Ecological Adaptability To The Eat Ofkubuqi Desert And Eco-Economic Value Analysis Of Four Sand-Fixing Plants

This thesis made a systematic research on physiological characteristics, morphological structure, competition ship of Hedysarum fruticosum vat. lignosum, H. scoparium, H. fruticosum and Artemisia ordosica in the east of Kubuqi Desert of Ordos Plateau where has serious desertification. In light of ecological adaptability and eco-economic value analyze the difference of four plants. The main results are as follows:1. The diurnal variation of the net photosynthetic rate and transpiration of three Hedysarum plants were double-peak model in May, they all produce osmotic adjustment substances to decrease their water potential to enhance their ability to absorb water, improve water condition, increase antioxidant enzyme activitiy, so that the photosynthesis activity were protected. Where Artemisia ordosica is concerned, its photosynthesis rate and transpiration keep close correlation with soil water content.2. Drought resistant order of four plants was presented by analyzing their damage: Artemisia ordosica＞H.scoparium＞H. fruticosum var. lignosum＞H. fruticosum.3. There are xeromorphic structures, such as thicker cuticle, and the Artemisia ordosica is more thicker than other three Hedysarum plants. Developed round palisade tissue. Degraded sponge tissue distribute between the vein of three Hedysarum plants, however the sponge tissue of Artemisia ordosica changes into water storage tissue. There are 3 or 4 layer of sclerenchyma under phloem of dense vein of three Hedysarum plants, and there are one midrib and two side vein in the Artemisia ordosica's leaf, under it are several layer of sclerenchyma. There are some special cells that contain colloidal substance in the leaves of three Hedysarum plants.4. Three Hedysarum plants show excellent adaptability to mobile dunes, while Artemisia ordosica distributes on fixed dunes, so moving sand can't damage it.5. There is no competition ship between H. fruticosum var. lignosum and Artemisia ordosica. Artemisia ordosica has no distinct influence on clone reproduce of the one. However, Artemisia ordosica restrain its seed sprouting and seedling growing.6. Three Hedysarum plants all have higher feeding and greening value. Also, they can be used to make paper and wood-based panels, so they have higher economic value. Meanwhile, they can reduce wind, stabilize sand, improve soil, they have higher ecological value and less cost. Artemisia ordosica can reduce wind, stabilize sand, increase organic matter and nutrient matter, however its surface root prevent precipitation infiltrating into soil, and arose erosion. Due to soil moisture decreased, community dead after years. It is costly to develop its high oil content in seed, and Artamisia sphaerocephala Krasch gum andα-VE. 7. The inhibitory experiment of Artemisia ordosica based on orthogonal latin square(L₉3⁴) shows: cutting off surface and shading have no effect on its inhibition, and its chlorophyll content increases under shading, shows its excellent environmental plasticity.