Influence of the thermal stress on some physiological features and survival of plants of Lolium perenne varieties Diament and Gagat

摘要

The aim of this paper was to estimate the freeze resistance of Lolium perenne varieties in controlled conditions. Two forage varieties of perennial ryegrass {Lolium perenne L.) - Diament and Gagat were examined in pure sowing in pot experiment at mineral soil. Plants in emergence and tillering phases were treated with low temperatures -5 deg C and -10 deg C for 24 hours. Leaf greenness index and chlorophyll fluorescence of selected varieties were measured using by standard methods and equipments. There were also recorded the number of shoots which survived after one week since thermal stress. The obtained results indicate that in analyzed plants of both Lolium perenne varieties exposed to low temperatures occurred significant decrease in chlorophyllcontent and fluorescence of chlorophyll comparing to the control. After one week since stress temperature the survival of shoots in tillering phase was clearly better than in emergence phase. It was found that the Diament variety characterized the bestsurvival of shoots.