Study On The Effect Of Nutrition Element On Drought Resistance Of Fraxinus Mandshurica

Fraxinus mandshurica was used as material which was treated with different concentrations of spray potassium phosphate,calcium chloride and fertilized with N,P.,K compound fertilizer through simulating natural drought stress in experimentation.We studied the change in relative conductivity,leaf water potential,photosynthetic rate,transpiration rate,water use efficiency,stomatal conductance,soluble protein content,soluble sugar content,SOD and POD activity.The results as following:1.The fraxinus mandshurica that was treated with calcium chloride solution in suitable concentration was better than no treatment group in photosynthesis,relative conductivity,leaf water potential,photosynthetic rate,transpiration rate,water use efficiency,the content of osmoregulation substance,SOD and POD activity significantly,we found that the suitable concentration of calcium chloride solution was 0.1%to 0.4%.2.The fraxinus mandshurica was treated with different concentrations of spray potassium phosphate through simulating natural drought stress.The relative conductivity increased,other physiological traits including leaf water potential,photosynthetic rate,transpiration rate,water use efficiency and stomatal conductance have descended in different degree.By comparing and analyzing,we found that:P(P₂O₅) 10mmol·L^-1and K(K₂O) 15mmol·L^-1 can abate the adverse reaction caused by water stress to fraxinus mandshurica and enhance the resistance of plants to water stress.3.During the quadratic regression rotational experiment,we studied the photosynthesis and chlorophyll content of fraxinus mandshurica which fertilized with N,P,K.We obtained the multiple regression equation of the physiological index under the different water condition.We found that:When the soil water content was 34%,the effect of N,P,K to fraxinus mandshurica was equilibrium.As the decreased of water condition,the effect of P and K was become more significant,and the effect of P was earlier than K.When the soil water content was 12%,the effect of P,K was much higher than N,but the dosage of N,P,K mustn't be excessive.By statistical optimizing,we could found that:As the decreased of water condition,the best proportion of N,P,K:N(urea) 89.2-106.1 kg/ha,P(P₂O₅)44.7-45.0 kg/ha, K(K₂O) 63.1-67.1 kg/ha.