三倍体毛白杨不同无性系叶片养分含量研究

对三倍体毛白杨不同无性系叶片养分含量研究表明， N和K元素含量随着生长季 节而迅 速降低;Ca元素含量随生长季节而逐渐积累增加。P元素浓度在春季时略低于夏季，在秋 季最低; Mg元素含量在所测定的3个季节中基本没有差异。两元素含量的变化规律有待于进一步的 研 究。大量营养元素的年均值含量的比值为N∶P∶K∶Ca∶Mg为1.00∶0.06∶0.40∶0.10∶ 0.04。微量元素Fe、Mn、Cu和Zn的含量均随生长季节而逐渐积累增加。不同无性系变化规律 相 似。方差分析表明，只有N含量差异显著（ F=6.73>F 0.05 =3.68，n =18）。不同季节不同无性系 的元素含量大小次序不相同。研究结果可为三倍体毛白杨养分管理提供依据。

Foliar Nutrient Contents in Different Clones of Triploid Populus tomento sa

Foliar nutrient contents in different clones of triploid Po pulus tomentosa were measured in2006. It was found that the contents of nitrogen and potassium decreased w ith time; While the content of calsuim always in the trend of increasing around the year. The content of p hosphorus in spring were lower than those of in summer， and lowest in autumn; the contents of magnesi um changed little in all three seasons. The causes of the variations of the elements needed to be furthe r investigated.According to the annual avˉ erage contents，the ratio of N:P:K:Ca:Mg was1.00:0.06:0.40:0.10:0.04.The contents of trace eleˉ ments，such as Fe， Mn，Cu，and Zn， increased with time. Different clo nes had the same dynamics. With the samples in July， the results of analysis of variance showed o nly N contents were significant at 5% level （F=6.73>F 0.05 =3.68，n=18）.Generally， the orders of nutrient contents in differe nt clones were not aˉ like in the seasons. The results may benefit the nutrient management of triploid P.tomentosa.