接种丛枝菌根真菌对雌雄美洲黑杨吸收铅镉的影响

以雌雄美洲黑杨(Populus deltoides)为研究对象,砂培条件下,研究接种丛枝菌根真菌(Glomus intraradices)对受Pb污染(200 mg·kg-1)、Cd污染(10 mg·kg-1)及复合污染的雌雄美洲黑杨Pb和Cd的富集与分配特征的影响,关注Pb/Cd复合污染独特的环境效应.结果表明:1未接种丛枝菌根真菌条件下,与单一污染相比,复合污染增加了美洲黑杨雄株叶、粗根、细根Pb和Cd含量;复合污染增加了雌株叶片中Pb和Cd含量,却降低了粗根和细根中Pb和Cd含量;复合污染条件下雄株Pb和Cd向地上部分器官的迁移率分别增加135%和78%,雌株则分别增加52%和18%.2复合污染条件下,接种丛枝菌根真菌引起雄株Pb和Cd富集系数分别增加87%和6%,雌株则分别增加171%和65%;雄株Pb和Cd向地上部分器官的迁移率降低65%和69%,雌株则分别降低59%和53%.3Pb污染条件下,接种丛枝菌根真菌的雌雄之间Pb积累量没有显著差异;Cd污染条件下,接种丛枝菌根真菌的雄株总Cd积累量是雌株的1.7倍;复合污染条件下,接种丛枝菌根真菌的雌株Pb和Cd总积累量分别是雄株的1.3和1.2倍.本研究表明,接种G.intraradices能提高美洲黑杨的Pb和Cd积累能力,对于不同污染条件下,应根据实际情况选择合适的杨树性别进行造林和生态修复.

Effects of arbuscular mycorrhizae fungi inoculation on absorption of Pb and Cd in females and males of Populus deltoides when exposed to Pb and Cd pollution

In this study, females and males of Populus deltoides were used as materials to study effects of Glomus intraradices on the accumulation and the allocation pattern of lead (Pb) and cadmium (Cd) when exposed to Pb pollution (200 mg·kg^-1), Cd pollution (10 mg·kg^-1), and their combination under sand culture. The interactive effects between Pb and Cd in the combined pollution were particularly emphasized. Results showed that under the sterile conditions, both Pb and Cd contents in leaves, coarse roots and fine roots of males increased under the combined pollution. However, in females, both Pb and Cd contents increased only in leaves but decreased in coarse roots and fine roots, in comparison with single pollution. The transfer index of Pb and Cd to above-ground organs increased by 135% and 78% in males and by 52% and 18% in females, respectively, under the combined pollution. Under the combined pollution, inoculation with G. intraradices increased both Pb and Cd enrichment index by 87% and 6% in males and by 171% and 65% in females, respectively, whereas decreased both Pb and Cd transfer index to above-ground organs by 65% and 69% in males and by 59% and 53% in females, respectively. Under single Pb pollution, there was no difference in Pb accumulation between the inoculated males and females, while under single Cd pollution, Cd accumulation in inoculated males was 1.7 fold more than that in inoculated females. Under the combined pollution, the Pb and Cd accumulation in females were 1.3 and 1.2 fold more than those in males, respectively. Therefore, our results indicated that symbiosis with G. intraradices could enhance enrichment of both Pb and Cd in P. deltoides. Under specific conditions contaminated by heavy metals, proper sex of P. deltoides should be considered for selection in the process of afforestation and ecological remediation according to the actual situation.