THE NATURAL PROTECTION AND REPAIR MECHANISM: THE ORCHESTRATION OF SEED VIGOR
Dirk, L.M.A.1, Zhao, T-Y.2, Unêda-Trevisoli, S.H.3 and Downie, A.B.1
1Department of Horticulture, University of Kentucky, Lexington, Kentucky, USA
2College of Life Sciences, Northwest Agriculture and Forestry University, Yangling, Shannxi, PRC
3Dept. Crop Science, UNESP, University of São Paulo State, Jaboticabal, SP, Brazil
Contact: A. Bruce Downie, email@example.com
Orthodox seed are those capable of surviving extreme dehydration (5-10% moisture content; anhydrobiosis) and constitute the majority of human nutrition. Anhydrobiosis permits facile global food transport and storage, forming the basis for classical agriculture by allowing a portion of each harvest to be stored to sow the next crop. An underappreciated role seeds play is in the encapsulation of technology in a transportable, storable, quantifiable entity. This seminar will be for those interested in the fundamental underpinnings of anhydrobiosis as it relates to seed vigor. The natural protection and repair mechanism (NPRM) has long been recognized, in orthodox seeds, as the means by which the cells comprising the propagule prepare for, and survive, extreme water loss. The NPRM is an umbrella term referring to any physical or physiological alteration that renders the cell: 1) more tolerant of water loss and attendant stresses and; 2) better able to repair the damage to macromolecules and cellular components, accrued during the sojourn in the dehydrated state, upon subsequent rehydration (imbibition). The more competent the cells comprising the seed are at performing these tasks, the greater their longevity and the more superior their vigor. Areas to be explored in this seminar will, therefore, include late embryogenesis, when protective mechanisms are deployed to prepare the cells for loss of water and metabolic quiescence. The subsequent existence in the dehydrated state will be analyzed focusing on what is occurring at the level of the cell that may possibly mitigate damage accrued when repair is at least limited by lack of water.