Adaptation Mechanism Of Different Chinese Fir Clones To Low Phosphorus Stress

At present, phosphorus has played an important role in agricultural and forestry production limits in all worlds. The traditional agricultural and forestry productions have met plants' phosphorus demands mainly by fertilizing and soil improvement, and have paid less considering in the improvement of plants phosphorus-utilize efficiency. So discover high phosphorus-utilize efficiency plants to substitute the traditional ways to improve the phosphorus-utilize efficiency has become an important task to be settled in currently forestry production.For the present status of buffering the soil declining caused by successive planting mainly by the improvement of soil condition to adapting Chinese fir growth, but not by selecting high fertilizer- utilize efficiency Chinese fir to adapting soil condition, this research primary collecting 14different nutritional efficiency genotypes, base on the investigating of fast-growing, fertilizer response of 125 Chinese firs clones and their filial clones, which are collected from whole country. The index of morphological and physiological was studied by pot test and solution culture under low phosphorus stress and compare the physiological response difference of different Chinese fir clones for fertilizer stress. Study the morphological and physiological response of different Chinese fir clones under phosphorus stress, seek the morphological and physiological adaptation mechanisms by which plant regulate the fertilizer absorbing and provide science foundation to the selecting of high phosphorus-utilize efficiency Chinese fir clones. The main results as follows:1. The morphological index of DBH , seeding height and dry matter distributing of different Chinese fir clones were studied under phosphorus deficiency stress. The results showed that the aggravation of phosphorus deficiency would lead to the decline of the DBH, seeding height, and the allocation of dry matter to roots have non-obviously increase. The morphological index showed distinct differences between different Chinese fir clones under phosphorus stress. Itwas found that 37, 8, 24 with the highest productivity under low phosphorus was excellent clones with the least sensitivity to phosphorus supply, which may be adapted in low phosphorus environments, while clones 3 , 5, 23 , 34 were sensed to phosphorus stress, which may grow well under the phosphorus abundant environment and the growth would be obviously affected under stress condition. The morphologic index of No.9 clones showed a medium character between the two types clones.2. Compare the physiology-ecological responses of different Chinese fir clones, the results showed that the intensity of activities of acid phosphatase, rhizosphere acidification, P kinetic parameters and the photosynthesis-respiration rate are all changed by phosphorus stress. In stress environment, the intensity of rhizosphere acidification was stronger and PH in rhizosphere was decreased obviously, the activities of acid phosphatase were higher than those under normal P treatment. With the amelioration of phosphorus, the Imax, decreased while Km and Cmm increased in all clones, the chlorophyll contents and photosynthesis rate decreased considerably, and the respiration rate and CO2 compensation points were enhanced responsibly.3. The correlation of morphology and physiological ecology indexes of different Chinese fir clones under phosphorus stress were studied. The results showed that the morphology and physiology7 ecological indexes of different Chinese fir clones have certain correlations. Besides the negative correlations of root-hat radio and decline data in rhizosphere PH, the remarkable positive correlation of seedling high and chlorophyll, other indexes didn't show obvious correlations. The physiological ecology indexes of decline data in rhizosphere PH and the activities of acid phosphatase in leaves and in rhizosphere submitted remarkable positive correlation, and the correlation coefficient were higher; there were also remarkable positive correlation in the activities...