Abstract:

The objectives of the study were to explore the adaptive strategies of Fagopyrum dibotrys and the ability of tolerating drought, and to reveal drought resistance mechanisms of different materials. The seedlings of eight excellent germplasms were grown in greenhouse. The effects of drought stress on the cell injury rate, MDA (malondialdehyde) content, proline content, soluble sugar content, SOD (superoxide dismutase) activity, POD (peroxidase) activity, CAT (catalase) activity, physiological indexes and growth of F. dibotrys were investigated. The drought resistance of eight germplasm resources was comprehensively evaluated. The results showed that the accumulation of proline and soluble sugar could help to maintain their expansion pressure of cell, and that the increasing of antioxidase activities, such as SOD, POD and CAT could protect cell membranes from damage. Osmotic adjustment ability of soluble sugars was stronger than proline. SOD and CAT enzyme played a role firstly in the active oxygen scavenging reaction process. Drought-resistant plants enhanced their tolerance to drought stress by increasing the non-photochemical quenching, decreasing leaf area, stomatal conductance and transpiration rate, ensuring higher water use efficiency, and increasing belowground biomass to maintain soil moisture and nutrient use efficiency. The rank of drought tolerance of eight F. dibotrys germplasm resourses is as follows, JQ6 >JQ3 >JQ2 >JQ4 >JQ1 >JQ8 >JQ5 >JQ7.

Key words: Fagopyrum dibotrys, Drought resistance, Growth, Physiological and ecological parameters, Comprehensive evaluation

摘要：

为探讨金荞麦（Fagopyrum dibotrys）对持续干旱胁迫的适应对策和能力，揭示其抗旱机制，本试验以8个优异金荞麦种质为试验材料，采用室内盆栽模拟干旱胁迫法，研究持续干旱下金荞麦细胞膜脂过氧化、渗透调节物质、保护酶活性、光合及叶绿素荧光参数变化和植株生长情况，并利用主成分与隶属函数综合评价其抗旱性。结果表明，干旱胁迫下金荞麦的脯氨酸（Pro）、可溶性糖（SS）等渗透调节物质累积，维持细胞膨压；SOD，POD和CAT等抗氧化酶活性增加，保护细胞膜免遭伤害。SS的渗透调节能力强于Pro。SOD和CAT酶在活性氧清除反应过程中，首先发挥作用。抗旱性强的金荞麦非光化学猝灭升高，保护细胞及光合结构不受损伤；叶面积、气孔导度和蒸腾速率降低，地下生物量增加保证了较高的水分利用率。8个金荞麦材料的抗旱性顺序为：JQ6 >JQ3 >JQ2 >JQ4 >JQ1 >JQ8 >JQ5 >JQ7。

关键词: 金荞麦, 抗旱性, 生长, 生理生态指标, 综合评价