Abstract

Salix viminalis is a typical dioecious shrub willow, which has been widely used in the heavy metal polluted soil phytoremediation due to its fast growth rate, deep root system, and metal-resistance trait. It has been reported that dioecious plants present sex-specific characteristics when exposed to biotic and abiotic stress. However, different responses to heavy metal cadmium stress between male and female plants of S. viminalis have not been clarified. In this study, male and female S. viminalis clones were treated by 100 μM cadmium stress for a period of 21 days, and the root morphology, hydrogen peroxide content, malondialdehyde, and free proline content, antioxidant enzyme activities, and glutathione content were investigated after every 7-day interval. The results showed that female plants of S. viminalis developed thicker root diameter and volume and also accumulated more hydrogen peroxide than males at the first 7-day interval. Furthermore, sexual dichotomous indexes showed the most significant on the second 7-day interval. These findings suggest that male plants of S. viminalis have stronger cadmium tolerance than female plants and sexual differences in adaptive responses to cadmium are duration dependent, which adds to present evidence of sex-related responses to environmental stress in dioecious plants.

Novelty statement

Salix viminalis, a dioecious shrub willow, has been widely used in phytoremediation, yet sexually differences in tolerance to cadmium of which remained unclear. This study focused on different responses to cadmium stress between roots of male and female S. viminalis. Results show that male plants of S. viminalis have stronger cadmium tolerance than female plants, which indicates male S. viminalis should be more considered to be applied for phytoremediation and ecological restoration of cadmium-accumulated soil considering cadmium tolerance characteristics. The findings can provide valuable evidence and insights for researches focused on phytoremediation with dioecious woody plants and sexual dimorphism under abiotic stress.

中文翻译：

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镉胁迫下沙柳根系生长和抗氧化特性的性别差异

摘要

Salix viminalis是一种典型的雌雄异株灌木柳树，由于其生长速度快、根系深、抗金属等特点，被广泛应用于重金属污染土壤的植物修复。据报道，雌雄异株植物在受到生物和非生物胁迫时表现出性别特异性特征。然而，S. viminalis雄性和雌性植物对重金属镉胁迫的不同反应尚未阐明。在这项研究中，雄性和雌性S. viminalis用 100 μM 镉胁迫处理 21 天，每隔 7 天检查一次根系形态、过氧化氢含量、丙二醛和游离脯氨酸含量、抗氧化酶活性和谷胱甘肽含量。结果表明，S. viminalis 的雌性植物在前 7 天的间隔中比雄性植物的根直径和体积更粗，并且积累了更多的过氧化氢。此外，性别二分类指数在第二个 7 天间隔内显示最显着。这些发现表明S. viminalis 的雄性植物 具有比雌性植物更强的镉耐受性，并且对镉的适应性反应的性别差异取决于持续时间，这增加了雌雄异株植物对环境压力的性别相关反应的证据。

新颖性声明

Salix viminalis是一种雌雄异株的灌木柳树，已广泛用于植物修复，但对镉耐受性的性别差异仍不清楚。本研究重点研究了雄性和雌性长囊藻根对镉胁迫的不同反应。结果表明，S. viminalis雄株对镉的耐受性强于雌株，说明考虑到镉的耐受特性，应更多地考虑将雄性S. viminalis应用于积镉土壤的植物修复和生态修复。这些发现可以为专注于雌雄异株木本植物修复和非生物胁迫下的性二态性的研究提供有价值的证据和见解。