Germination response and alpha-amylase activity to temperature and light condition in four warm-season turfgrass species

To investigate the effect of light and temperature condition on germination of four warm- season turfgrass including; Buchloe dactyloides, Cynodon dactylon, Zoysia japonica and Paspalum vaginatom, an experiment was conducted in a completely randomized design with factorial arrangement in four replications. In this study, the treatments included four species of turfgrass, two light conditions (light-dark and continuous darkness) and four alternating temperature including: 10-35, 12.5-32.5, 15-30 and 17.5-27.5 degree Celsius (night-day respectively). In this study, the characteristics of percentage and rate germination, and alpha- amylase activity were measured. The results showed that these four species germinate better under light-dark conditions than continuous darkness. The highest germination in all four species occurred in light-dark in 15-30 ̊C. The lowest germination occurred in B. dactyloides and P. vaginatom, in continuous darkness and alternating temperatures of 10-35 ̊C. Germination rate showed that the highest germination rate was observed in Z. japonica at all levels of temperature regimes, and it was also found that the lowest germination rate was in B. dactyloides in 10-35 ̊C. The results of the interaction of temperature rotation and species type on the activity of alpha-amylase enzyme showed that the highest activity of this enzyme in all species was related to the temperature cycle of 17.5-27.5 ̊C. In this temperature cycle, B. dactyloides had the highest enzymatic activity compared to other species. Also, with increasing the temperature range, especially temperature of 10-35 ̊C, P. vaginatum showed a significant advantage over other species. In conclusion, these four types of turfgrasses needed light for germination and the appropriate temperature for their germination was 27.5 ̊C during the day and 17.5 ̊C at night. There was also a direct relationship between alpha-amylase activity and germination of these four species.