Morpho-Physiological and Anatomical Alterations of Salt-Affected Thompson Seedless Grapevine (Vitis vinifera L.) to Brassinolide Spraying

Abstract

Salinity is one of the most critical crises worldwide that ultimately compromises future food security. Brassinosteroids including brassinolide (BL) are a class of polyhydroxy steroids phytohormones, that play a crucial role in several plant metabolic pathways and boost plants’ stress tolerance, but less data is accessible on its function in salt-affected grapevine. The experiment was conducted throughout the 2019 and 2020 experimental seasons at EL-Baramon experimental farm, Horticulture Research Institute, Mansoura, Egypt, to recognize the remediation potential of BL (1 and 2 mg L−1) in lightening salinity (NaCl at 1000, 2000, and 3000 mg L−1) injury on Thompson seedless grapevine seedlings (H4 strain) growth and physio-anatomical attributes. Data advocated that while salinity reduced growth attributes, BL applications substantially improved the overall salt-affected plant performance. Salinity stress significantly decreased photosynthetic pigment, relative water content, and ions percentage (nitrogen, phosphorus, potassium, potassium/sodium ratio). Alternatively, BL spraying significantly (p ≤ 0.05) increased the photosynthetic pigment, maintaining a favorable potassium/sodium ratio and increasing the ions percentage. Additionally, increasing salinity levels significantly boost plant sodium percentage and induce a membrane malfunction associated with increased membrane permeability; conversely, the application of BL decreased the sodium percentage associated with decreasing membrane permeability relative to non-treated salinized plants. Moreover, salinity and/or BL significantly improved the antioxidant capacity associated with rising proline accumulation and antioxidant enzyme activities. Anatomically, salinity stress considerably modified leaf structure; meanwhile, the spraying with BL drastically mitigates the harmful effects of salinity on leaf anatomy. Additionally, salt-affected plant cells explained various obvious organelles ultrastructural modifications and cellular damage; meanwhile, BL spraying to salt-affected plants repealed the ultrastructural modifications of cell organelles. Taken together, BL, especially 2 mg L−1, has a great potential to boost the salt tolerance of Thompson seedless grapevine seedlings (H4 strain). It improves salt tolerance by sustaining higher photosynthetic pigment concentrations, maintaining ion homeostasis, regulating water status, and stimulating antioxidant capacity as well as maintaining leaf anatomical attributes.

Enhancing Leaf Nutrient Levels in Polyembryonic Mango (Mangifera indica L.) Seedlings: The Impact of Saline Water Irrigation and 28-Homobrassinolide Spray

“…Miao et al (2007) proved that BRs application improved root nodulation capacity and nitrogenase activity, resulting in increasing N % in plant tissues. The results are in accordance with results obtained for grape [12].…”

“…Brassinolide was more effective in increasing ion percentage of N, P and K and decreasing Na + percentage. The K + /Na + ratio significantly decreased with salinity but conversely BL spraying improved the K + /Na + ratio in leaves at 2 mg l −1 [12].…”

“…Lower nitrogen content (1.05) was noticed in treatment combination S4H1 during first year at 9 MAS. It is reported by El-Banna et al [12] that nutrient concentrations except Na + drastically reduced under salinity conditions; however, BL application mitigated salinity injuries and concentration of Na + reduced whereas N, P and K increased in grapevine seedlings. The outcomes were compatible with Hatami and Pourakbar [13] in grape for salinity and Karlidag et al [14] in strawberry for brassinolide.…”

“…Growth promotive effect of BRs might have also been due to its role in ion homeostasis, which is necessary for various biochemical or physiological processes controlling growth [14]. The K + /Na + ratio significantly decrease with salinity, but BL spraying at 2 mg l −1 improved the K + /Na + ratio in leaves of grape [12].…”

Rootstocks for Grapevines Now and into the Future: Selection of Rootstocks Based on Drought Tolerance, Soil Nutrient Availability, and Soil pH

“…Grapevine leaves are unable to maintain high osmotic potential when exposed to extreme saline stress induced by drought, resulting in reduction in leaf water content and increase in the production of active O 2 species (AOS) including superoxide, hydrogen peroxides, and hydroxyl radicals [53,54]. Tis can further infuence leaf cell function of grapevine, resulting in decreased cell division and attenuated cell expansion and eventually declined plant growth [55,56]. Plants have developed an osmotic adjustment system to maintain water absorption from soil to root in response to water defciency, through the accumulation of organic osmolytes such as sugars and quaternary ammonium compounds [54].…”