Carbon Assimilation, Partitioning and Bioaccumulation in Ruellia tuberosa Plants Under Coal-Smoke Pollution

摘要

Coal-smoke pollution caused by the emissions of a thermal power plant affected the growth of Ruellia tuberosa L. during different stages of development. The length and dry mass of roots and shoots, as also the length of fibres and the length and width of vessel elements in the wood were reduced at the polluted site. Shoot elongation was inhibited more severely than root elongation as the root-shoot length ratio was greater at the polluted site in each stage of plant development. However, root-shoot dry mass ratio was raised only in pre-flowering stage and declined in the later stages. The nitrate reductase activity and protein content were highly reduced, whereas nitrate level was raised under the pollution stress. Sugar level was always lower in the stem than in roots and leaves; it declined at the polluted site in general. Sulphur content was invariably greater in all plant parts at the polluted site. Copper content was maximally affected by the polluted condition during the flowering stage of the plant. It normally decreased in roots and increased in stems and leaves. Zinc concentration also showed a similar variation pattern, but iron concentration was low in roots and leaves and high in stems under the polluted condition.