Proline and trehalose in maize seeds germinating under low osmotic potentials

Although it is relatively well known that adult plants tend to accumulate proline and trehalose in their tissues as a physiological mechanism in response to drought, there is scarce information about the development of this physiological response in seeds. Thus, the objective of this research was to verify if maize seeds are able to develop mechanism of osmoprotection, when are germinating under low osmotic potential, and the possibility to use the levels of trehalose and proline in a defined seed part, aiming to differentiate genotypes regarding drought tolerance. The experiment was performed as a factorial arrangement of 2 x 5 (2 hybrids x 5 osmotic potential) within a completely randomized design, with four replicates. It was found that the proline content in the embryo axis of maize seeds germinating under water limitation is directly proportional to the intensity of this stress. Distinct hybrids show different proline levels accumulated in the embryo axis, when seeds are germinating under the same conditions of water limitation. The trehalose content tends to decrease in the embryo axis and in the endosperm of maize seeds germinating under increasing water limitation, but the reduction is not directly proportional to osmotic potential.