Seed discontinuous hydration does not benefit germination, but improves drought tolerance of Triplaris gardneriana seedlings

Abstract

The discontinuous seed hydration enables the acquisition of tolerance to environmental stresses, causing a stress imprint. It may modify metabolic patterns and lead to improved stress responses. This study aims to evaluate the effects of discontinuous hydration on germination and on seedling growth of Triplaris gardneriana Wedd. under intermittent drought. The seeds have gone through cycles (0, 1, 2 and 3) of hydration and dehydration (HD). The seedlings produced were subjected to water deficit (daily watering and intervals of seven and fourteen days between watering). Seed germinability parameters and, relative growth rate (RGR) of seedling, leaf area, dry matter yield and leaf relative water content (RWC) were evaluated. The HD cycles did not benefit germination, but two HD cycles induced a better biomass accumulation and increased leaf area in seedlings under moderate water deficit, while three HD cycles promoted an increase in RGR and influenced the RWC values. Severe stress affects seedling growth, but subjection to HD cycles minimizes the deleterious effects of drought, suggesting discontinuous hydration acts leading stress imprint in plants.

O hidrocondicionamento afeta a germinação e sobrevivência de Piptadenia moniliformis

“…Sabe-se que o teor de água da semente influencia a taxa e velocidade de absorção de água (Lopes et al, 2022). Embora a literatura relate muitos benefícios da hidratação descontínua de sementes (Lima et al, 2018b;Freitas et al, 2021;Nascimento et al, 2021;Jain et al, 2022), algumas espécies como Myracrodruon urundeuva,…”

“…Nesse cenário, as sementes enfrentam ciclos sucessivos de hidratação e desidratação no solo até que as condições sejam favoráveis a germinação e o estabelecimento das plantas (Paparella et al, 2015;Farooq et al, 2019). Entretanto, há evidências de que esses ciclos de hidratação e desidratação beneficiam a germinação e a sobrevivência das mudas de algumas espécies, especialmente em condições de restrição hídrica ou baixos potenciais osmóticos (Lima et al, 2018a;Freitas et al, 2021;Nascimento et al, 2021;Santos Júnior et al, 2021;Jain et al, 2022), enquanto, para outras, os efeitos são danosos (Hora e Meiado, 2016;Lima et al, 2018b). Durante a hidratação descontínua, os processos metabólicos e bioquímicos que antecedem a germinação são estimulados e interrompidos (Lima et al, 2018a(Lima et al, , 2018b.…”

Interpopulational seed hydration memory does not affect seed germination of Xiquexique gounellei (F.A.C.Weber ex K.Schum) Lavor & Calvente subsp. gounellei (Cactaceae) under water deficit

“…(Fabaceae) (Lima et al, 2018a) and Triplaris gardneriana Wedd. (Polygonaceae) seeds (Freitas et al, 2021).…”

“…We can highlight as an example the case of discontinuous hydration of Triplaris gardneriana seeds, which shows a neutral effect during seed germination. However, seedlings originated from these hydroprimed seeds are favoured by the discontinuous hydration of the seeds during growth under water deficit conditions (Freitas et al, 2021). In this sense, during the initial development, HD cycles may favour the production of more vigorous seedlings, with greater length and stem diameter, greater weight of leaves, stems and roots, as well as increasing tolerance to environmental stresses (Sánchez-Soto et al, 2005; Alvarado-López et al, 2014; Lima & Meiado 2018b).…”