龙眼幼苗铝吸收特性的研究

Characteristics of Aluminum absorption by Longan (Dimocarpus longan) seedlings

铝胁迫下龙眼幼苗铝吸收特性试验表明:龙眼铝吸收特性取决于介质中铝的浓度,介质浓度≤0 3 70mmol·L- 1 时,龙眼铝吸收主要受代谢控制,属于主动吸收;介质浓度>0 3 70mmol·L- 1 时,则主要受非代谢因素影响,即为被动扩散。铝胁迫下,龙眼吸收的铝主要集中于根系,根的铝含量是茎的3 5 4～5 6 6倍,是叶片的3 .6 0～5 80倍,其积累量占全苗铝总积累量的5 8 85 %～75 0 7%,且随铝浓度的提高根中铝含量、铝积累量均大幅度增加,根吸收的铝转移到地上部的比例随介质铝浓度的提高而减小。铝在龙眼叶片细胞中主要分布在细胞壁,铝胁迫下龙眼叶片细胞壁中的铝含量占86 2 0 %～88 5 8%,依次是细胞质、叶绿体、线粒体,核蛋白中最小。

The effects of aluminum stress on aluminum absorption of Longan( Dimocarpus longan ) seedling were studied. The results showed that the characteristics of aluminum absorption depended on the concentration of aluminum in the medium. At the low concentration (≤0 370 mmol·L -1 ), aluminum uptake was dominated by metabolism. When aluminum concentration was higher than 0 370 mmol·L -1 , aluminum uptake was mainly controlled by non metabolic factors. Under aluminum stress, the aluminum was taken by Longan mainly accumulated in root. The content of aluminum in root was as 3 54～5 66 times as that in stem, and as 3 60～5 80 times as that in leaves. As the concentration of aluminum in the medium increasing, the content and accumulation of aluminum in root increased greatly, however, the part taken by root and transferred to up ground decreased. The aluminum mainly distributed in cell wall of Longan leaves. Under the aluminum stress, the content of aluminum in different parts of cell was in the order as: cell wall>cytoplasm>chloroplast>mitochondrion>nuclear protein. The content in cell wall was the highest, which reached to 86 20%～88 58% of total accumulation.