Key Laboratory of Agro-Environment in the Tropics, Ministry of Agriculture and Rural Affairs, Guangdong Engineering Research Center for Modern Eco-Agriculture and Circular Agriculture, Department of Ecology, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China.
Key Laboratory of Agro-Environment in the Tropics, Ministry of Agriculture and Rural Affairs, Guangdong Engineering Research Center for Modern Eco-Agriculture and Circular Agriculture, Department of Ecology, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China; School of Life Sciences, Guizhou Normal University, Guiyang 550025, China.
Environ Pollut. 2024 Oct 1;358:124519. doi: 10.1016/j.envpol.2024.124519. Epub 2024 Jul 8.
Biotic (e.g., heavy metal) and abiotic stress (e.g., insect attack) can affect plant chemical defense, but little is known about the changes in plant defense when they occur concurrently. Herein, the impacts of heavy metal cadmium (Cd) stress and insect herbivory stress on the direct and indirect defense of two cultivar cabbages of Brassica campestris, the low-Cd cultivar Lvbao701 and the high-Cd cultivar Chicaixin No.4, against the herbivore cutworm Spodoptera litura were investigated. Although 10 mg kg Cd stress alone inhibited leaf secondary metabolites (total phenolics, flavonoids), it reduced the feeding rate and odor selection of S. litura towards both cultivar cabbages, especially for Lvbao701, by increasing leaf Cd content and repellent volatile organic compounds (VOCs) (6-methyl-5-hepten-2-one, 7,9-di-tert-butyl-1-oxaspiro (4,5)deca-6,9-diene-2,8-dione), and reducing soluble sugar and attractive VOCs (3-methyl-3-pentanol, 2,5-hexanedione, tetradecanal). Under 2.5 mg kg Cd and herbivory stress, although leaf total phenolics and flavonoids increased significantly, the feeding rate and odor selection of S. litura towards both cultivar cabbages increased, especially for Chicaixin No.4, indicating that the chemical defense of cabbages was depressed. Therefore, Cd stress alone improved the insect resistance of cabbages, whereas herbivory stress weakened the enhanced cabbages defence by Cd stress. The low-Cd cultivar Lvbao701 presented stronger insect resistance than Chicaixin No.4, suggesting that Lvbao701 application in Cd-polluted soil can not only decrease Cd transmission to higher levels in the food chain but also reduce pest occurrence.
生物（如重金属）和非生物胁迫（如昆虫攻击）会影响植物的化学防御，但对于它们同时发生时植物防御的变化知之甚少。在此，研究了重金属镉（Cd）胁迫和昆虫取食胁迫对两个白菜品种 Brassica campestris 的直接和间接防御的影响，低 Cd 品种 Lvbao701 和高 Cd 品种 Chicaixin No.4，对鳞翅目夜蛾 Spodoptera litura 的食草性。虽然单独 10 mg kg Cd 胁迫抑制了叶片次生代谢物（总酚、类黄酮），但通过增加叶片 Cd 含量和增加叶片 Cd 含量，它降低了鳞翅目夜蛾对两种白菜的取食率和气味选择，特别是对 Lvbao701，对挥发性有机化合物（VOCs）（6-甲基-5-庚烯-2-酮，7,9-二叔丁基-1-氧杂螺（4,5）癸-6,9-二烯-2,8-二酮）的排斥，以及降低可溶性糖和有吸引力的 VOCs（3-甲基-3-戊醇，2,5-己二酮，十四醛）。在 2.5 mg kg Cd 和取食胁迫下，尽管叶片总酚和类黄酮显著增加，但鳞翅目夜蛾对两种白菜的取食率和气味选择增加，特别是对 Chicaixin No.4，表明白菜的化学防御受到抑制。因此，单独的 Cd 胁迫提高了白菜的抗虫性，而取食胁迫削弱了 Cd 胁迫增强的白菜防御。低 Cd 品种 Lvbao701 表现出比 Chicaixin No.4 更强的抗虫性，这表明在 Cd 污染土壤中应用 Lvbao701 不仅可以降低 Cd 向食物链更高水平的传递，还可以减少害虫的发生。
