Polyamines and ethylene metabolism during cold acclimation in zoysiagrass (Zoysia Japonica Steud.)

Zoysiagrass (Zoysia japonica Steud.) is a warm-season turfgrass species well adapted for lawns and golf courses in transition zone and other regions with warm climates; however, it losses color and goes into dormancy in late fall and winter. The physiological mechanisms of cold acclimation (CA) have not been well understood. This growth chamber study was designed to investigate changes in leaf polyamines (PAs) and activities of selected enzymes, and ethylene production in response to CA. Leaf chlorophyll content and photosynthesis rate declined and cell membrane electrolyte leakage and malondialdehyde increased during CA. Putrescine (Put) and spermidine declined and then increased after 10 days during CA. Ethylene increases after 15 days of CA. Put biosynthesis enzymes (arginine decarboxylase, ADC, ornithine decarboxylase, ODC, s-adenosylmethionine decarboxylase), and diamine oxidases and polyamine oxidase activities increased in response to CA, except for ADC which increased after 10 days of CA. Accumulation of O-2- and H2O2 in leaf tissue was observed during CA. These results suggest that PAs and ethylene are involved in CA in zoysiagrass.