Comparison Of The Evolutional Structure Of Elaeagnus Angustifolia L. In Different Ecological Environments

In this article, the author uses the technologies of paraffin section, three sections of wood and wood maceration to research the leaves, young stems, petioles and secondary xylem of Elaeagnus angustifolia L. growing in four different kinds of ecological environment which are nursery soil, soil mixed with 1/3 saline alkali soil, 4/9 manure and 2/9 sandy soil, soil mixed with 1/2 saline alkali soil, 1/4 manure and 1/4 sandy soil, and saline alkali soil. The results and the statistics are analyzed by microscopic photography and SPSS 20.0.The results show that the cuticle of stems, leaves and petioles of Elaeagnus angustifolia L. increased with the growth of the content of saline alkali. Cuticle can reduce transpiration and influence water utilization and the temperature of the leaves. These advantages can help Elaeagnus angustifolia L. growing in saline alkali land absorb and use water to avoid physiological drought. With the increase of the content of saline alkali, the leaf thickness, the palisade tissue thickness, the palisade tissue cell layers, and the sponge tissue thickness of Elaeagnus angustifolia L. grows. This indicates that the plant generates enough nutrition by increasing leaf thickness, especially by increasing the number and area of palisade tissue, to adapt to the saline environment. With the increase of the content of saline alkali soil, the equal diameter of xylem conduit aperture in the stems, leaves and petiole of Elaeagnus angustifolia L. increases, and the wood ray of Elaeagnus angustifolia L. broaden. The increase of the conduit diameter may reduce the resistance of plant conduction to make the uptake of water easier. In addition, widening wood ray may strengthen the ability of the products transporting photosynthesis. These are beneficial for the plant to adapt to the saline environment. Comparing of the mechanical tissues, the author discovers that with the increase of the content of saline alkali soil, the content of the mechanical tissues in the stems and petioles of Elaeagnus angustifolia L. increases, and the type of the mechanical tissues develops from collenchymas to sclerenchyma. Lacking of water, the mechanical tissues of the plant may exert a great effect on helping it maintain certain turgor and support to live through the state of water shortage.In conclusion, the morphological and structural features of Elaeagnus angustifolia L. are highly related to their living environment. Due to high salinity, the form and anatomical structures of Elaeagnus angustifolia L. growing in saline alkali soil must be different from those growing in other soils. This may also cause the plant to form some evolutional structures which can adapt to Saline-alkali stress resistant.