深圳福田土著和外来红树物种叶片的化学计量特征

Stoichiometric Characteristics of Leaves of Native and Alien Mangrove Species in Futian,Shenzhen

开展植物化学计量研究对认知植物的生态适应策略具有重要意义。以深圳市福田红树林国家级自然保护区中的土著物种白骨壤(Avicennia marina)、秋茄(Kandelia obovata)、桐花树(Aegiceras corniculatum)和外来物种无瓣海桑(Sonneratia apetala)、海桑(Sonneratia caseolaris)为研究对象,研究5种物种叶片的化学计量特征,分析5种物种叶片的化学计量特征与其性状的关系。研究结果表明,外来物种无瓣海桑叶片中的全碳含量显著大于土著物种秋茄,而与其他2种土著物种无显著差异;2种外来物种叶片中的全氮含量都显著大于土著物种桐花树和秋茄,而与土著物种白骨壤无显著差异;2种外来物种叶片中的全磷含量都显著小于土著物种白骨壤,而与土著物种桐花树无显著差异;2种外来物种叶片中的全钾含量都显著大于土著物种桐花树和秋茄,而与土著物种白骨壤无显著差异;2种外来物种叶片的碳钾比、氮钾比和磷钾比都小于3种土著物种;5种物种叶片中的全钾含量的变异系数大于全碳、全氮和全磷含量的变异系数,5种物种叶片的碳钾比、氮钾比和磷钾比的变异系数都较大,2种外来物种叶片碳钾比的变异系数都大于3种土著物种;土著物种桐花树叶片中的全氮含量与全磷含量、全磷含量与全钾含量之间存在异速生长关系,其异速生长指数分别为-1.82和-0.82;外来物种无瓣海桑叶片中的全氮含量与全磷含量之间存在异速生长关系,其异速生长指数为2.69;在5种物种中,除了土著物种秋茄生长受氮和磷元素的共同限制以外,其他4种物种的生长都受氮元素限制;5种物种叶片中营养元素含量的化学计量比之间大多数都显著相关,而且物种的功能性状能显著影响其营养元素含量的化学计量比,即叶片中的营养元素含量与其性状存在耦合关系。

Ecological stoichiometry provides an effective approach for analyzing the relationship between plants and environment,and it is of great significance for understanding plant ecological adaptation strategies.To evaluate leaf stoichiometry and analyze the relationship between leaf stoichiometry and traits for different mangrove species,the contents of total carbon,total nitrogen,total phosphorus and total potassium in the leaves of 3 native species(Avicennia marina,Aegiceras corniculatum and Kandelia obovata)and 2 alien species(Sonneratia apetala and Sonneratia caseolaris)in Futian Mangrove National Nature Reserve were measured.The results showed that mean content of total carbon in the leaf of Sonneratia apetala was significantly higher than that of Kandelia obovata,but not significantly different from those of other 2 native species.Mean contents of total nitrogen in the leaves of 2 alien species were significantly higher than those of Aegiceras corniculatum and Kandelia obovate,but not significantly different from Avicennia marina.Mean contents of total phosphorus in the leaves of 2 alien species were significantly lower than that of Avicennia marina,but not significantly different from Aegiceras corniculatum.Mean contents of total potassium in the leaves of 2 alien species were significantly higher than those of Aegiceras corniculatum and Kandelia obovate,but not significantly different from Avicennia marina.The carbon-potassium,nitrogen-potassium,and phosphorus-potassium ratios in the leaves of 2 alien species were smaller than those of 3 native species.The coefficient of variation of total potassium content in the leaf was larger than those of total carbon,total nitrogen,and total phosphorus contents in the leaves of 5 mangrove species,and there were larger coefficients of variation of carbon-potassium,nitrogen-potassium,and phosphorus-potassium ratios in the leaves.The coefficients of variation of carbon-potassium ratios in the leaves of 2 alien species were larger than those of 3 native species.The allometric relationships were observed between total nitrogen content and total phosphorus content,total phosphorus content and total potassium content in the leaves of Aegiceras corniculatum,with the values of allometric exponent index of-1.82 and-0.82,respectively.The value of allometric exponent index was 2.69 between total nitrogen content and total phosphorus content in the leaves of Sonneratia apetala.Notably,except for co-limitation by nitrogen and phosphorus in the leaves of Kandelia obovata,the growth of 4 mangrove species were primary nitrogen-limited.Additionally,significant relationships were found that among leaf stoichiometries,and functional traits of the species significantly influenced its stoichiometric ratios,indicating that there was a coupling relationship between contents of nutrition elements in the leaves and its traits.