Pollen Viability, and the Photosynthetic and Enzymatic Responses of Cowpea (Vigna unguiculata (L.) Walp., Fabaceae) in the Face of Rising Air Temperature: A Problem for Food Safety

Abstract

Rising temperature affects agricultural production, causing food insecurity. Thus, the objective of this study was to evaluate how increased temperature influences pollen viability, photosynthetic and enzymatic responses, and their consequences on the final yield of cowpea cultivars. The cultivars BRS Acauã, BRS Guariba, BRS Gurguéia, and BRS Pajeú were used, kept in growth chambers under two temperature regimes: 24.8–30.8–37.8 °C and 20–26–33 °C. The cultivars BRS Acauã, BRS Guariba, and BRS Pajeú showed prolonged flowering and greater flower abortion, at 23.58%, 34.71%, and 25.55%, respectively, under an increase of 4.8 °C in temperature. This increase also reduced the viability of BRS Acauã and BRS Pajeú pollen by 34 and 7%, respectively. Heating increased stomatal opening and transpiration but reduced chlorophyll content. The enzymatic response varied according to cultivars and temperature. Changes in photosynthetic and enzymatic activities contribute to reducing pollen viability and productivity. BRS Acauã was the most affected, with an 82% reduction in the number of seeds and a 70% reduction in production. BRS Gurguéia maintained its production, even with an increase of 4.8 °C, and can be selected as a cultivar with the potential to tolerate high temperatures as it maintained pollen viability, with less flower abortion, with the synchrony of physiological and biochemical responses and, consequently, greater production.

Unraveling the interplay of temperature, plant genotype, and plant-growth-promoting bacteria inoculation on cowpea nodulation with native soil bradyrhizobia

“…Several environmental factors, such as air temperature and the use of PGPB inoculants, can in uence cowpea growth. Actually, the temperature has been pointed out as the main element in uencing several aspects of cowpea biology, such as ower abortion, pollen viability, and plant growth (Barros et al 2021(Barros et al , 2022(Barros et al , 2024a. In addition to the literature reports on the temperature in uencing cowpea's aboveground development, the present study indicated that the air temperature is also important for belowground cowpea development and interaction with soil bacteria, affecting its nodulation with the established autochtonous rhizobial community.…”

“…The natural tolerance of this species to hash conditions can be boosted by agrotechnological improvements such as plant breeding, aiming for the development of resistant genotypes (Santos 2011), inoculation of selected rhizobia (Marinho et al 2014(Marinho et al , 2017de Andrade et al 2021), and plant-growth promoting bacteria (PGPB) (Galindo et al 2020;Kaschuk et al 2022). Recent reports have already shown that the temperature affects cowpea growth, biochemistry, and reproductive biology (Barros et al 2020(Barros et al , 2021(Barros et al , 2024a, so heat tolerance is essential in focusing on plant breeding to the future climatic reality. However, exploiting cowpea ecological partners, such as rhizobial microsymbionts or PGPB, could lead to faster results and boost the genetic improvement of cowpeas for plant development and yield under such harsh conditions.Cowpea nodulates with a wide range of soil rhizobia belonging to alpha-and beta-rhizobia clusters (de Castro et al 2017;Jaiswal and Dakora 2019).…”

Ecological stability, plasticity, and adaptability of cowpea varieties (Vigna unguiculata (L.) Walp. subsp. sesquipedalis (L.) Verdc.)

“…The study of the effect of temperature stress on pollen is extremely important, as the viability of pollen grains is one of the key indicators for assessing plant tolerance to temperature stress (Havryliuk et al, 2022). In San Francisco, the cowpea variety BRS Gurguéia has proven itself well, which under conditions of temperature stress maintained greater pollen viability with a lower level of flower abortivity and, as a result, provided a higher yield (Barros et al, 2024). Our research also confirms that high temperatures affected the metabolism of cowpea plants, causing changes in plant growth.…”

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“…The study of the effect of temperature stress on pollen is extremely important, as the viability of pollen grains is one of the key indicators for assessing plant tolerance to temperature stress (Havryliuk et al, 2022). In San Francisco, the cowpea variety BRS Gurguéia has proven itself well, which under conditions of temperature stress maintained greater pollen viability with a lower level of flower abortivity and, as a result, provided a higher yield (Barros et al, 2024). Our research also confirms that high temperatures affected the metabolism of cowpea plants, causing changes in plant growth.…”