狗尾草叶片N、P、K养分重吸收与化学计量比的偶联关系

Coupling relationship between nutrient resorption and stoichiometric ratios of N,P,and K in Setaria viridis(L.)Beauv.leaves

为探究狗尾草(Setaria viridis (L.) Beauv.)对砂质海岸恶劣环境的适应性,本文以烟台沿海防护林自然保护区核心区内黑松防护林下的狗尾草为研究对象,测定狗尾草成熟叶和衰老叶碳(C)、氮(N)、磷(P)、钾(K)元素的含量,分析其生态化学计量特征和养分重吸收特征,进而研究两者之间的偶联关系。结果显示,狗尾草叶片N∶P> 16,狗尾草生长发育更多受到P元素限制。叶片氮重吸收率(NRE)、磷重吸收率(PRE)、钾重吸收率(KRE)分别为(58.038±2.973)%、(62.167±5.301)%、(86.557±0.950)%,NRE、PRE均高于我国植物叶片平均重吸收率,KRE高于全球植物平均重吸收率。叶片化学计量特征与PRE相关性较强,与NRE和KRE相关性稍差,狗尾草叶片养分重吸收率主要受衰老叶化学计量比的影响。研究区内狗尾草重吸收率较高,其化学计量比与养分重吸收存在一定相关性,说明狗尾草适应性极强,能够很好地适应贫瘠的环境,对海岸带防护林的养护有重要意义。

We explored the adaptation of Setaria viridis(L.)Beauv.to harsh sandy coastal environments in the core area of the Yantai Coastal Shelter Forest Nature Reserve by measuring the carbon(C),nitrogen(N),phosphorus(P),and potassium(K)content in mature and senescent leaves,analyzing their ecological stoichiometric characteristics and nutrient resorption efficiencies,and studying the coupling relationship between the two.Results showed that leaf N∶P was greater than 16 and the growth and development of S.viridis was more restricted by P.Leaf nitrogen resorption efficiency(NRE),phosphorus resorption efficiency(PRE),and potassium resorption efficiency(KRE)were(58.038±2.973)%,(62.167±5.301)%,and(86.557±0.950)%,respectively.NRE and PRE were higher than the average plant leaf resorption efficiency in China and KRE was higher than the global average plant resorption efficiency.The leaf stoichiometric characteristics were strongly correlated with PRE,but slightly less correlated with NRE and KRE.Nutrient resorption efficiency of the leaves was mainly affected by the stoichiometric ratio of the senescent leaves.The nutrient resorption efficiency of S.viridis was high in the study area,with a certain correlation between the stoichiometric ratio and nutrient resorption.These results indicate that S.viridis exhibits strong adaptability to the barren environment,which is of great significance to the conservation of coastal protection forests.