Adaptation to flooding in upland and lowland ecotypes of Cyperus rotundus, a troublesome sedge weed of rice: tuber morphology and carbohydrate metabolism
Adaptation to flooding in upland and lowland ecotypes of Cyperus rotundus, a troublesome sedge weed of rice: tuber morphology and carbohydrate metabolism
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DOI：
10.1093/aob/mcn085
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发表时间：
2009-01-01
期刊：
影响因子：
4.2
通讯作者：
Johnson, David E.
中科院分区：
文献类型：
--
作者：
Pena-Fronteras, Jennifer T.;Villalobos, Mizpah C.;Johnson, David E.
近年来，在菲律宾，香附子已成为与蔬菜轮作的低地水稻（Oryza sativa）中的问题杂草。随着C.长时间的洪水通常会抑制这种杂草的生长，但这种杂草在洪水和高地条件下旺盛生长的能力表明，在这些轮作中出现了适应的生态型。进行了研究，以阐明机制，允许C。高地和低地两种生态类型的C.从生长习性、碳水化合物的储存和代谢、酒精发酵相关酶-乙醇脱氢酶（ADH）和丙酮酸脱羧酶（PDC）活性等方面比较了低地种圆薯的生长特性。发芽前，低地植株块茎中淀粉酶活性和可溶性糖形式的非结构性碳水化合物总含量高于旱地植株。圆的在低氧条件下，低地植物萌发后24 h PDC和ADH活性升高，萌发后48 h下降。而高地植株的ADH和PDC活性则在萌发后24 ~ 48 h呈上升趋势。圆形的淹水可归因于大的碳水化合物含量和淀粉酶活性，以及在发芽和早期生长期间在块茎中维持高水平的可溶性糖的能力。这与萌发过程中ADH和PDC活性的调节相结合，可能是为了控制碳水化合物储备的使用并维持基质供应，以避免幼苗因长时间淹水而饥饿和死亡。
In recent years, Cyperus rotundus has become a problem weed in lowland rice (Oryza sativa) grown in rotation with vegetables in the Philippines. As the growth of C. rotundus is commonly suppressed by prolonged flooding, the ability of the weed to grow vigorously in flooded as well as upland conditions suggests that adapted ecotypes occur in these rotations. Studies were conducted to elucidate the mechanisms that permit C. rotundus to tolerate flooded soil conditions.Upland and lowland ecotypes of C. rotundus were compared in terms of growth habit, carbohydrate reserves and metabolism, and activities of enzymes involved in alcoholic fermentation - alcohol dehydrogenase (ADH) and pyruvate decarboxylase (PDC).The lowland ecotype has much larger tubers than the upland ecotype. Prior to germination, the amylase activity and total non-structural carbohydrate content in the form of soluble sugars were greater in the tubers of lowland plants than in those of upland C. rotundus. At 24 h after germination in hypoxic conditions, PDC and ADH activities in the lowland plants increased, before decreasing at 48 h following germination. In contrast, ADH and PDC activities in the upland plants increased from 24 to 48 h after germination.Tolerance of lowland C. rotundus of flooding may be attributed to large carbohydrate content and amylase activity, and the ability to maintain high levels of soluble sugars in the tubers during germination and early growth. This is coupled with the modulation of ADH and PDC activities during germination, possibly to control the use of carbohydrate reserves and sustain substrate supply in order to avoid starvation and death of seedlings with prolonged flooding.