福建漳江口3种红树植物叶与小枝化学计量特征及其影响因素

Chemical Stoichiometric Characteristics and Its Influencing Factors of Leaves and Twigs in Three Mangrove Plants in Zhangjiang River Estuary, Fujian Province

摘要:

为揭示红树植物叶和小枝的化学计量特征及影响因素，对福建漳江口3种红树植物[秋茄树(Kandelia obovata)、海榄雌(Avicennia marina)和蜡烛果(Aegeras corniculatum)]当年生叶片和小枝的碳(C)、氮(N)、磷(P)含量与化学计量比进行测定, 并分析其与叶表型特征、基径的相关性。结果表明，3种红树植物叶片C、N、P含量均值分别为421.91、18.05、1.79 g/kg, 小枝分别为439.28、9.70、1.58 g/kg，各器官养分含量在种间差异显著。该区域红树林N:P比值低于阈值，表明该地区红树林生态系统存在N限制特点。相关性分析表明，各树种器官元素分配及叶表型性状存在显著相关性，体现了红树植物的养分获取策略。叶和小枝的C:N、C:P与基径呈显著负相关，小枝N:P与基径呈极显著正相关，说明不同大小个体资源分配存在动态变化。器官、物种、叶表型性状、基径大小与红树物种化学计量特征均存在一定的相关性。因此认为3种红树物种的化学计量特征受到植物种类、器官类型、叶片养分获取策略、个体生长状况共同作用，并体现在营养物质分配方式及性状特征上。

Abstract:

To reveal the stoichiometric characteristics and influencing factors of leaves and twigs of mangrove plants, the contents of carbon (C), nitrogen (N), and phosphorus (P) and the stoichiometric ratios of current-year leaves and twigs of three mangrove species (Kandelia obovata, Avicennia marina, and Aegiceras corniculatum) in Zhangjiang River estuary, Fujian Province, were determined, and their correlations with leaf phenotypic traits and basal diameter were analyzed. The results showed that the mean contents of C, N, and P in leaves of the three mangrove species were 421.91, 18.05 and 1.79 g/kg, respectively, and those in twigs were 439.28, 9.70 and 1.58 g/kg, respectively. There were significant differences in nutrient contents in organs among different species. The N:P ratio of the mangrove ecosystem in this area was lower than the threshold, indicating that the ecosystem was N-limited. There were significant correlations between the element allocation of organs and leaf phenotypic traits of each tree species, reflecting the nutrient acquisition strategies of mangrove plants. The C:N and C:P of leaves and twigs were significantly negatively correlated with basal diameter, while the N:P of twigs was significantly positively correlated with basal diameter, indicating that the resource allocation of different-sized individuals changed dynamically. There were certain correlations between organs, species, leaf phenotypic traits, basal diameter, and the stoichiometric characteristics of mangrove species. Therefore, it was suggested that the stoichiometric characteristics of the three mangrove species were jointly affected by species, organ type, leaf nutrient acquisition strategy, and individual growth status, and were reflected in the nutrient allocation patterns and phenotypic traits.