不同抗性苹果砧木叶片抗坏血酸代谢对干旱胁迫的响应

以抗旱性强的苹果砧木新疆野苹果Malus sieversii (Ledeb.) Roem.]和抗旱性弱的平邑甜茶M.hupehensis (Panlp.) Reld.]叶片为试材,在20%PEG-6000模拟干旱胁迫条件下,研究了抗坏血酸(AsA)含量、氧化还原状态、合成和代谢相关酶活性对干旱胁迫的响应。结果显示,在正常水分条件下,新疆野苹果和平邑甜茶叶片间AsA含量及代谢相关酶活性差异不显著。干旱胁迫过程中,二者之间叶片AsA、谷胱甘肽(GSH)、总谷胱甘肽和总抗坏血酸含量变化趋势基本一致,但新疆野苹果叶片中的含量增加幅度明显大于平邑甜茶;且与平邑甜茶相比,新疆野苹果叶片具有较高的L-半乳糖酸-1,4-内酯脱氢酶(GalLDH)、脱氢抗坏血酸还原酶(DHAR)和谷胱甘肽还原酶(GR)活性及AsA/DHA(脱氢抗坏酸)和GSH/GSSG(氧化型谷胱甘肽)比率。研究表明,干旱胁迫下,新疆野苹果能够维持较高的AsA合成和再生能力,并具有维持高AsA水平特性,这可能与其具有较强的抗旱性相关。

Response of Ascorbic Acid Metabolism in Apple Rootstocks Leaves under Drought Stress

To investigate relationship between the ascorbate content and to anti-drought of apple rootstockes,we studied the changes of ascorbate and glutathione and key enzymes activities of AsA biosynthesis and recycling were studyed in Malus sieversii(drought-resistant variety) and M.hupehensis(drought-sensitive variety) seedlings under drought stress.The results showed that ascorbate contents and activities of related metabolism enzymes did not have significant differences between M.sieversii and M.hupehensis seedlings in well-water condition.Under drought stress,the change trends of AsA,total AsA,GSH and total GSH contents were consistent in both of seedlings,but the increased extent of them in M.sieversii were more than that in M.hupehensis.The leaves of M.sieversii showed higher activities of GalLDH,DHAR and GR,and ratio of AsA/DHA and GSH/GSSG than that of M.hupehensis under drought stress.It was suggested that M.sieversii with higher anti-drought stress abilities is due to have capability of maintaining higher abilities of AsA biosynthesis and recycling than that of M.hupehensis under drought stress.