甘薯品种抗旱性生理指标及其综合评价初探

Studies on Several Physiological Indexes of the Drought Resistance of Sweet Potato and Its Comprehensive Evaluation

采用土壤干旱和室内PEG水分胁迫测定相结合的办法,研究有关生理指标与甘薯抗旱性关系。结果表明,水分胁迫下伴随着叶片相对含水量(RWC)的明显下降,丙二醛(MDA)含量显著增加,质膜相对透性(RPP)急剧上升,而过氧化氢酶(CAT)活性迅速下降;抗旱性强的品种叶片RFP和MDA的增加幅度显著低于不抗旱品种,而前者叶片RWC和CAT活性的下降速度显著慢于后者。并具有比后者较强的渗透调节能力,中等抗旱品种介乎两者之间。所选的五种生理指标与抗旱性的相关性次序是:RWC>CAT>RPP>可溶性糖>蛋白氮,这5种指标的隶属函数加权平均值(D值)与抗旱系数间的相关系数达极显著水平(r=0.956、P<0.01),其中前三者对抗旱性评价的累计贡献率达78％(以r权数计),其D值可近似代替五项指标。室内条件下的D值可用于甘薯品种的抗旱性评价与分级。

The effects of water stress on several physiological indexes in the lab . and the relationship between those indexes and drought resistance in the field were studied with nine sweet potato varieties. The results showed that malondialdehyde (MDA) content and relative plasmalemma permeability (RPP) increased and catalase (CAT) activity decreased with the decrease of relative water content (RWC) in the leaves, and the increases of RPP and MDA and the decreases of RWC and CAT activity in the leaves of high drought-resistance varieties were much less than those of poor drought-resistance ones which had lower ability of osmotic adjustment than the fomer under water stress condition. The correlative relationship between the physiological indexes and drought resistance of the varieties was in such order: RWOCAT activity >RPP>Soluble sugar>Protein-N. The correlation coefficient between the weighed average of subordinate function values(WAOSFV) of these five physiological indexes and drought resistance was highly positively significant (r=0. 956, P<0. 01), and three of the indexes, RWC, CAT and RPP, could approximately substitute for the five indexes. The results also suggested that the comprehensive physiological indexes for water stress in the lab. might be used for evaluation of the drought resistance of sweet potato varieties in the field.