Salt-Acclimation Physiological Mechanisms at the Vegetative Stage of Cowpea Genotypes in Soils from a Semiarid Region

Abstract

Developing salt-tolerant plants has emerged as a highly efficient approach to cope with salinity damage on crop growth and productivity. This study aimed to elucidate the mechanisms of salt acclimation in cowpea plants [Vigna unguiculata (L.) Walp] and screen salt-tolerant potential genotypes during the early vegetative stage. Seven cowpea genotypes (Epace, Juruá, Maratauã, Milagroso, Pitiúba, Sempre verde, and TVU) were irrigated for 24 days with saline solutions of electrical conductivity 0.8 (control), 4.0 (moderate stress), and 8.0 dS m −1 (severe stress). Growth, water status, membrane damage, and variables related to photosynthetic machinery efficiency were evaluated. Biomass accumulation dramatically decreased with salinity, and the reductions were intensified by increasing the salt level. Nevertheless, under moderate salinity, Pitiúba plants showed less reductions in growth than other genotypes. Under moderate stress, Pitiúba plants exhibited maintenance of osmotic potential and photosynthetic pigments, which was consistent with unaltered membrane and elevated leaf succulence, resulting in improved photochemical performance. Conversely, although TVU, Juruá, and Milagroso plants had activated responses against moderate salinity, including reduced leaf osmotic potential and improved stomatal conductance, these responses were not sufficient to mitigate salt injury. The findings clearly show that the Pitiúba genotype activates coordinated responses to mitigate moderate salt damage, constituting an alternative for cultivating cowpea plants in saline environments.

Silicon alleviates drought damage by increasing antioxidant and photosynthetic performance in cowpea

“…The plant material was dried in an oven with forced air circulation at 65°C and, at the end, used to estimate the dry mass of the aerial part (MSPA) and roots (MSR). The relative tolerance to drought was obtained through the ratio between the MSPA of the plants subjected to drought in relation to the MSPA of the well‐irrigated plants (Miranda et al, 2021).…”

Photosynthetic machinery efficiency and water status are determinant for performance of semiarid-adapted cotton cultivars (Gossypium hirsutum L.) under drought

“…Subsequently, after reaching a constant mass, dry mass was determined using a precision balance. The relative stress tolerance index was calculated considering the total dry mass of stressed plants compared to the dry mass of control plants, following adaptations of the methodology by Miranda et al (2021) and Silva et al (2023).…”

Selection of Soybean and Cowpea Cultivars with Superior Performance under Drought Using Growth and Biochemical Aspects

“…Subsequently, the plant material was immediately frozen and lyophilized to measure the dry mass. The index of relative tolerance to drought (RToler) was calculated by comparing the total dry mass of drought-stressed plants to the total dry mass of control plants [44]. Specifically, the total dry mass of plants grown under 60% FC for soybean and 75% FC for cowpea were used as controls for calculating the Rtoler index.…”