Effects of different phosphorus levels on date palm seedling growth, physiological indexes and nutrient elements contents

【Objective】This study analyzed the effect of different phosphorus（P） levels on date palm seedling growth, physiological indexes, nutrient elements contents to provide theoretical basis for developing balanced technique of fertilization of date palm seedling. 【Method】Selecting date palm seedlings as research material, a pot+nutrient solution experiment was conducted.The nutrient solution was set at 4 P levels with concentrations of 5（CK）, 100, 1000 and 5000μmol/L.The growth, physiological indexes and nutrient element conctents of the date palm seedlings were observed and measured after 7 months of cultivation. 【Result】Under the 5 μmol/L P level, the growth of date palm seedlings was weak.Under the 100 μmol/L P level, the fresh weight of root was significantly lower than that under the 1000 μmol/L P level（P＜0.05, the same below）. Under the 1000 μmol/L P level, the growth of date palm seedlings grew well, the fresh weight of root, dry weight of shoot, the increment of plant height, the P concentration of plant, the P accumulation of plant, the soluble protein concentration of the 3^rd and 6^rd leaves were significantly higher than those under CK. The newly sprouted leaves were dense, the P use efficiency of root and plant were the lowest under the 5000 μmol/L P level. Under the same P level, the P content in shoot tip was higher than that in leaves and root tip. The concentration of nitrogen（N）, potassium（K）, calcium（Ca）, magnesium（Mg）, sodium（Na）, aluminium（Al） in shoot and root were different under different P levels. With the increase of P level, the concentration of K, Al in shoot and root, and the concentration of Ca in shoot increased initially and then decreased, the concentration of Mg in shoot gradually increased, and the concentration of Ca and Mg in root gradually decreased. Under the 5000 μmol/L P level, the concentration of Na in shoot and root reached the highest. Under the 1000 μmol/L P level, the accumulation of N, K, Mg, Na and Al in the shoot, the N use efficiency in shoot, the Ca use efficiency in shoot and root were significantly higher than those under CK. 【Conclusion】The P level in nutrient solution affects the growth,physiological indexes, concentration,accumulation and use efficiency of nutrient element of date palm seedlings.Too low or too high P level is not conducive to the growth of date palm seedlings. Under 1000 μmol/L P level, date palm seedlings grow well.