| Tall fescue is one of the most common used cool-season turfgrass species. The physiological and biochemical characteristics under stressed conditions were studied in the present research. As a new regulator for plant growth, ALA plays an important role in mitigating stressed environment. Using two cultivars’Justice" and’Barlexsa’ of tall fescue as materials,we examined physiological and biochemical characteristics in response to exogenous ALA under drought and post-drought rehydration.Two-factor randomized block design was utilized to analyze effects of exogenous ALA on tall fescue during drought and post-drought recovery. Turf quality, leaf relative water content, electrolyte leakage, chlorophyll, carotenoids, soluble protein, carbohydrates, sucrose metabolism related enzymes activities were measured at0,5,10,15,20days of drought periods and10days of rehydration,respectively. The main results were as follows:1. Drought significantly suppressed the growth and development of’Justice’and ’Barlexsa’, with lower quality and relative water content. In addition, drought imposed significant influence on physiological and biochemical indexes, including the higher membrane electrolyte leakage, lower chlorophyll content, carotenoid content, storage carbohydrate (SC), as well as increasing accumulation of soluble sugar and soluble protein. Activities of sucrose phosphate synthase (SPS), sucrose synthase (SS) and acid invertase (AI) were enhanced under drought stress.2. The physiological and biochemical characteristics recovered to some extent at10d of rehydration. Additionaly,’Barlexsa’ showed higher recovery ability.3. Spraying exogenous ALA significantly mitigated adverse effects under drought but not well-watered condition. It significantly improved leaf relative water and chlorophyll content and decreased electrolyte leakage and soluble sugar content. All these results showed that spraying exogenous ALA increased drought-tolerance to some extent in tall fescue. |
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