Abstract: Ten days after tall fescue plants being kept in a condition of 4℃ of daytime temperature and 2℃ of night temperature, the sugar content of the different parts of the p1ants rises sharply. The increase in the crown is the most marked, followed by that in the leaves and the roots. In a low temperature, the sucrose synthetase and sucrose phosphate synthetase activities of the crown are induced many times stronger than ever,whereas in the leaves only the sucrose phosphate synthetase activity is displayed. The proportion of the crown weight in the total plant weight increases steadily. In fact, the crown is an important organ that sustains the existence of the plant in stringent conditions. Vivid sucrose synthetase activity ensures the crown’s bearing capacity and enables it to assimilate sugar. It is the highly active sucrose phosphate synthetase that maintains the crown’s significant sugar content and enhances its cold resistance in low temperatures.

Key words: Grassland science, Low temperature, Sucrose synthetase, Sucrose phosphate synthetase, Tall fescue

摘要： 高羊茅植株经过10d低温锻炼(4/2℃,昼/夜),体内各部位的蔗糖含量急剧上升,上升幅度依次为茎基>叶片>根系;茎基的蔗糖合酶(SS)和磷酸蔗糖合酶(SPS)的活性皆成倍提高,而叶片仅表现为SPS活性提高;茎基占植株总干重的比值持续加大;茎基是高羊茅在逆境中维持生存的重要器官,高SS活性使其保持较高的卸载和吸纳蔗糖的能力,同时高SPS活性使其保持较高的蔗糖含量,从而提高茎基对低温的抵抗能力。

关键词: 草原学, 低温, 蔗糖合酶, 蔗糖磷酸合酶, 高羊茅