Germination and Initial Growth of Cowpea Cultivars Under Osmotic Stress and Salicylic Acid

Abstract

Cowpea is one of the major food crops in Northeast Brazil, where it is commonly cultivated in the semi-arid regions with limited water availability. It is important to study the elicitors associated with cowpea to mitigate any deleterious effects of abiotic stress on the initial establishment of this crop. In this study, we aimed to evaluate the morphophysiological changes in cowpea cultivars under osmotic stress with seeds soaked in salicylic acid. The germination test was conducted in B.O.D germination chambers. The seeds of three cowpea cultivars: BRS Tumucumaque, BRS Aracê, and BRS Guariba, were germinated at five osmotic potentials (0.0; -0.2; -0.4; -0.6, and -0.8 MPa) after three pre-treatments: pre-soaking in deionized water, pre-soaking in salicylic acid, and without pre-soaking. The following parameters were evaluated: germination, germination speed index, seedling height, total phytomass, contents of chlorophyll ‘a’ and ‘b’, carotenoid content, electrolyte leakage, water content, and proline content. Our results indicate that salicylic acid promotes reduction in the harmful effects of abiotic stress, which is reflected in the increase in germination percentage, seedling height, and chlorophyll and carotenoid content as well as in the adjustment of electrolyte leakage and increase in proline content under induced water stress conditions. The cultivar BRS Guariba proved to be more tolerant to water deficit during germination and initial growth stages, when the seeds were treated with salicylic acid (1 mM).

Screening of worldwide cowpea collection to drought tolerant at a germination stage

“…In the present work, the decrease of seed germination rate was indeed more evident that the decline in germination (%, six days after sowing) and one of the most pronounced parameters under study. This result is in accordance with other cowpea studies, where the seed germination rate (GR) also decreased with drought stress induced by PEG-6000 (Araújo et al, 2018;Ferreira et al, 2017;Murillo-Amador et al, 2002). Several cowpea genotypes revealed significant alterations in their germination with PEG-6000 treatments, while others were not so affected, suggesting that distinct genotypes could be differently disturbed by drought.…”

Effects of irrigation water salinity and salicylic acid on germination and vigor of Mesosphaerum suaveolens (L.) Kuntze

“…As it is considered a growth regulator, SA can stimulate both the germination process and seed vigor, resulting in a faster germination process. Salicylic acid acts by regulating plant growth, acting on the physiological processes associated with germination and growth, reducing the harmful effects promoted by abiotic stresses, including salinity and defense mechanisms (E. D. Araújo, Melo, Rocha, Carneiro, & Rocha, 2018).…”

Ácido salicílico atenua o efeito do estresse hídrico na germinação e crescimento inicial de plântulas de <i>Cereus jamacaru</i> DC

“…Fato constatado em feijão (Vigna unguiculata Walp.) sob déficit hídrico [14], em alfazema brava [Mesosphaerum suaveolens (L.) Kuntze] em condições de estresse salino [12].…”