Loss of Desiccation Tolerance in Seeds of Tree Species During Germination: Theoretical and Practical Implications

Abstract

Understanding the loss of desiccation tolerance is of great importance in seed technology for its implications in the development of strategies for seed conservation and seedling production. In the present work, the loss of desiccation tolerance was studied in seeds of tree species Bowdichia virgilioides, Libidibia ferrea, Cedrela fissilis, Enterolobium contortisiliquum, Handroanthus impetiginosus, and Piptadenia gonoacantha. The seeds were collected in the region of Lavras, MG, and subjected to desiccation experiments individually for each species. Imbibition curve was created for each species by measuring seed weight at regular intervals under germination conditions. Based on this information, the seeds were allowed to imbibe for a time inferred from the imbibition curve, and then allowed to dry until reaching the initial water content measured before the imbibition begun. Then, the seeds were rehydrated, and those that developed into normal seedlings were considered desiccation-tolerant. The loss of seed desiccation tolerance followed a specific pattern in each studied species, but none of the species was tolerant to desiccation after radicle protrusion. A drastic decrease in desiccation tolerance was observed in P. gonoacantha seeds at the beginning of the germination process. Under the conditions implemented in this study, the loss of desiccation tolerance in all species started at the beginning of the germination process. These results have implications in both theoretical studies (seed priming) and the practice (in seedling production).

VIABILIDAD DE SEMILLAS DE PICH (Enterolobium cyclocarpum (Jacq.) Griseb.) CONSERVADAS EN CONDICIONES DE REFRIGERACIÓN

“…Sus frutos y semillas sirven para la elaboración de objetos artesanales (Francis, 1988;Beutelspacher, 2009). Crece particularmente en suelos del tipo Vertisol, los cuales se caracterizan por ser arcillosos, asimismo es tolerante a inundaciones temporales (Vázquez, Batis, Alcocer, Gual & Sánchez, 1999 Las semillas tienen una dormición física seguramente por la presencia de macroesclereidas y pudiera ser una especie ortodoxa como el pacará u oreja de negro 'Enterolobium contortisiliquum ' (Souza, Rocha, Oliveira, José & Amaral de Melo, 2018;Ferraz, Pereira & Rodrigues, 2019). El almacenamiento de las semillas en condiciones de refrigeración, es una práctica generalizada en semillas ortodoxas porque las bajas temperaturas evitan su deterioro físico y fisiológico (Conduru, Vieira.…”