EFFECT OF OSMOTIC STRESS ON SEED GERMINATION AND SEEDLING GROWTH OF WHEAT (Triticum aestivum L.) AND AMARANTH (Amaranthus hypochondriacus L.)

Abstract

The effect different osmotic potential (Ψ s): 0, -0.05, -0.1, -0.2, -0.4, -0.8 and -16 (MPa) on water absortion, seed germination and seedling growth of wheat (Triticum aestivum L.) and amaranth (Amaranthus hypochondriacus L.), was etudied, and also synthesis and degradation (decrease or disappearance) of proteins under these conditions were analyzed. Wheat and amaranth seeds at 0 MPa absorb 94-95 % of their weight as water in 72 h, whereas at -1.6 MPa 30 % and 20 % of increase was observed for wheat and amaranth, respectively. Moreover, more than 50 % of water absortion occurs between 0-24 h for wheat and 0-12 h for amaranth seeds, independently of the Ψ s applied. At -0.8 MPa seeds germination was inhibited in wheat, although the effect on plant growth is not equality affected. On the other hand, amaranth seeds germinated even at -1.6 MPa, but there was not further seeding growth.
The protein synthesis that is usually found in the germinating wheat seeds under normal conditions was inhibited by NaCI, but in amaranth an Ψ s of -1.6 MPa mimics the protein pattern proper of the dry seed. Finally, NaCI avoided mobilization (utilization-degradation) of storage proteins in amaranth seeds.