A Crucial Role for Gibberellins in Stress Protection of Plants

Abstract

The hypothesis that there is an intimate relationship between gibberellin levels and plant stress protection has been tested using near-isogenic lines of a normal and dwarf barley (.Hordeum vulgare L.). Application of paclobutrazol (a triazole), induced stress protection in the normal line and application of GA 3 to the dwarf reversed the inherent stress tolerance. Reversal of the dwarf phenotype by specific gibberellins (GAs) suggests that the conversion of GA20 to GAj and GA 9 to GA 4 has been compromised. These observations indicate that modulation of specific GAs plays a key role in stress protection. The preferential use of non-chemical technologies including enzyme regulation, phytochrome A overexpression, and breeding for induction of stress tolerance in plants are discussed.