Studies On Water Stress Of Liriodendron Seedling Physiology Effects

The drought stress(four treatment level of the Soil moisture , respectively the contain of soil on the field capacityâ‘ W1: 20%±5%,â‘¡W2: 40%±5%,â‘¢: 60%±5%, â‘£: 80%±5 %),waterlogging stress(the water level higher 2—5cm of the seedling root), waterlogging stress and drain(drain after waterlogging four days) of Liriodendron. chinense Sarg,L.chinense x L.tulipfera.,L.tulipifera L , annual seedling three different variety/four provenances were studied, by overall and systematic comparative analysis on the photosynthetic characters and physiological biochemistry traits, the purpose is to provide theory basis for the future scientific management and culturing high quality seedlings. By testing and analysis of many indexes, the results as follows:1,The injury of the Liriodendron chinense seedling under drought stress is more serious with the soil moisture, from the livability and whole behavior, the sequence of drought resistance from the high to low is: the L.tulipifera L(North Carolina)> L.chinense x L.tulipfera. > L.tulipifera L(Louisiana)> Liriodendron Chinense; During the course of waterlogging experiment, the leaves Wilting,drying-up, reaction time of turning yellow on the different Liriodendron. chinense seeding are different, change degree is also different. On the whole, the sequence of waterlogging resistance: L.chinense x L.tulipfera.> L.tulipifera L(North Carolina) > L.tulipifera L(Louisiana )> Liriodendron Chinense. The injury degree of L.chinense x Ltulipfera. and L.tulipifera L(North Carolina) are smaller in the drain after waterlogging four days and recovery faster.Water stress brought significant effect on transpiration rate,net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration of the Liriodendron. chinense, all indexes have significant difference along with the soil water content and different waterlogging time. Generally, variance regular of Pn,Gs,Tr are similar, But Ci is contrary. Following the air exchange model of the photosynthetic action, the results show: the great decrease of net photosynthetic rate owe to stomatal conductance decline and photosynthetic ability decrease of mesophyll cells.3, The root vigor,Conductivity SOD vigor, POD vigor,MDA content of different provenances have significant difference. The root vigor of L.tulipifera L(North Carolina) is highest; The effects of the Conductivity SOD vigor, POD vigor of L.chinense x L.tulipfera. are smaller; however ,the MDA content shows decreased trend.4,The chlorophyll contents among different provenance under drought stress rose in the early stage and decreased then, decrease extent of L.chinense x L.tulipfera. is slowly ,Liriodendron Chinense serious; The chlorophyll contents among different provenance under waterlogging stress decreased with the stress time increase, the sequence of the waterlogging resistance is: L.chinense x L.tulipfera.> L.tulipifera L(North Carolina)> L.tulipifera L(Louisiana)> Liriodendron Chinense.5,The proline content among different provenance under drought stress has significant...