Carbon is considered the main element and essential nutrient elements that make up the dry matter in the plant, which determines the morphogenesis of plants and the nutrients acquisition capacity. The foliar carbon content of plant can reflect the ability of plant's carbon assimilation and adapt to harsh environmental conditions. This study divided the saline-alkali sites into 3 degrees with relatively mild, moderate and severe saline-alkali based on the soil hardening degree, severity of soil salt efflorescence and growth condition of Tamarix chinensis L., mainly investigated the foliar total organic carbon (TOC) of T. chinensis Lour., nutrient elements contents including total N(TN), total P(TP), total K(TK), Na, Mg, Cu, Zn, Fe, Ca both in leaves and surface soil, and the cation exchange capacity of soil (CEC), to characterized TOC and nutrient contents in leaves of T. chinensis by contents of nutrient elements per unit mass (CEM) and contents of nutrient elements per unit area (CEA), to explore the relationship between the foliar total organic carbon and the nutrient contents both in leaves and soil. The results showed as follows, (1) There was no significant difference on pH value among the 3 degrees of saline-alkali sites, significant differences were found among 3 levels of saline-alkali sites of Na contents, the maximum value was on severe saline-alkali site (1462.51 mg·kg-1), and minimum value was on mild saline-alkali site (436.67 mg·kg-1), the salt stress of high content of Na+ might be the main environmental factors affecting the growth of T. chinensis plantation in North Shanxi. (2) Based on CEM and CEA values, TOC had the maximum value on moderate saline-alkali site (40.47 kg·kg-1 and 1.79 kg·m-2, respectively), Na content had the maximum value also on moderate saline-alkali site (2.76 kg·kg-1 and 0.12 kg·m-2, respectively), TN (1.95 kg·kg-1) and TP (0.27 kg·kg-1) based on CEM had the maximum value on mild saline-alkali site, TK (0.70 kg·kg-1) based on CEM had the maximum value on moderate saline-alkali site, showed that T. chinensis' growth was closely related to the nutrient elements, Na could be enriched in T. chinensis but not unlimited, there was a "enrichment threshold". (3) TOC had significantly positive correlation with K and Fe elements in T. chinensis leaves (P<0.05), and also had closely associated with K content of surface soil, which indicated that these two elements especially K elements played important role on leaf morphogenesis, nutritious composition and salt-alkali resistance of T. chinensis in Saline-alkali soil in North Shanxi.%根据土壤板结程度、地表返盐现象严重程度以及植物生长状况,将晋北干旱区盐碱地划分为相对轻度、中度、重度3个盐碱胁迫等级.以30年生柽柳(Tamarix chinensis Lour.)人工纯林植株为研究对象,通过对不同盐碱胁迫柽柳叶片总有机碳(TOC)以及叶片和0~15 cm表层土壤全N、全P、全K、Na、Mg、Cu、Zn、Fe、Ca等营养元素及土壤CEC含量进行测定,研究晋北干旱区盐碱地柽柳植株体内元素化学计量特征,探讨晋北干旱区盐碱地柽柳叶片和表层土壤营养元素与柽柳叶碳的相关性,探究其叶碳含量的主要限制性营养元素,分析影响柽柳叶碳即植物生长的关键性因素.研究结果表明,(1)pH值在3个等级盐碱胁迫土壤之间无显著差异;Na含量以重度盐碱地最高(1462.51 mg·kg-1),轻度盐碱地最低(436.67 mg·kg-1),差异显著,Na+含量相差较大导致的盐胁迫是影响柽柳人工林生长的主要环境因子.(2)基于单位质量和单位面积叶TOC含量均以中度盐碱地最高(分别为40.47 kg·kg-1和1.79 kg·m-2),Na含量(2.76 kg·kg-1和0.12 kg·m-2)以中度盐碱地最高;基于单位质量的TN(1.95 kg·kg-1)和TP(0.27 kg·kg-1)含量以轻度盐碱地最高,TK含量(0.70 kg·kg-1)以中度盐碱地最高,说明柽柳的生长与体内营养元素密切相关,Na能够在泌盐植物柽柳体内富集,但并不是无限富集,而是存在一个阈值.(3)柽柳叶TOC含量和叶片K、Fe含量呈显著正相关(P<0.05),与表层土壤K含量亦呈显著正相关(P<0.05),表明这两种元素尤其是K在晋北干旱区盐碱地柽柳叶片形态建成、养分吸收和抗盐碱方面具有重要作用.研究结果可为该地区植被恢复和生态环境改善提供科学依据.
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