Abiotic Stress Responses in Woody Plants: Morphological, Physiological, and Anatomical Features

Abstract

Abiotic stressors may have intricate and varied impacts on the growth and development of forest trees. This article provides a comprehensive summary of the effects of abiotic stressors, such as flood, drought, severe temperature, salt, heavy metal, combination stresses, and microplastics, on the morphological, physiological, and anatomical features of woody plants. The focus is particularly on evaluating these effects from the viewpoint of the xylem. During abiotic stress, the ability of xylem to transport water declines, which is linked to the control of leaf stomata and the suppression of aquaporin (AQP) function. Concurrently, woody plants maintain control over the dimensions and structure of their roots and leaves in order to achieve a harmonious equilibrium between water intake and evaporation. The anatomical characteristics are modified as well, including increased density of leaf stomata, smaller conduits, and thicker cell walls. Furthermore, various types of stressors elicit distinct responses in plants. For instance, flooding leads to the development of adventitious roots and aeration tissues, while forest fires cause irreparable damage to the xylem. Low temperatures result in tissue freezing, salt stress hinders ion absorption, and exposure to heavy metals induces biological toxicity. Woody plants' growth may be periodically enhanced in conditions of drought, floods, and exposure to heavy metals. The impact of combined stress on the physiological, morphological, and anatomical characteristics of woody plants is not only cumulative. The underlying mechanism behind this phenomenon requires additional investigation, particularly in natural or near-natural environments.