Comparative analyses of leaf anatomy of dicotyledonous species in Tibetan and Inner Mongolian grasslands

Abstract

Knowledge of the leaf anatomy of grassland plants is crucial for understanding how these plants adapt to the environment. Tibetan alpine grasslands and Inner Mongolian temperate grasslands are two major grassland types in northern China. Tibetan alpine grasslands occur in high-altitude regions where the low temperatures limit plant growth. Inner Mongolian temperate grasslands are found in arid regions where moisture is the limiting factor. Few comparative studies concerning the leaf anatomy of grassland plants of the Tibetan Plateau and Inner Mongolian Plateau have been conducted. We examined leaf characteristics at 71 sites and among 65 species, across the alpine grasslands of the Tibetan Plateau and the temperate grasslands of the Inner Mongolian Plateau. We compared the leaf structures of plants with different life forms and taxonomies, and their adaptation to arid or cold environments. We explored relationships among leaf features and the effects of climatic factors (i.e., growing season temperature and precipitation) on leaf characteristics. Our results showed that (i) there were significant differences in leaf anatomy between Tibetan alpine and Inner Mongolian temperate grasslands. Except for mesophyll cell density, the values obtained for thickness of leaf tissue, surface area and volume of mesophyll cells were larger on the Tibetan Plateau than on the Inner Mongolian Plateau. (ii) Within the same family or genus, leaf anatomy showed significant differences between two regions, and trends were consistent with those of whole species. (iii) Leaf anatomy of woody and herbaceous plants also showed significant differences between the regions. Except for mesophyll cell density, the values obtained for the thickness of leaf tissue, and the surface area and volume of mesophyll cells were larger in herbaceous than in woody plants. (iv) Leaf anatomical traits changed accordingly. Total leaf thickness, thicknesses of lower and upper epidermal cells, and surface area and volume of mesophyll cells were positively correlated, while mesophyll cell density was negatively associated with those traits. (v) Growing season temperature had stronger effects on leaf anatomy than growing season precipitation. Although the communities in Tibetan and Inner Mongolian grasslands were similar in appearance, leaf anatomy differed; this was probably due to the combined effects of evolutionary adaptation of plants to environment and environmental stress induced by climatic factors.

Effects of grazing on ecosystem structure and function of alpine grasslands in Qinghai–Tibetan Plateau: a synthesis

“…, Ma et al. ). Therefore, these local environmental conditions such as altitude and MAT should be considered when making recommendations for management of grazing intensity.…”

“…The effect of grazing on aboveground vegetation growth was consistent between altitude and temperature, likely because temperature decreases with elevation in the QTP (K€ orner 2007, Liu et al 2009). In the QTP, temperature appears to be a key limiting factor for plant growth due to high altitude and low mean temperature (Kong et al 2012, Ma et al 2012. Therefore, these local environmental conditions such as altitude and MAT should be considered when making recommendations for management of grazing intensity.…”

Variation in leaf traits at different altitudes reflects the adaptive strategy of plants to environmental changes

“…Thicker leaves and epidermis can provide a greater buffer between inner leaf temperature and outer environmental temperature and keep higher internal temperature, which would contribute to maintaining normal physiological activity for plants under low temperatures at higher altitude. In addition, thicker leaves and leaf epidermises can reduce the damage inflicted by the high-level ultraviolet irradiation present at high altitudes (Ma et al, 2012). It can also facilitate greater water storage and is evolutionarily favorable for efficient water use and reducing transpiration (Guo et al, 2017).…”

Implications of polyploidy events on the phenotype, microstructure, and proteome of Paulownia australis

“…Leaf is highly responsive to environmental conditions, therefore, its microstructures may reflect the adaptability of plants to environmental conditions [42]. The olive Chemlali cultivar exhibited more tolerance to water stress than the Chétoui cultivar, and its palisade was thicker [43].…”