ACTION OF GROWTH REGULATORS ON LUCERNE GERMINATION AND GROWTH UNDER WATER STRESS

Abstract

Lucerne seeds (Medicago sativa L.) were germinated in a range of polyethylene glycol (PEG) and sodium chloride (NaCl) solutions in the presence and absence of kinetin with ethrel. In addition, seeds were germinated in water and transferred to PEG and NaCl solutions, and root growth was measured. The water potentials at which there was 50% germination inhibition and at which 50 % of the germinated seeds failed to grow after transfer were determined. Kinetin and ethrel together completely removed the block to germination through osmotic stress, allowing germination to proceed at the same water potential as growth. The action of kinetin and ethrel was studied by following the processes of cell expansion and division during germination and early growth. The control of germination by water stress was through cell expansion, and the initiation of this process was shown to be stimulated in the presence of the growth regulators. Cell division although initially permitted in their presence, was later inhibited causing a decline and finally cessation of seedling growth. Copyright © 1980, Wiley Blackwell. All rights reserved