混种牛膝菊嫁接后代对生菜镉积累的影响

Effect of Intercropping with Grafting Offspring of Galinsoga parviflora on Cadmium Accumulation of Lettuce

采用盆栽试验,将两种生态型(农田和矿山)镉超富集植物牛膝菊进行正反嫁接:以矿山生态型牛膝菊为砧木(后代为矿砧)、农田生态型牛膝菊为接穗(后代为农穗)进行嫁接和以农田生态型牛膝菊为砧木(后代为农砧)、矿山生态型牛膝菊为接穗(后代为矿穗)进行嫁接,研究了混种两种生态型牛膝菊正反嫁接实生后代(农田、矿山、农砧、矿砧、农穗、矿穗)对生菜镉(Cd)积累的影响。结果表明:与生菜单种处理相比,只有混种农穗及矿穗处理不同程度提高了生菜根系及地上部分的生物量(其中,混种矿穗处理的生菜地上部分生物量最大,较生菜单种处理提高了10.98%),其他混种处理均抑制了生菜的生长。另外,混种农穗及矿穗处理显著提高了生菜叶片过氧化物酶(POD)及过氧化氢酶(CAT)活性,但对其超氧化物歧化酶(SOD)活性的影响不大。混种牛膝菊嫁接后代显著降低了生菜地上部分的Cd含量,且与矿穗混种处理的Cd含量最低,较生菜单种处理降低了29.18%。因此,生菜与矿穗混种,既能有效降低生菜可食用部位(地上部分)的Cd含量,还能促进其生长。

A pot experiment was conducted to study the effects of intercropping with positive and negative grafting offspring of two ecotypes(farmland and mining)of cadmium(Cd)hyperaccumulator plants Galinsoga parviflora on Cd accumulation of lettuce.The positive grafting:the rootstock was mining ecotype of G.parviflora(grafting offspring was defined as mining-rootstock)and the scion was farmland ecotype of G.parviflora(grafting offspring was defined as farmland-scion);the negative grafting:the rootstock was farmland ecotype of G.parviflora(grafting offspring was defined as farmland-rootstock)and the scion was mining ecotype of G.parviflora(grafting offspring was defined as mining-scion).The results showed that compared with the monoculture of lettuce,only farmland-scion and mining-scion increased the root and shoot biomasses of lettuce(intercropping with mining-scion had the maximum of shoot biomass,increased by 10.98%compared with the monoculture),but the other treatments inhibited the growth of lettuce.In addition,intercropping with farmland-scion and mining-scion also significantly improved POD and CAT activities but had no obvious effects on SOD activity of lettuce.Compared to the monoculture of lettuce,intercropping with grafting offspring of G.parviflora significantly reduced Cd contents in shoots of lettuce,and intercropping with mining-scion had the minimum content,reduced by 29.18%compared with the monoculture.Therefore,intercropping with mining-scion not only effectively reduced Cd contents in the edible parts(shoots)of lettuce,but also promoted the growth of lettuce.