为了弄清木本蕨类植物桫椤对水分亏缺环境的适应性,选用3a生桫椤苗,通过盆栽控水进行持续干旱胁迫和复水处理,研究了干旱历时3,6,8d和复水历时3,6,9d时桫椤叶片渗透调节物质含量、丙二醛(MDA)含量以及抗氧化酶活性的变化规律。结果表明:1)随着持续干旱时间的延长,桫椤叶片可溶性糖含量、脯氨酸含量、超氧化物歧化酶(SOD)活性和过氧化物酶(POD)活性均呈先增大后减小的趋势,在干旱3d时达到最大值;桫椤叶片可溶性蛋白含量和丙二醛含量呈增加的趋势,在干旱8d时达到最大值;过氧化氢酶(CAT)活性呈先减小后增大的趋势,充分供水时活性最高。2)复水9d时,桫椤叶片可溶性糖含量、脯氨酸含量、POD活性和CAT活性已恢复并降低到充分供水时以下的水平;可溶性蛋白含量、MDA含量和SOD活性高于充分供水时。可见,干旱胁迫时,可溶性蛋白含量与充分供水时相比一直呈增加趋势,其在桫椤抵御干旱胁迫中发挥了相对重要的作用;可溶性糖含量、脯氨酸含量、SOD活性和POD活性快速响应干旱胁迫并增加,但干旱3d后即开始下降,说明桫椤对干旱胁迫的耐受能力相对较差。同时,复水后,各生理指标均迅速恢复到了充分供水时的水平,说明桫椤在遭遇干旱胁迫后具有相对较强的恢复能力。

In order to find out the adaptability of the woody fern Alsophila spinulosa to the water-deficient environment,three-year-old seedlings were selected and potted to control water for continuous drought stress and rehydration treatment.The changes of osmotic adjustment substance content,malondialdehyde(MDA)content and antioxidant enzyme activity in the leaves were studied after 3,6,8 days of drought and after 3,6,and 9 days of rewatering.The results showed that:1)With the prolongation of the continuous drought time,the soluble sugar content,proline content,superoxide dismutase(SOD)activity and peroxidase(POD)activity increased first and then decreased.The maximum value was reached at 3 days of drought;the contents of soluble protein and malondialdehyde increased gradually,and reached the maximum at 8 days of drought;The catalase(CAT)activity showed a trend of first decreasing and then increasing.Its activity was the highest when adequately watered.2)At 9 days after rehydration,the soluble sugar content,proline content,POD activity,and CAT activity had recovered to the levels below those under adequate water supply;the soluble protein content,MDA content and SOD activity were still slightly higher than those under adequate water supply.It could be seen that under drought stress,the soluble protein content had been increasing,which played a relatively important role in the resistance to drought stress;The soluble sugar content,proline content,SOD activity and POD activity responded rapidly and increased,but began to decline after 3 days of drought,indicating that the tolerance of Alsophila spinulosa was relatively poor to drought stress;At the same time,after re-watering,all physiological indicators quickly recovered to the level of sufficient water supply,indicating that Alsophila spinulosa had a relatively strong recovery ability after encountering drought stress.