外源ABA对冬小麦越冬期蔗糖代谢的影响

以抗寒品种‘东衣冬麦l号’和冷敏感品种‘济麦22’为试验材料，在三叶期时对叶片喷施ABA。在冬小麦越冬期间对叶片和分蘖节取样，研究外源ABA对越冬期低温下冬小麦的蔗糖含量及蔗糖代谢相关酶活性的影响。结果表明，外源ABA处理使低温下2个冬小麦品种积累了更多的蔗糖，尤其是‘东农冬麦1号’的分蘖节。零上低温时外源ABA促进了尿苷二磷酸一葡萄糖焦磷酸化酶（UGP）在蔗糖的合成中起主要作用，在零下低温时外源ABA则促进了UGP在蔗糖分解中起作用；外源ABA提高了‘东农冬麦1号’叶片和分蘖节以及‘济麦22’分蘖节中蔗糖磷酸合成酶、蔗糖合成酶的活性，但‘济麦22’叶片中这两种酶的活性则受到ABA的抑制；外源ABA也不同程度地促进了2＋-小麦品种叶片和‘济麦22’分蘖节中酸性转化酶和碱性转化酶活性的提高，但却抑制了‘东农冬麦1号’分蘖节中两种酶活性的提高，表明抗寒性强的‘东农冬麦1号’对外源ABA可能更加敏感，其越冬器官分蘖节保持了较高的蔗糖水平，其蔗糖合成能力的提高将有利于冬小麦植株抵御低温，进而维持＋a＋k-的存活。

Effects of Exogenous Abscisic Acid on Winter Wheat Key Enzymes of Sucrose Metabolism in the Wintering Period

Two winter wheat cultivars freezing-tolerant ＇Dongnongdongmai 1＇ and freezing-sensitive ＇Jimai 22＇ were used for materials, and leaves were sprayed withABA when seedlings were at the 3-true-leaf stage. Leaves and tillering nodes were sampled when seedlings were in the wintering period to study effects of exogenous ABA on sucrose content and activities of sucrose metabolism. The results indicated that with the temperature decrease in the wintering period, sucrose content in leaves and tillering nodes of two wheat varieties increased especially in tillering nodes of ＇Dongnongdongmai 1＇. UGP were promoted played a major role in the synthesis of sucrose activity by exogenous ABA at low temperature above 0 ℃, and were promoted played a major role in the decomposition of sucrose in freezing temperature. Activities of sucrose phosphate synthase （SPS） and sucrose synthase （SS） were promoted by exogenous ABA in the leaves and tillering nodes of ＇Dongnongdongmai 1＇ and tillering nodes of ＇Jimai 22＇, but were inhibited in the leaves of ＇Jimai 22＇. Acid invertase （SAInv） and alkaline invertase （ALInv） activities were improved by exogenous ABA to varying degrees in the leaves of ＇Dongnongdongmai 1＇ and in the leaves and tillering nodes of ＇Jimai 22＇, but activities of two enzymes were inhibited by exogenous ABA in tillering nodes of ＇Dongnongdongmai 1 ＇. These showed that ＇Dongnongdongmai 1＇ with strong cold resistance could be more sensitive to exogenous ABA, and made its over wintering organs tillering nodes maintaining a higher level of sucrose, sucrose synthesis and decomposition capabilities would benefit wheat against low temperature stress, and thus maintaining the survival of plant.