The Physiological Mechanism of Melatonin Enhancing the Tolerance of Oat Seedlings under Saline–Alkali Stress

Abstract

Exogenous melatonin (MT) regulates plant growth and mitigates stress in response to stress. To analyze the machinery of exogenous melatonin, which improves salt and alkaline tolerance in oats, MT’s function was identified in the oat seed germination stage in our previous study. In this study, morphogenesis, photosynthetic physiology, hormone levels, and ion homeostasis were evaluated using the same MT treatment concentration. The results revealed that compared to the S45 treatment, the 100 μmol·L−1 MT treatment efficiently increased the seedling height and main root length of oat seedlings; promoted secondary root development; enhanced the root volume and root surface area; maintained a higher photosynthetic pigment content (carotenoids; chlorophyll a; chlorophyll b); raised the leaf photosynthetic rate (Pn), intercellular CO2 concentration (Ci), conductance to H2O (Gs), and transpiration rate (Tr); enhanced the light energy absorption and conversion of leaves; increased the leaf GA3, Tryptamine (TAM), and IAA contents; and decreased ABA levels. Hierarchical cluster analysis revealed that MT treatment also increased the contents of P, K, Ca, Mn, Cu, Mg, Fe, Zn, Mo, Cd, Al, Se, Ni, Co, and Ti; decreased the Na/K ratio; and maintained cellular ionic homeostasis in oat seedlings under saline–alkali stress, as compared with the untreated group. These findings showed that MT treatment enhanced the adaptation of oat to saline–alkali stress through regulating the physiological process of seedling growth. This suggests that MT plays a different role in improving saline–alkali tolerance in the germination and seedling stages of oat.

Exogenous melatonin delays leaves senescence and enhances saline and alkaline stress tolerance in grape seedlings

“… 43 When plants are subjected to adversity stress, the plant body’s own antioxidant mechanism is disrupted, resulting in the accumulation of large amounts of reactive oxygen species (ROS), which leads to changes in the permeability of the cell membrane. 44 After the cell membrane is disrupted, excessive accumulation of ROS leads to an increase in MDA content. We found that: the MDA content of leaves were decreased continuously under saline and alkaline stress, while in roots were not synchronized with leaves changes.…”

Comparative analysis of the insecticidal activity against Sitophilus oryzae (L.) and agro-morphological characteristics of maize using non-biogenic and biogenic ZnO nanoparticles

“…Further, they offer the capacity to manage insect pest management activity against storage and crop pests through various mechanisms, including physical distortion, diminished fertility, decreased egg deposition, and repellent activity. [10][11][12] During seed storage, it is essential to protect seeds in storage from storage insect pests and enhance their viability. With this in mind, the aim of the present study was to perform a comparative analysis of the insecticidal value and agro-morphological characteristics of maize from seeds treated using nonbiogenic and biogenic ZnO nanoparticles.…”