Changes in carbohydrates accumulation in Viguiera discolor Baker in response to water deficit

ABSTRACT Water stress is an environmental factor that can regulate growth, limit production and lead to physiological and biochemical changes. Plants present a series of adaptive responses to drought, such as osmotic adjustment, in which carbohydrates play an important role. To evaluate the influence of water deficit on carbohydrates accumulation in V. discolor, the plants were divided into two groups: daily watering and water suppression for 14 days being re-watering after this period. Leaves and roots were collected at 0, 3, 6, 9, 12, 15 and 18 days, for ecophysiological and biochemical analyzes. Variations in carbohydrate contents in V. discolor showed a close relationship with changes in the plant water status, with higher concentrations of soluble sugars, total fructans, oligosaccharides, reducing sugars coinciding with the lower values of soil moisture and leaf water potentials and relative water content. In the tuberous roots, there is an increase in carbohydrate concentrations after re-watering. The increase of these low molecular weight carbohydrates is involved in osmotic adjustment and therefore acts to protect against dehydration.

摘要：水分胁迫是一类可调控植物生长、限制产量形成并诱发生理生化变化的环境胁迫因素。植物会针对干旱产生一系列适应性响应，例如渗透调节，其中碳水化合物发挥着关键作用。为探究水分亏缺对变色菝葜（V. discolor）体内碳水化合物积累的影响，本实验将供试植株分为两组：每日正常浇水组与持续控水14天后复水的控水组。分别于第0、3、6、9、12、15和18天采集植株叶片与根系样品，用于生态生理与生化指标分析。变色菝葜体内碳水化合物含量的变化与植株水分状态的改变密切相关：当土壤含水量、叶片水势及相对含水量处于较低水平时，可溶性糖、总果聚糖、寡糖与还原糖的含量均显著升高。复水后，块根中的碳水化合物浓度呈现上升趋势。这类低分子量碳水化合物的积累参与渗透调节过程，进而发挥抵御脱水胁迫的保护作用。