Effect of drought and heat stress and rewatering on photosynthetic physioecological characteristics of Kentucky turfgrass

Abstract

Five Kentucky bluegrass cultivars were made as trial material to study effect of drought-heat stress and rewatering on photosynthetic characteristics of turfgrass, experimental results will provide some theoretic reference for cultivating cool- season turfgrass and utilizing water efficiently in hot summer. The results indicated that soil weigh content (SWC), and 3 photosynthetic physiological parameters-leaf net photosynthetic rate ( Pn ), transpiration ratio ( Tr ), leaf photochemical efficiency( Fv/Fm) showed decreasing trend during the primary period of drought and heat stress, whereas stomatal conductance(Gs), and intercellular C02 concentration( Ci) showed slightly increasing trend; with the delay of treamental time, above 6 parameters of five cultivars showed different significant decreasing trend, but 5 photosynthetic physiological parameters of Award decreased more obviously than the ones of the other 4 cultivars. After rewatering treament, six parameters of all cultivars recovered obviously (except Award), rewatering treament 10 d later, all parameters could recover above 60 percent of normal level. These trial results suggested that drought-heat stress affected normal photosynthetic physiological metabolism of Kentucky bluegrasses cultivars, demonstrated by the decrease of leaf net photosynthetic rate(Pn), transpiration ratio (Tr), leaf photochemical efficiency (Fv/Fm), stomatal conductance ( Gs), and intercellular C02 concentration (Ci), meanwhile the change of photosynthetic parameters for five Kentucky bluegrasses under drought-heat stress, and rewatering treatment indicated that these turfgrasses have their self-adaptability to adversity from an aspect.