Metabolic Changes During Cold Acclimation and Deacclimation in Five Bermudagrass Varieties: II. Cytokinin and Abscisic Acid Metabolism

• Published in: Crop science 2011-03, Vol.51 (2), p.847-853
• Main Authors: Zhang, Xunzhong, Ervin, E.H, Waltz, C, Murphy, T
• Format: Article
• Language: English
• Subjects: Abscisic acid; acclimation; Acclimatization; Adaptation to environment and cultivation conditions; Agronomy. Soil science and plant productions; Biological and medical sciences; Cell division; Chromosomes; climate; Cold; cold tolerance; Cultivars; Cynodon dactylon; cytokinins; deacclimation; ecotypes; Flowers & plants; Freezing; Fundamental and applied biological sciences. Psychology; Gene expression; Genetics and breeding of economic plants; Growth chambers; metabolism; Metabolites; overwintering; Spring; temperature; Transition zone; Varietal selection. Specialized plant breeding, plant breeding aims
• ISSN: 1435-0653; 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2010.06.0346

Bermudagrasses (Cynodon spp.) grown in the U.S. transition zone and other regions with a similar climate undergo cold acclimation in fall and deacclimation in spring. Physiological mechanisms of cold acclimation and deacclimation associated with freezing tolerance and spring green-up are not well documented. This study investigated changes in cytokinin (t-zeatin riboside [t-ZR]) and abscisic acid (ABA) during cold acclimation and deacclimation in five bermudagrass entries in growth chambers. One ecotype (GA-851) and four cultivars (Patriot, Riviera, Tifway, and Princess-77) were subjected to cold acclimation at 8/4°C (day/night) for 28 d and then deacclimation at 10/5, 21/7, 23/8, and 26/14°C for either 3 wk (standard deacclimation) or 1 wk (fast deacclimation treatment). Stolon t-ZR content declined while ABA content increased during cold acclimation. Patriot and Riviera had higher levels of stolon ABA relative to Princess-77 at the end of cold acclimation. During deacclimation, t-ZR increased as the temperature increased to 26/14°C, while ABA declined as the temperature increased from 10/5 to 21/7°C. Patriot, GA-851, and Tifway had higher levels of t-ZR relative to Riviera and Princess-77. Abscisic acid level during cold acclimation may be associated with freezing tolerance, while cytokinin level during deacclimation may be associated with rate of spring green-up of bermudagrass. The results suggest that selection and use of entries with higher levels of ABA during cold acclimation and cytokinin during deacclimation could improve bermudagrass winter survival and spring green-up in transition zone climates.