根瘤形成中传递型表皮细胞的诱发及功能研究

The root of locust produced many changes after having inoculated with Rhizobia . Watch the root of locust inoculated with rhizobia after 2d at optics microscope and we will get the result that a few root hairs of some root segments will crook and expand slightly . The root hair will give birth to obvious deformation , some are like 'z',others take the form of calabash. The deformed root segments inoculated with Rhizobia were dyed with methylene blue , It was observed clearly that the position that Rhizobia invaded the seeding of locust is the top of root hair and it entered the cortex from the epidermis. Transfer cells can be induced by Rhizobia during the forming of root nodule of locust. They have nothing to do with the existence of the iron. Transfer cells with wall ingrowths which are well developed on the extangential wall in root epidermal cells are observed in the root segments which has distinctive deformation . During the formation of root nodule , transfer cells are first observed in the epidermal cells but also in the out 1~2 layers of exodermis even in root hair cells. They can exist until the formation of the root nodule. There are no transfer cell in the outer layers of the root nodule . But they can be observed near the root and in the front or at the back of the root nodule . Membrana ingrowth is first observed at the initial stage of the formation of transfer cells, then the wall material gradually deposits the membrana ingrowth, at last transfer cells formed and can last until the formation of the root nodule. Besides locust, the leguminous plants Albizia julibrissin , Astragalus sinicus , Medicago sativa can also be induced by Rhizobia , their root segments where root hairs grow densely and swell are selected to have a series of treatments ,at last they were made into semi-thin sections(3um) , the root cross sections were observed by optical microscope under the oil objective . The result shows that the wall ingrowth is very clear to be found .They are all the typical epidermal transfer cells. The fresh weight and the dry weight of locust is higher than the one without inoculation during the same period. The water content of locust without inoculation is lower than the one which inoculated with Rhizobia , while the difference is not obvious . Analyze the element content of roots of locust which are grown in an aqueous solution and we can know that the content of phosphorus, potassium ,magnesium, iron, manganese and zinc in the root of locust inoculated with Rhizobia are higher than the one without inoculation . It is mainly because the absorption of these elements has a direct bearing on the long and dense root hair and the transfer cells .

根瘤菌与豆科植物共生固氮是自然界生物固氮最有效的形式，一直是生物固氮研究的重点。多年来对共生根瘤的形态结构、生理、遗传已进行了广泛深入研究。但根瘤菌可诱发传递型表皮细胞尚属首次报道，传递型表皮细胞的发生与根瘤形成中水分、无机盐和营养物质的吸收运输有关。深入研究它们之间关系，可填补这方面空白，具有重要的理论价值。.

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