Studies On Introduction And Drought Resistance Of Three Plants In Spiraea L.

Spiraea trilobata L., Spiraea salicifolia L. and Spiraea dasyantha Bge., belonging to Spiraea L. family in Rosaceae, are perennial defoliate shrubs with colorful flowers, cold resistance and drought resistance so that they could be perfect ornaments and be applied in city gardening. The systematic researches on the growing period and the biological character at every period provide theoretic direction and technical support in the fields of breeding, reproducing and its application in gardens. In this paper, some researches on the seed configuration, seed germination and seedling growth process were done through experiments. At the same time, the anatomical structures and physiology and biochemical characteristics were observed and analyzed in the thesis. The main results were as follows.1. Three kinds of seeds, minimal, germinated more quickly in water. The experiment gave the water temperature of the highest germination rate: Spiraea trilobata L.: 20 ℃;Spiraea salicifolia L.: 20℃;Spiraea dasyantha Bge.: 60℃. So the seeds can be treated with those methods to increase the germination rate.2. The height growth of three kinds of seedlings had the trend of "S" curve, so was the diameter growth. The growth cycle included four stages: seedling emergence stage;initial stage;rapid growth stage;later growth stage. The sequence of growth velocity of three plants was Spiraea trilobata L.>Spiraea dasyantha Bge.>Spiraea salicifolia L., so was the sequence of accretion. The results showed three plants grew normally and well, and had drought resistance and cold resistance.3. There was a close relation between anatomical structures of leaves of three plants and their drought resistance. They all had thick cuticle, dense stomatas, dense palisade tissue, developed mechanical tissue, and much cytoplasm in the cells. Spiraea trilobata L. had sunk stomata and strumae on the lower epidermis cells, which could help it resist the drought. The two-layer cells of the lower epidermis, sunk stomata, and mechanical tissue could help Spiraea salicifolia L. resist the drought. Spiraea dasyantha Bge. had much epidermis hair on both sides of leaves, and there were strumaes on the surface of the lower epidermis cells.4. Robinia pseudoacacia L. and Gleditsis microphylla Goraon have high drought resistance ability, so the paper compared the physiological and biochemical indexes among five plants, and made a comprehensive evaluation about drought resistance. The droughtresistance of three plants in Spiraea L. was close to Robinia pseudoacacia L. and Gleditsis microphylla Goraon through the comparison of SOD, POD activity and MDA content. The drought resistance of three plants and Robinia pseudoacacia L. was close through the comparison of protein content. Through the comparison of soluble sugar content, the drought resistance of Spiraea trilobata L., Spiraea dasyantha Bge. and Gleditsis microphylla Goraon was close, so was the drought resistance of Spiraea salidfolia L. and Robinia pseudoacacia L.. The drought resistance of Spiraea dasyantha Bge., Spiraea salidfolia L. was close to Robinia pseudoacacia L. and Gleditsis microphylla Goraon through the comparison of chlorophyll content. So the results showed that three plants of Spiraea L. had high drought resistance ability.5. The levels of drought resistance of three plants from high to low were as follows: Spiraea dasyantha Bge.>Spiraea trilobata L.>Spiraea salidfolia L.. So the three plants can be planted in the hotter place to beautify the city.