不同禾本科作物与花生混作对花生根系质外体铁的累积和还原力的影响

采用土培盆栽方法模拟玉米/花生、大麦/花生、燕麦/花生、小麦/花生、高粱/花生5种种植方式,研究混作对花生根系质外体铁的累积和还原力的影响.结果表明,当花生与5种分泌植物铁载体能力不同的禾本科作物混作时,花生新叶叶色正常,而单作花生则表现出严重的缺铁黄化症状,混作花生各部位的含铁量明显增加.与麦类作物(大麦、燕麦、小麦)混作的花生其各部位铁含量高于与玉米、高粱混作的花生,说明麦类作物改善花生铁营养的能力强于玉米、高粱,而两个玉米品种之间的能力差异不大,这主要是由于麦类作物分泌植物铁载体能力高于玉米、高粱.在花生生长至第50、60和70d时,混作花生根系质外体铁含量也随着逐渐增加,并始终高于单作花生.同时,混作明显地提高了花生根际土壤有效铁的含量,花生根系还原力也逐步提高.混作花生逐渐提高的还原力和介质中不断供给的易被花生还原吸收的铁,在改善花生的铁营养方面起了重要的作用.

Effects of peanut mixed cropping with different gramineous plants on apoplast iron accumulation and reducing capacity of peanut.

The effects of peanut mixed cropping with five different gramineous plants on apoplast iron accumulation and reducing capacity of peanut were investigated by soil culture experiment. The results showed that mixed cropping of maize, barley, oats, wheat, and sorghum with peanut could improve iron nutrition of peanut respectively. The phytosiderophores excretion rate of barley, oats and wheat were much higher than that of maize, and the phytosiderophores excretion rate of sorghum was lower than that of maize. In comparison with peanut in monocropping, the iron content in different organs of peanut mixed with maize, barley, oats, wheat and sorghum were increased. The Fe content in root apoplast of peanut mixed with five different gramineous was gradually increased and higher than that of peanut in monocropping at different growth days. At the same time, the mixed cropping systems remarkably improved the soil Fe availability in the rhizosphere and root Fe reducing capacity of peanut. The higher root Fe (Ⅲ) reducing capacity and much more available Fe in the rhizospe (Ⅲ) of peanut in mixed cropping played an important role in improving iron nutrition of peanut.