叶用油菜和孔雀草间作对植物生长和镉累积的影响

Effects of Intercropping of Brassica chinenesis L. and Tagetes patula L. on the Growth and Cadmium Accumulation of Plants

为揭示镉(Cd)低积累作物与超富集植物间作对Cd污染土壤安全利用和提取修复的作用,通过盆栽试验,将两种Cd累积能力不同的叶用油菜(Brassica chinenesis L.,低积累油菜华骏和普通油菜寒绿)与4种孔雀草(Tagetes patula L.,矮杆红花、矮杆黄花、高杆红花和高杆黄花)间作,研究间作措施对两类植物生长、光合作用参数、Cd累积以及土壤有效态Cd和可溶性有机碳(DOC)含量的影响.结果表明,与单作相比,间作后油菜生物量显著降低,孔雀草生物量显著升高.间作处理中油菜叶片的净光合速率、气孔导度、蒸腾速率较单作均显著降低.华骏与矮杆红花间作时,华骏地上部Cd含量较单作显著降低14.5%,矮秆红花地上部Cd含量显著增加36.5%;其余间作处理下油菜地上部Cd含量均显著升高或无显著变化,而孔雀草地上部Cd含量无显著变化.间作处理下,油菜地上部Cd累积量较单作处理显著降低,孔雀草地上部Cd累积量显著升高.间作处理下土壤Cd提取率与孔雀草单作处理无显著差异.油菜地上部Cd含量与土壤有效态Cd以及DOC含量分别呈极显著和显著的正相关关系.总之,Cd低积累油菜华骏与孔雀草矮杆红花间作组合表现最佳,在Cd污染菜地土壤的修复和安全利用中有较好的应用价值.

A pot experiment was conducted to reveal the effects of intercropping a low-cadmium(Cd)accumulating cultivar and a Cd hyperaccumulator on the safe utilization and phytoextraction of Cd-polluted soils.Two cultivars of Brassica chinensis L.(the low-Cd accumulating cultivar Huajun,and the common cultivar Hanlü),were intercropped with four cultivars of Tagetes patula L.(Dwarf Red,Dwarf Yellow,Tall Red,and Tall Yellow).We examined the biomass,photosynthetic characteristics,and Cd accumulation in the plants and available Cd content and dissolved organic carbon(DOC)content in the soils.The results show that under the intercropping treatments,the biomass of B.chinensis decreased significantly and those of T.patula increased significantly,compared with the monoculture treatments.When intercropped with T.patula,the net photosynthetic rate,stomatal conductance,and transpiration rate in the leaves of B.chinensis decreased significantly,compared with the monoculture treatments.When Huajun was intercropped with Dwarf Red,the shoot Cd content of Huajun significantly decreased by 14.5%,and that of Dwarf Red increased significantly by 36.5%compared with the monoculture.Under the other intercropping treatments,the shoot Cd content of B.chinensis increased significantly,or showed no significant change,and that of T.patula showed no significant change.Under the intercropping treatments,the total amount of Cd in the shoot of B.chinensis decreased significantly,and that of T.patula increased significantly,compared with the monoculture.There were no significant differences in the Cd extraction ratios between the intercropping treatments and the monoculture of T.patula.The shoot Cd content of B.chinensis was significantly correlated with soil available Cd content and DOC content(P<0.01 and P<0.05,respectively).In conclusion,the intercropping treatment of Huajun and Dwarf Red significantly reduced shoot Cd content in B.chinensis and increased that in T.patula,and it did not affect the Cd extraction ratio.This is suitable for the safe utilization and phytoextraction of Cd-polluted soils.