ROS Homeostasis and Antioxidants in the Halophytic Plants and Seeds

Abstract

Reactive oxygen species (ROS) are excited or partially reduced forms of atmospheric oxygen, which are continuously produced during aerobic metabolism like many physiochemical processes operating throughout seed life. Previously, it was believed that ROS are merely cytotoxic molecules, however, now it has been established that they perform numerous beneficial functions in plants including many critical roles in seed physiology. ROS facilitate seed germination via cell wall loosening, endosperm weakening, signaling, and decreasing abscisic acid (ABA) levels. Most of the existing knowledge about ROS homeostasis and functions is based on the seeds of common plants or model ones. There is little information about the role of ROS in the germination process of halophyte seeds. There are several definitions for halophytic plants, however, we believed “halophytes are plants that can grow in very saline environment and complete their life cycle by adopting various phenological, morphological and physiological mechanisms at canopy, plant, organelle and molecular scales”. Furthermore, mechanisms underlying ROS functions such as downstream targets, cross-talk with other molecules, and alternative routes are still obscure. The primary objective of this review is to decipher the mechanisms of ROS homeostasis in halophytes and dry seeds, as well as ROS flux in germinating seeds of halophytes.

Nanoparticles as a Tool for Alleviating Plant Stress: Mechanisms, Implications, and Challenges

“…The non-enzymatic antioxidants include ascorbic acid (AA), α-tocopherol, carotenoids, flavonoids, glutathione (GSH), and plastoquinone/ubiquinone [ 25 , 26 , 27 ]. Both groups of antioxidants are necessary for ROS homeostasis, and previous studies suggest that high antioxidative activity is linked to stress tolerance in plants and thus plays a pivotal role in adaptation to stress in plants [ 28 , 29 , 30 ].…”

“…The non-enzymatic antioxidants include ascorbic acid (AA), α-tocopherol, carotenoids, flavonoids, glutathione (GSH), and plastoquinone/ubiquinone [25][26][27]. Both groups of antioxidants are necessary for ROS homeostasis, and previous studies suggest that high antioxidative activity is linked to stress tolerance in plants and thus plays a pivotal role in adaptation to stress in plants [28][29][30]. In recent years, the advancement in nanotechnology has been observed to be aligned with the study of nanoparticles in plants, as it can trigger the various enzymatic and nonenzymatic antioxidant capabilities of plants.…”