茂兰喀斯特森林常见钙生植物叶片元素含量及其化学计量学特征

喀斯特森林植物的生态适应性及其对环境变异的生态响应和调控机制是喀斯特森林生态系统稳定性维护和退化生态系统恢复重建必需明确的关键科学问题。为探讨喀斯特森林植物的生态适应性调控机制，本文以茂兰喀斯特森林几种常见钙生植物为研究对象，分别对其叶片10种必需元素进行了测定分析。结果表明：含量大于10000 mg·kg^-1的元素有N、K和Ca，1000～10000 mg·kg^-1的元素有P、Mg和S，100～1000 mg·kg^-1的元素有Fe和Mn，小于100 mg·kg^-1的元素有Zn和Ni。这些元素中，除 P 外均高于已报道的陆生高等植物所需元素的合适组织浓度，但仍全部处于世界陆生维管植物元素平均含量范围内。元素含量特点是w（Ca）＞w（K）＞w（Mg）型。P、Mg、Fe的频数分布呈正态分布，N、K、Ca、S、Mn、Zn、Ni呈对数正态分布。元素间的相关分析表明，N和S、P和Mg、K和S、Ca和Mg、Ca和Zn具有极显著正相关关系（P≤0.01）， Mg和Zn也具有显著正相关关系，而N和Fe、S和Fe具有显著负相关关系（P≤0.05）。根据植物叶片w（Ca＋Mg）含量，冷水花（Pilea notate）、荔波唇柱苣苔（Chirita liboensis）和掌叶木（Handeliodendron bodinieri）属于嗜钙型植物，石山吴茱萸（Evodia calcicola）属于喜钙型植物，黄梨木（Beniodendron minus）、单性木兰（Kmeria septentrionalis）、南天竹（Nandina domestica）、粗糠柴（Mallotus philippensis）、石山桂（Cinnamomum calcareum）和黔竹（Dendrocalamus tsiangii）属于随遇型植物，贵州悬竹（Ampelocalamus calcareous）属于厌钙型植物，荔波鹅耳枥（Carpinus lipoensis）、石山胡颓子（Elaeagnus calcarea）介于喜钙型植物和随遇型植物之间，石山楠（Phoebe calcarea）介于随遇型植物和厌钙型植物之间。对叶片元素化学计量比值的分析表明，喀斯特钙生植物具有低P、K和高Ca、Mg的特点，绝大部分植物属于P

Characteristics of Element Contents and Ecological Stoichiometry in Leaves of Common Calcicole Species in Maolan Karst Forest

Ecological adaptability mechanism of karst plants and their ecological response to environmental variation are essential for stability maintenance of karst forest ecosystem and restoration and reconstruction of degraded ecosystem. To investigate the＆amp;nbsp;ecological adaptability mechanism of plant in karst forest, the characteristics of 10 elements in plant leaves collected from Maolan Karst Forest were investigated. The results showed that the contents of N, K and Ca were greater than 10000 mg·kg^-1, those of P, Mg and S varied between 1000 and 10000 mg·kg^-1, those of Fe and Mn varied between 100 and 1000 mg·kg^-1, and those of Zn and Ni were lower than 100 mg·kg^-1. Except for element P, the contents of other elements were higher than those reported concentrations of the terrestrial higher plant required from the appropriate tissue, but all were within the scope of the average level of land vascular plants in the world. The element contents were characterized as“w（Ca）〉w（K）〉w（Mg）”type. The contents of elements P, Mg and Fe followed normal distribution, while the contents of elements N, K, Ca, S, Mn, Zn and Ni followed lognormal distribution. The correlations between N, S and P;Mg and K;S, Ca and Mg;Ca and Zn were statistically significant in different plant species （ P≤0.05 ）. According to the element contents of w（Ca ＋ Mg） in plant leaves, Pilea notate, Chirita liboensis and Handeliodendron bodinieri belonged to calciphile type plant, Evodia calcicola belonged to calciphilous plants, Beniodendron minus, Kmeria septentrionalis, Nandina domestica, Mallotus philippensis, Cinnamomum calcareum and Dendrocalamus tsiangii belonged to calcium-indifferent, Ampelocalamus calcareous belonged to calcifuges, while Carpinus lipoensis and Elaeagnus calcarea are between calciphilous plants and calcium-indifferent, Phoebe calcarea was between calcium-indifferent and calcifuges. The calcicole species were almost defined as P limited plants, and were characterized by lower content of P, K