Apoplastic sugars, fructans, fructan exohydrolase, and invertase in winter oat: Responses to second-phase cold hardening
Apoplastic sugars, fructans, fructan exohydrolase, and invertase in winter oat: Responses to second-phase cold hardening
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DOI：
10.1104/pp.116.1.403
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发表时间：
1998-01-01
期刊：
影响因子：
7.4
通讯作者：
Henson, CA
中科院分区：
文献类型：
--
作者：
Livingston, DP;Henson, CA
测定了冷硬化过程中燕麦（Avena sativa L., cv Wintok）树冠组织外体碳水化合物浓度和碳水化合物降解酶活性的变化。在第二阶段硬化（-3℃3天）期间，外质体中果聚糖、蔗糖、葡萄糖和果糖的含量明显高于未硬化和第一阶段硬化的植株。第二相硬化过程中外质体果聚糖的增加程度随果聚糖聚合程度（DP）的不同而不同（例如DP3和DP4比DP7和DP7增加的程度更大）。冠外体转化酶和果聚糖外水解酶的活性比未硬化和第一期硬化植株增加了约4倍。通过苹果酸脱氢酶活性测定，从未硬化、第一阶段硬化和第二阶段硬化的冠组织中提取的外体液具有低水平的共塑污染。讨论了这些结果对提高第二相硬化的耐冻性的意义。
Changes in apoplastic carbohydrate concentrations and activities of carbohydrate-degrading enzymes were determined in crown tissues of oat (Avena sativa L., cv Wintok) during cold hardening. During second-phase hardening (-3 degrees C for 3 d) levels of fructan, sucrose, glucose, and fructose in the apoplast increased significantly above that in nonhardened and first-phase-hardened plants. The extent of the increase in apoplastic fructan during second-phase hardening varied with the degree of fructan polymerization (DP) (e.g. DP3 and DP4 increased to a greater extent than DP7 and DP > 7). Activities of invertase and fructan exohydrolase in the crown apoplast increased approximately 4-fold over nonhardened and first-phase-hardened plants. Apoplastic fluid extracted from nonhardened, first-phase-hardened, and second-phase-hardened crown tissues had low levels, of symplastic contamination, as determined by malate dehydrogenase activity. The significance of these results in relation to increases in freezing tolerance from second-phase hardening is discussed.