›› 2003, Vol. 39 ›› Issue (6): 40-46.

• 论文及研究报告 •

### 杨树无性系根系吸收H2PO4-动力学特征与磷营养效率

1. 南京林业大学森林资源与环境学院,南京210037；中国科学院南京土壤研究所,南京210008
• 收稿日期:2001-12-11 修回日期:1900-01-01 出版日期:2003-11-25 发布日期:2003-11-25

### PHOSPHATE UPTAKE CHARACTERISTICS OF KINETICS AND PHOSPHORUS EFFICIENCY IN CLONES OF POPLAR

Zhang Huanchao2,Wang Gaiping3,Xu Xizeng4,Xu Chengkai2,Hu Zhengyi5

1. College of Forest Resources and Environment, Nanjing Forestry University Nanjing210037;The Institute of Soil Science, Chinese Academy of Sciences Nanjing210008
• Received:2001-12-11 Revised:1900-01-01 Online:2003-11-25 Published:2003-11-25

Abstract: In order to explore the mechanism of interclonal differences of poplar in P efficiency and to find out a new way in breeding improved variety of poplar, phosphate uptake characteristics of kinetics and the relation between the kinetic characteristics and P efficiency were conducted by the method of solution culture with long term absorption by intact plants for poplar seedling in greenhouse. The results showed that the root uptakes of phosphate were obviously stronger in clone S17, S19, and 105, which were attested as high P efficiency, than in clone 106, 797, I-69, 1388, and 3244, which were low P efficiency clones. The values of Km, the Michaelis constant, which is the concentration where influx is half of Vmax, and Cmin, the critical concentration, the ion concentration in solution below which net influx of the ion ceases, of S17, S19, and 105 were much smaller than those of other five clones, respectively. This indicated that clones of high P efficiency were much stronger than those of low P efficiency in the affinity of root system to phosphate and in tolerating P deficiency. As a result of P deficiency stress such affinities were increased over 20% for the clones of high P efficiency but below 5% for the clones of low P efficiency, as indicated by the values of K m under two P treatments. Similarly, as showed by the values of Cmin, the tolerance to P deficiency stress was raised more than 85% for the clones of high P efficiency but less than 15% for the clones of low P efficiency. Consequently, variation in P uptake characteristic parameters of kinetics by root systems of various poplar clones was one of important mechanisms for the interclonal difference in P efficiency, and will probably be of great significance in breeding improved poplar variety in the future. Further more studies were needed to explain the difference of phosphorus efficiency by the index of Vmax.