摘要:入侵种与本地种杂交可能会改变其某些性状，影响其生理生化过程，增强其对一些重金属的耐受性。镉是目前造成土壤污染的主要重金属元素之一，为探讨杂交是否能够增强植物对重金属镉的耐受性，采用培养皿滤纸法比较了不同浓度镉（0，10，40，80和120 mg/L）处理下瘤突苍耳（Xanthium strumarium）、苍耳（Xanthium sibiricum）及二者杂合体（X.strumarium♀×X.sibiricum♂，X.sibiricum♀×X.strumarium♂）种子萌发与幼苗生长情况。结果表明：1）入侵种瘤突苍耳与本地种苍耳之间存在杂交现象；2）镉促进了杂交瘤突苍耳（X.strumarium♀×X.sibiricum♂）种子的萌发，当镉浓度为80 mg/L时，其萌发率、发芽势、发芽指数最高；3）杂交瘤突苍耳在80、120 mg/L镉处理下根长和叶绿素含量低于瘤突苍耳，但子叶受到的氧化胁迫并未高于瘤突苍耳。研究结果显示，杂交有可能提高了瘤突苍耳在高浓度镉胁迫时对重金属镉的转运能力，幼苗根系吸收大量的镉并向上运输给子叶，导致根系生长受到抑制、子叶叶绿素含量下降，抗氧化酶系统可能在降低子叶氧化程度上发挥了作用。



Abstract:Hybridization of invasive plants with native plants may alter their traits and enhance their tolerance to some heavy metals by affecting their physiological and biochemical processes. Cadmium (Cd) is one of the main heavy metal elements currently causing soil pollution. To investigate whether hybridization can enhance the tolerance of plants to cadmium, we used a filter paper to compare germination and seedling growth of Xanthium strumarium, X. sibiricum, and their hybrids (X. strumarium♀×X. sibiricum♂ and X. sibiricum♀×X. strumarium♂) under different concentrations of Cd (0, 10, 40, 80, and 120 mg/L). The results showed that:1) hybrids of X. strumarium and X. sibiricum exist in nature; 2) Cd promotes the germination of seeds of X. strumarium♀×X. sibiricum♂; when the Cd concentration was 80 mg/L, the germination rate, germination potential, and germination index of X. strumarium♀×X. sibiricum♂ were the highest; 3) the root length and chlorophyll content of X. strumarium♀×X. sibiricum♂ were lower than those of X. strumarium under 80 mg/L and 120 mg/L Cd, but the oxidative stress of cotyledons of X. strumarium♀×X. sibiricum♂ was less than in X. strumarium. These results show that hybridization may increase the transport ability of Cd in X. strumarium under high concentration of Cd. The roots of the seedlings absorb a large amount of Cd and transport it up to the cotyledons, which leads to inhibition of root growth and decreased chlorophyll content of cotyledons. The antioxidant enzyme system may play an important role in reducing the degree of cotyledon oxidation.





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