镉与萘复合胁迫对红树植物白骨壤幼苗萌芽及生长的影响

为探讨白骨壤(Avicennia marina)幼苗对重金属镉(Cd)和多环芳烃萘(Nap)复合胁迫的响应,采用砂基栽培,对其幼苗的萌芽和生长进行了研究。结果表明,Cd、Nap复合胁迫对白骨壤萌芽的抑制效应较单一胁迫明显,胁迫前期幼苗成活率提高,胁迫后期则降低。胁迫栽培45 d,10 mg L~(–1)的Nap在叶形态、茎高及各器官生物量上能够减轻Cd胁迫的影响,但增强对根长的抑制作用,10 mg L~(–1) Nap-25 mg L~(–1) Cd处理的叶面积、叶长、叶宽、茎高及全株生物量分别比25 mg L~(–1) Cd处理的提高9.6%、7.9%、7.4%、5.1%和20.2%,但根长则比150 mg L~(–1) Cd处理的下降11.1%。至胁迫栽培90 d,各处理间幼苗器官及全株生物量无显著影响,复合胁迫对叶形态、茎高和根长等的抑制作用要强于单一Cd胁迫。因此,随着复合胁迫时间的延长,Cd和Nap对白骨壤幼苗的生长由拮抗效应转变为协同效应。

Effects of Cadmium and Naphthalene on Germination and Growth of Seedlings of Mangrove Plant Avicennia marina

In order to understand the response to combined stresses of cadmium (Cd) and naphthalene (Nap), the germination and growth of mangrove plant Avicennia marina seedlings were studied cultured on sand in greenhouse. The results showed that the inhibition effect of seedling germination under Cd-Nap combined stress was more obvious than that under Cd stress. The survival rate increased at early stress stage, and then decreased at later stress stage. After cultured for 45 days, the inhibition effect of Cd on leaf size, stem height and biomass relieved treated with 10 mg L^-1 Nap, while inhibition effect on root growth enhanced. Compared to treatment with 25 mg L^-1 Cd, the area, length, width of leaf, stem height and biomass treated with 10 mg L^-1 Nap-25 mg L^-1 Cd increased by 9.6%, 7.9%, 7.4%, 5.1% and 20.2%, respectively, while root length decreased by 11.1% compared to treatment with 150 mg L^-1 Cd. When cultured for 90 days, the inhibitive effect of Cd-Nap stress on leaf size, stem height and root growth was stronger than that of Cd stress, but there was no significant difference in biomass. Therefore, with extension of combined stress time, the antagonistic effect of Cd-Nap on A. marina seedling growth turned into synergistic effect.