Abstract:

【Objective】 To discuss(Populus euphratica) the adaptation characteristics of the saline environment and reveal the physiological mechanism of salt tolerance. 【Methods】 P. euphratica leaves in different saline habitats were used as experimental test materials, the ions were determined by boiling water extraction and boiling method, and the anatomical structure of the leaves was observed under light microscope by paraffin sectioning method, and the content of each ion of the leaves and the comparative anatomical structure characteristics of the leaves were studied. 【Results】 (1) In the low-salt environment, the fence tissue in the leaf of P. euphraticawas larger, the leaf thickness, sponge tissue and midvein vascular bundle area were the largest, and the sponge tissue thickness was significantly different compared with other environments. In the medium salt environment, the thickness of the upper and lower epidermis, the area of fence tissue and mucus cells were greater than those of other environments. In a high-salt environment, P. euphratica leaves increased the thickness of epidermis, sponge tissue and leaf thickness. (2) From low salt environment to high salt environment, the contents of Na⁺, Mg²⁺, Ca²⁺, ${\mathrm{H}\mathrm{C}\mathrm{O}}_3{}^{-}$ and Cl^- in poplar leaves decreased, and the K⁺ content in leaves increased, thus the ion balance in leaves being maintained. (3) Fence tissue, mucus cell area, fence tissue/sponge tissue, and leaf compactness were significantly or very positively correlated with ${\mathrm{H}\mathrm{C}\mathrm{O}}_3{}^{-}$ and Na⁺, and significantly or very negatively correlated with K⁺;K⁺ in leaves was susceptible to environmental influences, which was significantly correlated with soil pH, total salt and conductivity. The epidermal thickness, mucus cell volume, and grid-to-sea ratio on the leaves were strongly correlated with soil salinity and water content, indicating that when stressed by salinity, they would resist the stress environment by changing their own structure. 【Conclusion】 Under different saline environmental conditions, the leaves of P. euphratica chinensis are mainly regulated and stored in the leaves by salt separators and act on all parts of the leaves, so as to ensure the normal physiological metabolism of the tree body and form different leaf anatomical characteristics to adapt to the environment.

Key words: saline environment; Populus euphratica; ion; leaf anatomical structure

摘要：

【目的】研究胡杨 (Populus euphratica )对盐渍环境的适应特点,揭示其耐盐生理机制。【方法】以不同盐渍生境中的胡杨叶片为试材,采用沸水水提法与消煮法测定离子含量,采用石蜡切片法在光学显微镜观察叶片的解剖结构,分析叶片各离子含量及比较解剖结构特征。【结果】(1)在低盐生境中,胡杨叶片中栅栏组织较大,叶片厚度、海绵组织、中脉维管束面积最大,且海绵组织厚度与其他环境中相比差异显著;中盐生境中,上、下表皮厚度、栅栏组织及粘液细胞面积均大于其他环境;高盐生境中,胡杨叶片增加下表皮厚度、海绵组织的厚度及叶片厚度;(2)从低盐环境到高盐环境,胡杨叶片中Na⁺、Mg²⁺、Ca²⁺、${\mathrm{H}\mathrm{C}\mathrm{O}}_3{}^{-}$和Cl^-含量均减少,叶片中K⁺含量增加,叶片中离子平衡得以维持;(3)栅栏组织、粘液细胞面积、栅栏组织/海绵组织、叶片紧密度与${\mathrm{H}\mathrm{C}\mathrm{O}}_3{}^{-}$和Na⁺含量呈显著或极显著正相关,与K⁺含量呈显著或极显著负相关。叶片中K⁺含量易受环境影响,与土壤pH值、全盐、电导率均呈极显著相关;叶片上下表皮厚度、粘液细胞体积、栅海比等与土壤盐分和含水量相关性较强,受到盐分胁迫时通过改变其自身结构抵御胁迫环境。【结论】在不同的盐渍环境条件下,胡杨叶片主要通过盐分离子在叶片中的调控储存并作用于叶片各部位,保证树体正常生理代谢,并形成不同的叶片解剖结构特征以适应环境。

关键词: 盐渍环境, 胡杨, 离子, 叶片解剖结构