Physiological Characteristics of Low Temperature Tolerance in Poa pratensis Seedling Stage
In order to explore the differences in physiological characteristics of Poa pratensis seedlings with different resistance to low-temperature stress,a total of ten widely utilized P.pratensis varieties were used as experimental materials,and the seedling leaves were subjected to different degrees of low-temperature stress,and the cell damage rate and corresponding low temperature gradient were used to fit the Logistic equations.The semi-lethal temperature(LT50)was obtained,and cold-resistant varieties and low-temperature sensitive varieties were screened,and the relevant physiological parameters were deter-mined and the correlation analyses was carried out.The findings indicated that the LT50 of P.pratensis'Prafin'was-17.5℃,showing good cold resistance,and the LT50 of'Empire'was-3.2℃,showing low temperature sensitivity.After low-temperature stress treatment,the relative conductivity and malondi-aldehyde content of cold-resistant variety'Prafin'decreased significantly and were lower than that of low temperature sensitive variety'Empire'.The growth indexes such as dry matter content,relative water con-tent and seedling length,chlorophyll content,osmoregulatory substances(free proline,soluble sugars and soluble proteins)and antioxidant enzyme activities(SOD,POD and CAT)of'Prafin'seedlings were higher than those of'Empire'seedlings.The correlation analysis indicated that low temperature had great effects on the dry matter,seedling length and root length,and the content of osmoregulatory substances in P.pratensis seedlings and there was interaction between indicators.
Poa pratensisLow temperature stressSemi-lethal temperaturePhysiological character-isticsCorrelation
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