海南滨海常见沙生植物叶片金属元素计量特征

Metrological Characteristics of Metal Elements in Leaves of Common Sandy Plants in Hainan Coastal Areas

摘要:

金属元素是植物生物过程中必需的，但又可能产生胁迫的物质，为探讨滨海沙生植物在高盐环境下对金属元素吸收利用特征，本研究以6种海南常见滨海沙生植物[单叶蔓荆(Vitex trifolia)、苦郞树(Volkameria inermis)、假马鞭(Stachytarpheta jamaicensis)、飞机草(Eupatorium odoratum)、马缨丹(Lantana camara)、厚藤(Ipomoea pes-caprae)]为研究对象，测定其叶片和土壤中的4种金属元素钾(K)、钙(Ca)、钠(Na)和镁(Mg)含量，分析元素富集系数、化学计量比及其相关性。结果表明, 滨海沙生植物叶片金属元素含量呈现K>Na>Ca>Mg的分布特征，含量分别为21.07、1.49、1.13和0.59 mg/g，具有显著的种间和区域差异，反映了植物对不同土壤条件和环境胁迫的适应性调节机制；植物对K和Na的吸收能力最强，而对Ca和Mg的吸收能力相对较弱；滨海沙生植物对金属元素K、Na富集作用最强；不同滨海沙生植物对不同金属元素的富集能力存在差异，其中单叶蔓荆、厚藤对K、Na、Mg元素富集能力表现最好，飞机草对Ca元素的富集能力表现最好；植物叶片K与土壤Na、Mg呈显著正相关，与土壤K、K:Na、K:Mg和Ca:Mg呈显著负相关；叶片Ca与土壤的K、K:Ca、K:Na和K:Mg呈显著正相关；叶片Na、Mg与土壤金属元素及其计量比无显著相关性，说明滨海沙生植物具有复杂的离子调控机制。这为全面系统揭示滨海沙地地区生态系统的养分状况和对滨海沙生植物的培育管理具有指导意义，还补充了滨海沙生植物金属元素板块内容。

Abstract:

Metal elements are essential for plant biological processes but may also cause stress. To explore the characteristics of metal element absorption and utilization by coastal halophytes under high-salt conditions, this study selected six common coastal halophytes in Hainan [Vitex trifolia, Volkameria inermis, Stachytarpheta jamaicensis, Eupatorium odoratum, Lantana camara, and Ipomoea pes-caprae] as research subjects. The contents of four metal elements, potassium (K), calcium (Ca), sodium (Na), and magnesium (Mg), in their leaves and soil were determined, and the enrichment coefficients, stoichiometric ratios, and their correlations were analyzed. The results showed that the metal element contents in the leaves of coastal halophytes were distributed as K>Na> Ca>Mg, with contents of 21.07, 1.49, 1.13, and 0.59 mg/g, respectively. There were significant interspecific and regional differences, reflecting the adaptive regulatory mechanisms of plants to different soil conditions and environmental stresses. The plants had the strongest absorption capacity for K and Na, while the absorption capacity for Ca and Mg was relatively weak. Coastal halophytes had the strongest enrichment effect on metal elements K and Na. Different coastal halophytes had different enrichment abilities for different metal elements. Among them, Vitex trifolia and Ipomoea pes-caprae had the best enrichment abilities for K, Na, and Mg, while Eupatorium odoratum had the best enrichment ability for Ca. The leaf K content was significantly positively correlated with soil Na and Mg, and significantly negatively correlated with soil K, K:Na, K:Mg, and Ca:Mg. Leaf Ca was significantly positively correlated with soil K, K:Ca, K:Na, and K:Mg. Leaf Na and Mg had no significant correlation with soil metal elements and their stoichiometric ratios, indicating that coastal halophytes have complex ion regulation mechanisms. This provides guidance for comprehensively and systematically revealing the nutrient status of the ecosystem in coastal sandy areas and the cultivation and management of coastal halophytes, and also supplements the content of metal elements in coastal halophytes.