| Seedling vigor means a present or potential ability that the seedling can grow a nd d evelop n ormally. In t his a rticle, t he 1 aws o f morphological and physiological change of seedling under normal and threatening conditions were studied with the material Corylus heterphylla Fisch and Corylus avellana L. By comprehensive analysis, the indexes for evaluating filbert seedling vigor under different circumstances were selected. These indexes would provide scientific theoretical basis to judge the seedling vigor.This test was divided into two parts, dormancy phase and growing phase. In the dormancy phase, the experiment was done with the filbert drying in the air. In the growth phase, the waterlogging experiment was carried out and the dynamic rule of filbert developing was mensurated.The results were as follows:1. In the drying test, with the drying time prolonged, the water content in the shoot, stem, and root decreased; the plant surviving rate dropped; the budding time delayed and the growing amount reduced. If the seedling lost too much water, the buds would shrink in the later time. And even the seedling survived, the serious lack of water would have obvious effect on the growth and b iological q uantity. With t he c orrelative a nd factor a nalysis, all ndexes were contrasted and some indexes were selected to evaluate the vigor of the seedling. These indexes included water content of shoot and root, branch water potential, survival rate, shoot length and total buds. During the conservation of seedling, the less the time drying in the air, the less the water loss of plant, it was better to evaluate the vigor of seedling with the index branch water potential. If the drying time was too long and the plants lost too much water, the water content of shoot and root could be used to value the vigor of seedling.By the regression equation of survival rate with water content, the future survival rate could be predicted. And this survival rate might be used to evaluate the seedling vigor further. After the seedling were planted, it was necessary to use factual survival rate, total buds and the length of new shoot to value the Cory 1 us heterphylla Fisch seedling vigor.2. The results of waterlogging test showed that the content of proline in filbert leaves and the conductance rate of root increased with the time of threaten prolong. However, the root vigor and SOD rose at the earlier state, and then decreased when the waterlogging enhanced. These results indicated Corylus heterphylla Fisch could adapt the waterlogging condition in some certain degree, but its regulative ability was limited. During the course of waterlogging, root vigor dropped; the cell membrane was damaged and the capability to eliminate active oxygen decreased. After 16 days waterlogging stress, the root was still not rotten and the plant was not dead. This showed Corylus heterphylla Fisch had great ability to resist waterlogging. According to correlative analysis, conductance rate, content of proline and root vigor were selected to be the indexes to value seedling vigor.3. According to dynamic measuration of morphological indexes, regression simulation of yearly growing rule was done on seedling height and diameter. It was found that the coefficient of correlation was above 0.9, therefore, the trade of seedling growth could be forecast by regression equation. In the course of filbert growth, the metabolic laws of physiological indexes were different. The content of chlorophyll a, chlorophyll b and total chlorophyll varied as "low -high-low", on the contrary, the content of soluble sugar varied as "high-low-high". The dynamic variation of SOD and soluble protein presented as double apexes curve. By factor analysis, three main physiological indexes were chosen to value the seedling vigor. They were the content of total chlorophyll, comparable activity of SOD and solubleprotein. According to correlative and factor analysis on morphological and physiological indexes of two yearly Co\rylus heterphylla Fisch, seedling height,... |
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