Effects of different phosphorus concentration on Caragana microphylla seedling growth and development

A solution culture experiment in growth room was carried to study the effects of different phosphorus concentration on Caragana microphylla Lam.seedling growth and development.The results indicated that the main root length,number of lateral roots,seedling height,rootshoot ratio,fresh and dry weight in shoot,phosphorus concentration and uptake in shoot,and Puse efficiency were significantly influenced by different P levels in nutrient solution.The suitable,optimal and critical value of phosphorus concentration in nutrient solution were 10~500 μmol·L-1,100 μmol·L-1 and 1~10 μmol·L-1 respectively,confirmed by comparing and analyzing the status of seedling growth and development and the difference of seedling main properties.The phosphorus content in shoot presented the trend of being increased at early stage and decreased at late with the increasing of phosphorus concentration in nutrient solution.When phosphorus concentration in nutrient solution reached 1 000 μmol·L-1 the growth of seedling would be restrained to a certain extent.