黄瓜根边缘细胞生物学特性及其对铝的响应

 以黄瓜为试验材料, 研究了黄瓜根边缘细胞的生物学特性及其对铝毒的响应。试验结果表明,在黄瓜种子萌发过程中, 根边缘细胞有很高的活性。当根长度在25 mm, 根边缘细胞数目达到最高值5 480个, 根伸长到10 mm时, PME (果胶甲基酯酶) 相对活性达到最高值, 然后随着根的伸长, PME相对活性逐渐下降。在铝处理的条件下, 黄瓜根长及边缘细胞的存活率会随着铝液浓度的升高依次递减, 说明铝毒对根的发育有明显的抑制作用及危害, 而根冠的PME活性却有所提高, 说明了PME与植物铝毒胁迫之间存在着相关性。铝毒条件下边缘细胞PME活性的提高, 使细胞壁的果胶去甲基化, 增加了Al³⁺的结合位点, 从而避免铝更多地进入细胞内, 造成对植物的毒害。

Biological Characteristic and the Response to Aluminum Toxicity of Cucumber Border Cells

Biological characteristic and response to aluminum toxicity of cucumber (Cucumis sativa) root border cells have been studied. The experimental result indicated, during the sprout process of cucumber seed, the root border cells had very high viability. When the root length was 25 mm, the number of the root border cell reached its maximum (about 5 480). The relative activity of PME (Pectin methylesterase) reached the maximum at 10 mm root length, then decreased gradually with the root elongating on. With the increasing concentration of Al~ 3 , root length and survival rate of border cells decreased. These results showed that aluminum toxicity had the obvious inhibition and harm to the growth of root and border cell. However, PME activity enhanced with the increasing concentration of Al~ 3 , showing PME was related to the stress of aluminum on plant. Simultaneously, the increase of PME activity under aluminum treatment condition caused demethylation of pectin in cucumber cell wall and increased Al~ 3 union position spots in the cell wall, thus prevented much more aluminum from entering the cell and harming plant.