台湾鱼木对干旱胁迫的生理响应

通过盆栽控水试验,测定台湾鱼木在不同干旱条件下生长、生理指标的变化,研究台湾鱼木对干旱胁迫的生理响应。结果表明:在干旱初期,丙二醛(MDA)浓度上升,植物细胞膜受到一定程度的损伤,随之可溶性糖(SS)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性增加,阻止或减少羟基自由基的形成,抵御活性氧伤害膜保护系统。在干旱中期,渗透调节物质可溶性糖(SS)含量增加,过氧化物酶(POD)活性增强,表明植物细胞启动渗透调节和抗氧化酶系统避免干旱胁迫对植物细胞产生损伤。在干旱后期,丙二醛(MDA)呈现逐渐递增的趋势,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性由峰值下降；叶片相对含水量逐渐降低。相对叶绿素含量(SPAD)初期增加,随后呈现下降趋势,表明抗氧化酶系统超过了调节极限,植物细胞受到了严重损伤。结论:台湾鱼木通过渗透调节和启动抗氧化酶系统,对干旱胁迫表现出一定耐受性,在土壤相对含水量为27.78%时,达到耐受极限。台湾鱼木作为乡土树种之一,可以在我国热带亚热带地区的城市园林中应用推广。

Physiological response of Crateva formosensis under drought stress

Through a potted water control experiment, the physiological response of Crateva formosensis to drought stress was studied. The results showed that in the early stages of drought, the concentration of malondialdehyde (MDA) increased, and the plant cell membrane was damaged to a certain extent. As a result, the activities of soluble sugars (SS), superoxide dismutase (SOD), and catalase (CAT) increased, preventing or reducing the formation of hydroxyl radicals and resisting the damage of reactive oxygen species to the membrane protection system. In the middle stage of drought, the content of soluble sugars (SS) in osmotic regulating substances increases, and the activity of peroxidase (POD) increases. In the later stage of drought, malondialdehyde (MDA) shows a gradually increasing trend, and the activities of superoxide dismutase (SOD) and catalase (CAT) decrease from their peak. The relative water content of the leaves gradually decreases. The relative chlorophyll content (SPAD) initially increased and then showed a downward trend. Conclusion: Crateva formosensis exhibit certain tolerance to drought stress through osmotic regulation and activation of antioxidant enzyme systems, reaching tolerance limits at a relative soil moisture content of 27.78%. Crateva formosensis, as one of the local tree species, can be applied and promoted in urban gardens in tropical and subtropical regions of China.