Study On The Photosynthetic And Water Physiological Characteristics Of Different Sea Buckthorn Cultivars

Sea buckthorn is a drought tolerance species in china. During the long period of living and evolution, it has been formed a strong adaptability to the environment. The research studied on the water and photosynthetic physiological characters of different Sea buckthorn species, at the same time, probe into the water requirement regularity and the drought resistance of Sea buckthorn .These results will provided scientific basis for the foster of the growth of thorn and anti-drought afforestation. The results are as follows:1. The mainly growth characters: Different sea buckthorn cultivals will achieve the first growth peak from the middle ten days of a month to the last ten-days of a month of June. Then descend suddenly, approach or achieve the minimum pot in the period of observation time. After that, there have a gradually ascend tendency. The second peak will form from the middle ten days of a month of July to the last ten-days of a month of August,this stage will last a long time, and at the same time, the Sea buckthorn will complete a half growth capacity of the whole year. Then decline again until the Sea buckthorn stop grow. The exception of these, the capextend of trees also has the same tend like this.2. Tissue parameters in leaves of different sea buckthorn cultivars were observed. The results showed that differences of leaf thickness, stoma density, stockade tissue thickness, ratio of stockade tissue thickness to sponge tissue thickness, CTR, SR, and size of upper epidermis cells and etc. are significant while differences of epidermis thickness, cutin layer thickness and stoma length were not.3. The research on photosynthetic physiology of sea buckthorn showed that: whatever in fuxin or in shenyang have obvious diurnal variation and season variation. There displayed a obvious midday-depression and double peak curve on bright sunny days in summer under normal cultivations .The net photosynthetic rate increased rapidly for a few hours after sunrise , reached a peak at about 12 A.M. , with was followed by marked decrease until about 2 EM. ,then increased again and reached a second but lower peak at about 3 EM.In addition to it,the maxium will appear at Auguest and the minimum will appeat at september.4. The research on water physiology of sea buckthorn showed that: during the whole growth seasons, the leaf water content had little change. The range from 63.6% to 72.04%, They all displayed parabolic shape, which peak value was at 11:00. The decreasing range of water content and water potential was small, and leaf growth rate of side shoot and photosynthesis rate in a higher level under the medium water stress area like fuxin, which showed the typical physiological character belonging to drought-enduring plant, In addition, The changes of transpiration in a day showed a single-peak curve, furthermore, the peak appear at the 2 P.M.5. Take advantage of principal component analysis, evaluate the drought resistance of sea buckthorn, we can conclude that liaoful has the strongest drought resistance.