhibited under salt stress and the seedling fresh weight (FW) or dry weight (DW) was dropped notably.However,0.1 mmol/L,0.2 mmol/L and 0.3 mmol/L SA pre-soaking significantly alleviated the growth inhibition of wheat seedlings under NaCl stress,and 0.2 mmol/L SA pre-soaking gave rise to the best alleviative effect.In the experiment,0.2 mmol/L SA pre-soaking significantly alleviated theβ-amylase activity and imbibition rate of wheat seeds under salt stress.In addition,wheat seedlings that seeds were pre-soaked with 0.2 mmol/L SA had more FW and DW,lower Na+ concentration,higher K+ concentration and K+/Na+ ratio,higher activities of SOD,CAT and POD along with lower MDA content of leaves.These results indicated that seeds pre-soaking with SA increased salt-tolerance of wheat seedlings by maintaining a higher K+/Na+ ratio,enhancing SOD,CAT and POD activities and reducing the degree of membrane lipid peroxidation.