肉桂酸对豇豆根系毒害作用的研究

Effect of Cinnamic Acid on Roots of Cowpea (Vigna unguiculata L.)

为探究豇豆主要根系分泌物肉桂酸对豇豆根系的毒害作用,本研究以2种抗性差异品种豇豆特早30号(TZ30)和紫秋豇6号(ZQJ6)为试验材料,在水培条件下,施用0.2 mmol·L-1肉桂酸,测定并分析根系的生理生化指标。结果表明,肉桂酸处理对2种豇豆根系均有明显毒害作用,2种豇豆的总根长、总根表面积、总根体积、总根尖数均显著下降,但TZ30比ZQJ6降幅小,具有较高抗性。TZ30的平均根系直径升高,无显著性差异;ZQJ6的平均根系直径升高,呈显著性差异,表明TZ30的抗性较高,并说明肉桂酸对豇豆根系的影响主要在幼嫩根系部位。2种豇豆根系的超氧化物歧化酶(SOD)、过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)活性均显著升高,说明豇豆可以通过提高抗氧化酶的活性来抵抗肉桂酸的自毒作用,其中TZ30的3种抗氧化酶活性提高程度均高于ZQJ6,说明TZ30对肉桂酸的抗性强于ZQJ6。2种豇豆的根系相对电导率均显著增加,根系可溶性蛋白含量均显著下降,说明肉桂酸破坏了豇豆根系的细胞结构,其中TZ30的根系相对电导率增加程度和可溶性蛋白下降程度均较ZQJ6高,说明TZ30的细胞结构受损害更严重。本研究分析了豇豆主要根系分泌物肉桂酸对不同抗性品种豇豆根系的毒害作用,为预防和克服豇豆自毒作用提供了一定的理论基础。

In order to explore effect of cinnamic acid on roots of cowpea, two different resistant varieties cowpea TZ30 and ZQJ6 were used to treat with 0.2 mmol·L-1 cinnamic acid under hydroponic condition,and the physiological and biochemical indexes of the roots were measured and analyzed. Results showed that Cinnamic acid treatment had obvious toxic effects on both cowpeas,the total root length, total root surface area, total root volume, and total number of root tips of the two cowpea species were significantly decreased by cinnamic acid treatment, TZ30 show less decrease, reflecting higher resistance of TZ30. The mean root diameter of TZ30 increased without significant difference, and the average root diameter of ZQJ6 increased with significant difference, reflecting higher resistance of TZ30, which indicated that the influence of cinnamic acid on cowpea roots was mainly presented in young roots. The activity of superoxide dismutase(SOD), peroxidase(POD) and ascorbate peroxidase(APX) on roots of the two kinds of cowpea were increased significantly, suggesting that cowpea resistance the effect of cinnamic acid by increasing the activity of antioxidant enzymes. The activity of antioxidant enzymes of TZ30 improved higher than ZQJ6, which means that cinnamic acid resistance of TZ30 is higher than ZQJ6. Both varieties of cowpea showed significant increase in relative electrical conductivity and significant decrease in soluble protein content, indicating that cinnamic acid destroyed cell structure of cowpea root system. Among them, TZ30 root system showed more increase in relative electrical conductivity and more decrease in soluble protein than ZQJ6, indicating that TZ30 cell structure suffered more serious damage. The results of this study analyzed the toxic effect of cinnamic acid from the main root secretions of cowpea on the root systems of different resistant cowpea varieties, and provided a theoretical basis for preventing and overcoming the autotoxic effects of cowpea.