桉树不同成熟度叶片水溶性营养元素循环规律

The Characteristics of Nutrient Elements Circulation in Eucalyptus Leaves with Different Maturity

[目的]探究桉树人工林不同成熟度叶片水溶性营养元素的变化规律及其与重吸收率之间的关系。[方法]选取广西小林镇桉树人工林作为研究对象,测定桉树幼嫩叶、成熟叶、衰老叶的氮(N)、磷(P)、钾(K)、镁(Mg)及其水溶性氮(WSN)、水溶性磷(WSP)、水溶性钾(WSK)、水溶性钙(WSCa)、水溶性镁(WSMg)、水溶性硼(WSB)营养元素,并对其含量进行相关性分析。[结果]幼嫩叶的N、P、K、Mg重吸收率均高于成熟叶的N、P、K、Mg重吸收率,且幼嫩叶与成熟叶的P、K重吸收率具有显著差异。WSN、WSP、WSK、WSMg的转移规律为衰老叶向成熟叶和幼嫩叶转移;WSB和WSCa随着叶片的生长发育而积累,Ca、B等植物养分由衰老叶向成熟叶和幼嫩叶转移与可溶程度没有必然联系。基于生态化学计量学分析,衰老叶WSB与WSN、WSP、WSK、WSMg、WSCa均呈负相关,幼嫩叶与衰老叶表现不一致。[结论]该研究可为桉树人工林的营养元素诊断及优化施肥方案提供科学依据。

[Objective]To explore the variation pattern of water-soluble nutrient elements of leaves from Eucalyptus stands of different maturity and the relationship between them and the rate of reabsorption.[Method]This study selected Eucalyptus plantation from Xiaolin Town,Guangxi,determine the levels of nitrogen(N),phosphorus(P),potassium(K),magnesium(Mg)and their water-soluble nutrients in juvenile,mature leaves and senescing leaves of Eucalyptus plantation,including nitrogen(WSN),phosphorus(WSP),potassium(WSK),calcium(WSCa),magnesium(WSMg),boron(WSB).[Result]The results showed that the N,P,K,and Mg reabsorption rates of juvenile leaves were higher than those of mature leaves and that the P and K reabsorption rates of juvenile and mature leaves were significantly different.The transfer of WSN,WSP,WSK and WSMg was regular for senescing leaves to mature and juvenile mature leaves;WSB and WSCa accumulated as the leaf grows and develops,and the transfer of plant nutrients such as Ca and B from senescent to living tissues was not necessarily linked to the extent to which this element was soluble.Based on ecochemometric analysis,WSB of senescing leaves was negatively correlated with WSN,WSP,WSK,WSMg,WSCa,while the appearance of juvenile leaves was inconsistent with senescing leaves.[Conclusion]This study can provide scientific basis for the diagnosis of nutrient elements in Eucalyptus plantation and the optimization of fertilization program.