The gall formation in Salix species is caused by Candidatus phytoplasma trifolii. The present study was designed with the aim of evaluation of the morphological and physiological response of two species of Salix alba and Salix babylonica to gallers in the witches^’ broom structure. The morphological responses of Salix species to gallers, denoted as biotic stress, were represented by growth suppression of leaves and shoots. Accordingly, the leaf area and shoot internodes significantly decreased, in comparison with healthy plants. The biotic stress can induce oxidative stress, which was observed in the present study with a high accumulation of H₂O₂ in galled tissues. High accumulation of H₂O₂ in the infected tissue damaged chlorophyll a and proteins. Even though Salix species induced the antioxidants catalase, peroxidase, proline, anthocyanins and phenols to scavenge reactive oxygen species (ROS), high accumulation of H₂O₂ was observed in galled tissues. Altogether, regardless of activation of antioxidants in response to galls-induced oxidative stress, ROS accumulation damaged photosynthetic apparatus and proteins.

柳属植物中的瘿形成是由三叶草植原体(Candidatus phytoplasma trifolii)引起的。本研究的目的是评估两种柳树和柳树对巫婆扫帚结构中瘿瘤^的形态和生理反应。柳属物种对瘿瘤的形态反应（称为生物胁迫）表现为叶和芽的生长抑制。因此，与健康植物相比，叶面积和芽节间显着减少。生物应激可以诱导氧化应激，在本研究中观察到氧化应激在瘿组织中大量积累H ₂ O ₂。受感染组织中大量积累的 H ₂ O ₂损害了叶绿素 a 和蛋白质。尽管柳属物种诱导抗氧化剂过氧化氢酶、过氧化物酶、脯氨酸、花青素和酚类来清除活性氧(ROS)，但在瘿组织中观察到H ₂ O ₂的大量积累。总而言之，无论抗氧化剂是否因虫瘿引起的氧化应激而被激活，活性氧的积累都会损害光合装置和蛋白质。