Anatomical and morphological features of leaves of Rhodiola rosea L. in natural conditions of the mountains in Southern Siberia (Altai Mountains)

The study of natural coenopopulations of the rare medicinal species Rhodiola rosea is of highest relevance for conservation of this valuable plant species. Analysis of the adaptive response of the species growing under different environmental conditions is basically used to elaborate recommendations for its protection and rational use. The aim of this work was to study the anatomical and morphological features of the leaf blades of Rh. rosea growing under different environmental and coenotic conditions of the Altai Mountains. We studied the anatomical features of leaves of Rh. rosea from 7 coenopopulations (in one coenopopulation, both female and male plants were studied) and assessed the adaptive response of plants to different growing conditions by conventional methods. The values of indicators from different coenopopulations were compared by one-way analysis of variance (ANOVA), and the correlation coefficient was calculated to estimate the correlation between different indicators. The study revealed a reserve of adaptive plasticity for Rh. rosea, which allows the species to grow under different light and water conditions. For specimens from one geographic location studied, statistically significant differences in the indicator values were fewer compared with specimens from different areas. Heliophytic and xerophytic adaptations of the studied plants varied depending on coenopopulation. The analysis of male and female Rh. rosea species from the Kurai ridge (CP 3) revealed that the most photosynthetically active layer and vascular tissue are better developed in leaves of females compared to males. It was found that Rh. rosea growing in the mountains bear shorter and thicker leaves; the thickness of integumentary tissue with cuticle increases at higher altitudes, the number of stomata and cells on integumentary tissue per epidermis unit area decreases, and the thickness of photoassimilating tissue grows. Changes in anatomical and morphological characteristics are adaptive responses to increased insolation at higher altitudes and, probably, to decreased partial pressure of carbon dioxide.针对稀有药用物种红景天（Rhodiola rosea）的自然群落种群（coenopopulation）开展研究，对该珍贵植物物种的保护具有至关重要的意义。对生长于不同环境条件下的该物种的适应响应（adaptive response）进行分析，可为其保护与合理利用制定科学指导方案。本研究旨在探究阿尔泰山脉不同环境与群落条件下生长的红景天的叶片解剖与形态特征。本研究针对7个群落种群中的红景天叶片解剖特征展开分析，其中1个群落种群同时涵盖雌雄株样本，并采用常规方法评估了植物对不同生长条件的适应响应。采用单因素方差分析（one-way analysis of variance, ANOVA）对不同群落种群的指标数值进行比较，并通过计算相关系数来评估不同指标间的相关性。本研究揭示了红景天存在适应可塑性储备，使其能够在不同光照与水分条件下生长。相较于来自不同区域的样本，同一地理区域的研究样本其指标数值的统计学差异更为有限。研究对象的阳生（heliophytic）与旱生（xerophytic）适应特征因群落种群而异。对库赖岭（Kurai ridge，CP 3）的红景天雌雄株样本的分析显示，相较于雄株，雌株叶片的光合活性层与维管组织发育更为完善。研究发现，山地生长的红景天叶片更短更厚；随着海拔升高，带角质层（cuticle）的表皮组织（integumentary tissue）厚度增加，单位表皮面积内的气孔（stomata）与表皮细胞数量减少，而光合同化组织（photoassimilating tissue）厚度则有所增加。解剖与形态特征的这些变化，是红景天对高海拔地区增强的日照辐射（insolation），以及可能存在的二氧化碳分压（partial pressure of carbon dioxide）的适应响应。