碱胁迫对羊草和向日葵的影响

Effects of alkali-stress on Aneurolepidium chinense and Helianthus annuus

以抗盐碱性较强的单子叶植物羊草和双子叶植物向日葵为材料,对其进行中性盐、碱性盐和各种中碱性混合盐等胁迫处理,以日相对生长率(RGR)为主要胁变指标分析各种胁迫的特点及其相互关系.结果表明,碱性盐胁迫与中性盐胁迫实际上是既相关又有本质区别的两种不同胁迫,应该将碱性盐胁迫定义为碱胁迫,而将中性盐胁迫定义为盐胁迫.碱胁迫区别于盐胁迫的关键是高pH值.以缓冲量作为碱胁迫的胁强指标,而以盐度作为盐胁迫的胁强指标较为理想.盐碱混合胁迫时,两种胁迫表现出协同效应.

Employing monocotyledon Aneurolepidium chlnense and dicotyledon Helianthus annuus, the two species with high alkali-saline resistance as test materials, and stressing them with neutral, alkalic, and mixed salts, this paper studied the characteristics of various stresses and their interrelations, with relative growth rate （RGR） as the main strain index. The results showed that under the same concentration, alkalic salt had a stronger effect than neutral salt, and the RGR of A. chlnense and H. annuus was decreased with increasing salt concentration under the same kind of salt stress and pH conditions. When the pH was higher, the RGR decreased more obviously. In addition, the proline and citric acid contents in test plants were increased with increasing stress. The transformation of proline in A. chinense was greater than that in H. annuus, while that of citric acid was in adverse. In a word, alkalic salt stress was different from neutral salt stress in stressing plants and in plant responses. Alkalic salt stress and neutral salt stress were actually two distinct kinds of stresses. The former was better called ＂alkalistress＂, while ＂salt-stress＂ only meant neutral salt stress. The key difference between them was their different pH value. It was reasonable to consider the buffer capacity as the strength value of alkali-stress, and the salinity as the strength value of salt-stress. An interactive effect between salt-stress and alkali-stress could be seen under mixed saline and alkali stress.