Escribe una PREreview

Drought is a major threat to global food security, with climate change enhancing its severity. Living organisms employ various adaptation strategies against loss of water, with desiccation tolerance representing the most extreme ones. The present study provides an analysis of desiccation response mechanisms in Pisum sativum L., focusing on the early seedling development. The experiments were carried out on 3-day-old seedlings with radicle up to 20 mm and similar seedlings with cotyledons removed, each subjected to the 'desiccation and rehydration' treatment. We assessed stress responses using growth and electrolyte leakage tests, and by measuring ascorbate content and lipid peroxidation products. The results demonstrated that while all desiccated seedlings experienced oxidative stress, seedlings with cotyledons exhibited superior recovery capacity, e.g. maintaining membrane integrity, ascorbate status and the ability to form the adventitious roots. We also monitored the ABA-dependent stress response by registering expression of several genes associated with "response to water deprivation" (ABI3, ABI4, ABI5, HVA22, PER1, LEA14, RD22-1/2/3, LTI65, and LTP4). Intrudingly, 'desiccation and rehydration' treatment resulted in the 40-fold up-regulation of ABI5 in hypocotyls of seedlings both with removed and intact cotyledons and the 108-fold up-regulation of this gene only in roots of seedlings with intact cotyledons. We propose that the post-germination stage represents a ‘resilience window’ where embryonic protective mechanisms remain partially active while the plant prepares for autotrophic growth. Herewith, the role of cotyledons extends beyond their classical role as nutrient reserves by coordinating both developmental and stress responses under conditions of severe water stress.