Hg^(2+)污染对莼菜冬芽幼叶细胞超微结构伤害的研究

A Study on the Damage of Hg^(2+) Pollutant to the Ultrastructural Changes of Young Leaves of Brasenia schreberi Winter Bud

报道了Hg2 +污染对莼菜冬芽幼叶毒害引起的叶片受害症状和叶肉细胞的超微结构变化。冬芽在Hg2 +浓度 5mg/L处理 15d时 ,叶片开始褪绿 ,腺毛收缩扭曲 ,粘液减少 ,细胞中高尔基体消失 ,核糖体减少 ,线粒体出现解体。在相同处理时间中 ,随着Hg2 +浓度增加 ,细胞出现质膜收缩 ,胞间连丝断裂 ,核仁裂解成多个小核仁 ,叶绿体膨胀 ,类囊体解体。在Hg2 +浓度 15mg/L时 ,细胞核解体 ,细胞死亡。经观察 ,Hg2 +对莼菜冬芽毒害的致死量在 2 5～ 5mg/L。

The symptoms of the young leaves and ultrastructural changes of mesophyll cells of Brasenia schreberis winter buds when induced by poisoning of Hg 2+ pollution are reported in this paper. When winter buds were treated with a concentration of Hg 2+ in 5mg/L solution within 15 days, the leaves gradually lost their green color; glandular hairs contracted and twisted and mucilagenous material of the leaves was greatly reduced. The ultrastructural changes of the mesophyll cell showed the disappearance of Golgi apparatus and reduction of ribosomes with integration of mitochondria. Increasing of Hg 2+ concentration on the same days of treatment as above,caused changes in the ultrastucture of the cells.It showed contraction of plasmalemma and snap of plasmodesmata, nucleolus broke into several parts, chloroplasts swelled and thylakoids disintegrated. When winter buds were treated with concentration of Hg 2+ increased to 15mg/L, the nucleus of cell broke down and cells died.According to our observation, the lethal concentration of Hg 2+ to the winter bud of B. schreberi ranges from 2 5 to 5mg/L.