3种桉树幼苗叶片养分变化及其转移特性

Dynamics and Transfer of Nutrients in the Seedling Leaves of Three Eucalyptus Varieties

Nutrient dynamic and transfer characteristics of trees reflect the preservation and utilization of nutrients,and the adaptability to the infertile soil and environment.The change of nutrient content and the transfer ratio of element N,P,K,Ca,Mg in living and fallen leaves of three Eucalyptus varieties of 184-1,201-2,guanglin-9 were measured and analyzed.The results indicated that the content of N,P,K,Ca,Mg in leaves was significantly different monthly within a year.In general,the nutrient content and the transfer rate of the leaf were relatively higher in the growing season（6-10 months）than that in other seasons.The nutrient content in the living leaves was significantly higher than that of the fallen ones,and the nutrient content in the living leaves was positively correlated（r=0.94,P<0.01）with that in the fallen ones.The nutrient content and the transfer ratio were different among the three varieties of eucalyptus.Contents of N and Ca were the highest in 184-1,and contents of P,K,Mg were the highest in 201-2,while contents of the other four elements except N were the lowest in Guanglin-9.In terms of the nutrient transfer rate,Ca had no change,and the rate of the other four elements was P>N>K>Mg and the difference was significantly different（F=192.19,P<0.01）.The nutrient content of the leaf was significantly(t=2.97> t 0.025 6=2.446 9),however the nutrient transfer rate was not remarkably affected by fertilization.There was no significant difference in the nutrient transfer rate among the three Eucalyptus varieties.The results showed that the changes of leaf nutrient content and the transfer rate were related with many factors,such as growth characteristics and biological characteristics of species and external conditions.