菟丝子初生根发育与退化

对寄生植物菟丝子初生根的发育与退化研究结果表明:菟丝子种子具胚根,由它形成初生根.根尖不存在根冠和典型的分生区等,根毛着生在根的最前端,由表皮细胞外突而成.初生根的生长未见细胞分裂,仅是细胞的伸长和中柱的分化。菟丝子的种类不同,幼苗的生长对根的依赖程度也不同.幼苗萌发后3d,初生根开始退化。在退化之前,细胞器等解体成可溶性物质,连同贮存的营养物质通过中柱转运到幼苗的上部。文中讨论了营养物质在幼苗体内再利用和根的退化对寄生的意义。

DEVELOPMENT AND DETERIORATION OF PRIMARY ROOT OF PARASITIC PLANT DODDER

This paper is dealt with the development and deterioration of primary root of parasiticplant-dodder.The results show that the root differs from a normal root of green plant:no root capand meristermatic region;root hairs on top developed from only some epidermal cells.The growth of pri-mary root is in such a manner as lengthening and differentiation of cells.Seedlings grow in some degree rela-tive to their roots.3 days after germination,cells in root tip begin to disintegrate into soluble substances,which are translocated to upper part of seedlings and stored for reuse.The reuse of nutrient and degernationof root were both significant for seedling parasitism.It was proposed that root of parasitic plant was arudimentary organ,which was the result of simplification,but not only of deterionation during plant evolu-tionary process.