滨海沙地人工林树种水分利用效率和叶片养分浓度比较及其关系分析

Comparison and Relationship Analysis of Water Use Efficiency and Foliar Nutrient Concentrations in Different Tree Species of Southeast Coastal Area

以福建省福州市滨海后沿沙地人工营造的湿地松、木麻黄、尾巨桉、肯氏相思和纹荚相思人工林为研究对象,运用稳定碳同位素法测定植物水分利用效率,探索叶片氮、磷养分状况与水分利用效率之间的差异及相互关系。结果表明:(1)湿地松和肯氏相思的叶片δ13 C均与尾巨桉差异显著(P<0.05),但湿地松、木麻黄、肯氏相思、纹荚相思之间的叶片δ13 C均无显著差异;肯氏相思、纹荚相思的叶片δ15 N均显著高于湿地松、木麻黄和尾巨桉。(2)不同树种水分利用效率大小依次为:湿地松>肯氏相思>木麻黄>纹荚相思>尾巨桉,且湿地松叶片的WUE显著高于尾巨桉36.87%,而与其他树种的水分利用效率均无显著差异。(3)各树种叶片氮浓度大小依次为:肯氏相思>纹荚相思>尾巨桉>木麻黄>湿地松,但仅肯氏相思和纹荚相思与湿地松之间差异达到显著水平;各树种叶片磷浓度大小依次为:尾巨桉>肯氏相思>纹荚相思>湿地松>木麻黄,其中尾巨桉与湿地松、木麻黄、纹荚相思之间差异显著;木麻黄和纹荚相思人工林叶片的N/P显著高于尾巨桉人工林,其余树种之间的叶片N/P均无显著差异。(4)叶片δ13 C与叶片N浓度呈显著二次曲线相关关系,叶片δ15 N与叶片N浓度呈极显著线性正相关关系(P<0.01)。研究发现,滨海沙地不同树种人工林间水分利用效率、叶片氮浓度、磷浓度、N/P均存在显著差异,水分利用效率与叶片氮浓度、磷浓度均呈显著负相关关系,氮、磷含量是影响滨海沙地沿海防护林树种水分利用效率的重要因子。

We studied Pinus elliottii,Casuarina equisetifolia,Eucalyptus urophylla×E.grandis,Acacia cunninghamia and A.aulacocarpa plantations in the coastal sandy land of Fuzhou City,measured their water use efficiency by stable carbon isotope method,and explored water use efficiency(WUE),nitrogen(N)and phosphorus(P)status of foliar as well as their relationships.The results showed that:(1)There were significant differences in foliarδ13 C between P.elliottii and E.urophylla×E.grandis,A.cunninghamia and E.urophylla×E.grandis(P<0.05).However,there was no significant difference in foliarδ13 C among P.elliottii,C.equisetifolia,A.cunninghamia and A.aulacocarpa.The foliarδ15 N of A.cunninghamia and A.aulacocarpa were significantly higher than those of P.elliottii,C.equisetifolia and E.urophylla×E.grandis.(2)WUE varied with different tree species in the order of P.elliottii>A.cunninghamia>C.equisetifolia>A.aulacocarpa>E.urophylla×E.grandis.The WUE of foliar of P.elliottii was significantly higher than that of E.urophylla×E.grandis 36.87%,but there was no significant difference in water use efficiency between P.elliottii and other species.(3)The foliar N concentration of each species in turn was A.cunninghamia>A.aulacocarpa>E.urophylla×E.grandis>C.equisetifolia>P.elliottii.There was a significant difference between A.cunninghamia and P.elliottii,A.aulacocarpa and P.elliottii.The foliar P concentration of each species in turn was E.urophylla×E.grandis>A.cunninghamia>A.aulacocarpa>P.elliottii>C.equisetifolia.There was a significant difference between E.urophylla×E.grandis and P.elliottii,E.urophylla×E.grandis and C.equisetifolia,E.urophylla×E.grandis and A.aulacocarpa.The foliar N/P of C.equisetifolia and A.aulacocarpa was significantly higher than that of E.urophylla×E.grandis.There was no significant difference in foliar N/P among the other tree species.(4)The foliarδ13 C showed a significant second-degree parabola correlation with the foliar N concentration.The foliarδ15 N was extremely significantly positively correlated with the foliar N concentration(P<0.01).The study found that there was a significant difference among WUE,foliar N concentration,foliar P concentration,and N/P.In addition,WUE had significantly negative correlation with foliar N concentration and foliar P concentration.The foliar N and foliar P concentration would be key factors affecting WUE in coastal shelterbelt tree species in coastal sandy land.