深山含笑对酸雨胁迫的适应性研究

Growth Adaptation of Seedlings of Michelia maudiaes Dunn to Acid Rain Stress

应用模拟酸雨溶液喷洒法和石蜡切片技术,研究了深山含笑幼苗在不同pH值(2.0,3.0,4.0,5.6(对照))的酸雨溶液胁迫下的生长情况(叶面积、苗高、根长等)和叶片解剖结构变化。结果表明:pH<3.0的酸雨溶液严重抑制幼苗的生长,植株出现明显的伤害症状,大量的苗木出现死亡;显微结构观察显示,叶表皮及叶肉细胞结构均受损或坏死。与对照相比,pH≥3.0的酸雨溶液处理对苗木的伤害较轻,可见性伤害症状不明显,显微观察结果显示仅表皮细胞受损。从生长指标来看,pH≥3.0的酸雨溶液对苗木生长有促进作用,呈正生物效应。

The effect of the simulated acid rain on the seedling of Michelia maudiae Dunn was studied by the spray experiment and wax dissection technique. The growth responses （leaf area, seedling height, and root length） and leaf anatomical structure of the seedlings in different simulated acid rain treatments were compared. The result showed that the seedling growth were seriously depressed in the acid rain with pH value 〈 3.0. The leaves presented injury symptoms; many seedlings died. Some of the epidermal and vascular bundle cells were found broken or necrosis under microscopy. By comparison, in the treatments with pH values greater than 3.0, the seedlings exhibited minor symptom. Visible damage was not clear; only epidermal cells were damaged. Based on the growth parameter, acid rain with pH value between 3.0 -4.0 could stimulate the seedling growth, which was dominated by a positive effect.