聚乙二醇模拟干旱对马铃薯幼苗生长与细胞膜透性的影响

Effect of PEG-induced water stress on morphologic characters and membrane permeability of potato

为探明马铃薯的抗旱机理,在离体培养条件下,对8个马铃薯品种进行5%、10%、15%、20%、25%、30%的聚乙二醇(PEG 6000)模拟干旱胁迫,研究马铃薯的茎叶发生、根系生长与细胞膜相对透性的变化。结果表明:随着PEG胁迫的加深,所有材料的叶片变小,除湘马铃薯1号外的其余7种材料的叶片数在10%～30%PEG胁迫下均显著少于对照;马铃薯株高对PEG胁迫最敏感,在5%～30%PEG胁迫下,8个马铃薯品种的株高均显著高于对照;在10%PEG胁迫下,除S.chacoense–1号外的其余7种材料的茎节数均显著少于对照,各材料的茎节生长开始受到影响;根系的伸长生长对干旱胁迫的敏感度高于根系数量,湘马铃薯1号在15%PEG胁迫下即表现出发根困难,中薯3号、东农303、费乌瑞它、金山薯的发根限制浓度为25%,而大西洋、中薯5号和S.chacoense-1号在胁迫浓度达30%时仍能正常发出根系,只是生长变缓;在5%～30%PEG胁迫下,随PEG胁迫的加深,8个马铃薯品种的细胞膜相对透性(电导率)均呈增加趋势,但增加幅度不同,表现出的规律与其幼苗形态表型基本相似。

The effects of water stress induced by polyethylene glycol 6000（PEG 6000） on morphological characters and membrane permeability of seedlings were studied using 8 varieties of potatoes. Each of the potato varieties was treated with 0（CK）, 5%, 10%, 15%, 20%, 25% and 30% PEG respectively. The results showed that leaf size and number decreased with increasing concentration of PEG. Leaf numbers of all the materials but Xiang Potato 1 were significantly lower than CK when treated with 10% PEG. The elongation of stems was more sensitive to drought stress, which were significantly inhibited by 5% PEG treatment compared to CK and intemodes number was susceptible to 10% PEG treatment. The root growth was more sensitive to drought stress compared to the number of root. The root of Xiang Potato 1 could not grow under 15% PEG stress and Zhongshu3, Dongnong303, Favorita, Jinshanshu were restricted by 25% PEG treatment. Interestingly, the roots of Atlantic potato, Zhongshu5 and S.chacoense-1 could develop even under 30% PEG stress. Membrane permeability of seedlings increased with increasing concentration of PEG. The level of drought resistance varied among varieties of potatoes. The results revealed that the effect of PEG-induced water stress on seedling morphology was in accordance with the effect on membrane permeability.