evaluation of cold stress tolerance in several species of grasses by electrolyte leakage test

abstract the grasses cold tolerance is the most important limiting factor for its cultivation in temperate regions, so using cold tolerant cultivars is essential for grasses successful cultivation. in order to evaluation freezing stress tolerance of several species of grasses, this study was conducted in agricultural faculty of ferdowsi university of mashhad as a factorial complete randomized block design with three replications. experimental factors included six types of grasses and 14 freezing temperatures. to assess grasses cold tolerance, electrolyte leakage test and lt50 for leaf and crown tissues was used. the results showed that reduction of freezing temperature, increased electrolyte leakage percent from leaf and crown tissues and difference between the grasses was significant. the effect of freezing temperatures on electrolyte leakage from leaf tissue was higher than the crown. maximum level of electrolyte leakage from leaf tissue (at -16.5 °c) was 90 percent, while the maximum leakage from crown tissue (at -18 °c) was 76 percent. based on leaf lt50, ecotype mahalat and bermudagrass were the most cold sensitive and starlet and ecotype yarand were the most cold tolerant grasses. the crown electrolyte leakage and lt50 were different between grasses significantly. accordingly, crown electrolyte leakage percent was minimum for starlet and maximum for mahalat and crown lt50 index was minimum for mahalat and maximum for yarand.