Effects of drought preconditioning on freezing tolerance of perennial ryegrass

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• 作者：Lindsey Hoffman^a ; Michelle DaCosta^a ; ^{mdacosta@psis.umass.edu} ; J. Scott Ebdon^a ; Jiuzhou Zhao^b
• 关键词：APX ; ascorbate peroxidase ; CAT ; catalase ; DP ; drought preconditioning ; LT50 ; lethal temperature resulting in 50%mortality ; MDS ; total mono- and disaccharides ; POD ; guaiacol peroxidase ; SC ; total storage carbohydrates ; SOD ; superoxide dismutase ; WW ; well-
• 刊名：Environmental and Experimental Botany
• 出版年：2012
• 期刊代码：39_00988472
• 类别：abs
• 出版时间：July, 2012
• 卷：79
• 期：Complete
• 页码：11-20
• 文件大小：510 K

摘要

Predicted increases in winter temperatures may negatively impact winter survival by preventing maximal cold acclimation prior to freezing temperatures. Accordingly, research is needed to identify strategies that may help promote cold acclimation and increase freezing tolerance. Therefore, the objectives of this research were to (i) examine the effects of drought preconditioning (DP) on freezing tolerance of two perennial ryegrass (Lolium perenne L.) cultivars (鈥楤uccaneer鈥?and 鈥楽unkissed鈥? under both non-cold acclimating (20 掳C) and cold acclimating (2 掳C) conditions; and (ii) examine the physiological and biochemical changes in leaves and crowns of perennial ryegrass in response to DP. Plants of 鈥楤uccaneer鈥?and 鈥楽unkissed鈥?perennial ryegrass were subjected to the following treatments in a controlled environment chamber: (i) well-watered at 20 掳C, (ii) DP at 20 掳C, (iii) well-watered at 2 掳C, and (iv) DP at 2 掳C. Leaf and crown tissues were harvested for analysis of freezing tolerance (lethal temperature resulting in 50%mortality, LT₅₀), nonstructural carbohydrates, proline, soluble protein, and antioxidant enzyme activities. Drought preconditioning resulted in an improvement in freezing tolerance (lower LT₅₀) for Buccaneer, but had no significant effect on freezing tolerance of Sunkissed. Furthermore, DP resulted in increases in carbohydrate, proline, and soluble protein contents, but this response was dependent upon cultivar, tissue, and temperature regime.