COMPARISON OF DEHYDRIN GENE-EXPRESSION AND FREEZING TOLERANCE IN BROMUS-INERMIS AND SECALE-CEREALE GROWN IN CONTROLLED ENVIRONMENTS, HYDROPONICS, AND THE FIELD

There have been very few reports on the expression of stress-responsiv e genes in field-grown material. A barley dehydrin cDNA was used to in vestigate the expression of dehydrin-like transcripts after low-temper ature and abscisic acid-induced acclimation of bromegrass (Bromus iner mis Leyss) suspension cells and of bromegrass and rye (Secale cereale) plants grown in the field and under controlled environmental conditio ns. Field-acclimated plants accumulated high levels of dehydrin transc ripts and were very freezing tolerant. Plants grown in pots and hydrop onics under controlled environments also accumulated dehydrin transcri pts and showed increased freezing tolerance. Simulation of a combined drought and freezing stress in pots resulted in expression of dehydrin -like transcripts comparable to those observed in field-acclimated mat erial.