The prospects for future applications in crop breeding are proposed. In addition to the damages, the acclimation processes to UV-B can be investigated. Presented results demonstrate that the rapid, non-invasive, chlorophyll fluorescence-based methods may provide valuable information on the actual functional state of photosynthetic apparatus related to the processes of light energy conversion in the chloroplast, including monitoring of the UV-sensitive sites of the photosynthetic system. The plant species and genotypes differ in responses and susceptibility to UV-B stress, highlighting the role and importance of acclimation processes and protective mechanisms, including creating the efficient UV screen in plant epidermis and dynamic regulation of photosynthetic processes toward efficient photoprotection. Results of numerous studies demonstrate the adverse effects of UV-B on different plant structures and components, including those essential for the photosynthetic processes. In addition to the regulatory role, the UV-B represents an important stress agent. The effects of UV-B radiation on photosynthesis and photosynthetic apparatus of higher plants are reviewed. Meiosis and cytomixis, performing the function of selection, play an important role in maintaining tissue and genetic homeostasis in the male reproductive system. Accordingly, the “genetic load” on the reproductive tissue can be removed more efficiently, since the defense/recovery mechanisms are activated. With an increase in UV radiation, the importance of cell selection grows its activation has a threshold character. UV causes genome instability, which can be one of the adaptation mechanisms. ![]() Depending on the dose, UV radiation can suppress or stimulate flowering, generative organ differentiation, activate cytomixis, and increase the pollen grain (PG) of “low plasma” with signs of autophagy. High exposure to UV-B negatively affects the trophic supply of plants. The flower is also exposed to indirect effects of ultraviolet radiation. However, pollen and the pollination process are vulnerable to UV radiation. The generative organs of angiosperms are effectively protected from UV-B by integumentary tissues, which accumulate phenolic components, absorb UV radiation, and trap reactive oxygen species. The activation of the general stress response is associated with the changes in gene expression. UV-B radiation has two main effects: the first is the response to induced damage, and the second is the perception by the UV-B receptor, which leads to UV-B-induced photomorphogenesis and adaptation. This work has been conducted to further investigate the response of plants to UV-B radiation as an integrating process of the interaction of the genome with environmental factors through signaling and regulatory mechanisms. The identification of key molecules involved in melatonin-NO signaling is important for the development of new strategies to reduce the effects of environmental stresses.įor decades, effect of ultraviolet radiation on plants and their sexual reproduction has been under focused attention of biological research globally. However, the molecular mechanisms underlying melatonin-NO cross-interactions in plant UV-B responses are still poorly understood. One of the mechanisms of the protective action of melatonin is the activity of trapping NO and peroxynitrite, as well as inhibiting the production of NO and the activity of NO synthase. ![]() The interactions between melatonin and nitric oxide occur through various intermediate biomolecules, namely phytohormones, phenolic compounds, antioxidant enzymes, ROS, and other metabolites. NO is also a signaling molecule that is involved in many physiological functions and, therefore, plays an important role in responses to various abiotic stresses. Melatonin, as a secondary messenger molecule and growth regulator, plays an important role in reducing the damaging effects of abiotic stress by neutralizing ROS, maintaining oxidative homeostasis in the cell, and regulating the activity of genes associated with stress response. In recent years, much attention has been paid to the study of melatonin functions, as well as melatonin-NO cross-talking in plant responses to stress.
0 Comments
Leave a Reply. |