The Use of Coleoptile Responses to Water Stress to Differentiate Wheat Genotypes for Osmoregulation, Growth and Yield

Abstract

Differences in osmoregulation between genotypes of wheat (Triticum aestivum L.) were identified by measuring responses of coleoptiles to water stress. Seeds were germinated in Petri dishes on germination pads. Water stress was applied when coleoptiles were 1 cm long by either adding polyethylene glycol 6000 (20% w/w) or by removing the lids of the dishes and allowing the pads to dry by evaporation for a period of 2 d, or from the beginning of germination by varying the amount of water in the germination pads. Measurements of the water and osmotic potentials of shoots and roots (using thermocouple psychrometers) were used to estimate turgor pressures. Wheat genotypes showed the same segregation for shoot and root lengths and turgor pressures as they had done in previous studies for flag-leaf osmoregulation and yield. It was concluded that observations of the responses of coleoptile length to water stress could be used in plant-breeding applications to identify differences in osmoregulation between genotypes of wheat.