氮素形态和韧皮部烫伤对玉米韧皮部铁运输的影响
Effects of different nitrogen forms and phloem-scalding on iron transport in phloem of maize plants
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摘要: 用营养液培养方法研究了在不同供铁条件下不同形态N和韧皮部烫伤对玉米苗期韧皮部Fe运输的影响。结果表明,韧皮部烫伤提高了玉米根系Fe的再利用,降低了初生叶中Fe的再利用,尤其在缺Fe条件下这种作用更明显,提高和降低的幅度更大。韧皮部烫伤还降低了伤流总量,增加了Fe的浓度。在供应铵态N的条件下,Fe的韧皮部运输比供应硝态N条件下有显著增加,Fe的再利用明显提高。Abstract: The effects of different nitrogen forms on iron transport in phloem and reutilization in maize plants were studied by phloemblocking technique with solution culture under controlled conditions. The results showed that the scalding of phloem led to a decrease in biomass of root and new leaves and increase in biomass of primary leaves and stem, an increase in reutilization of Fe in roots and a decrease of Fe in primary leaves, especially for plants without Fe supply, an increase of weight of xylem sap and a decrease of its Fe concentration, and also for deficient Fe plants. The remobilization of Fe in root was enhanced by scalding for maize plants with NO3--N or NH4+-N. Irrespective of NO3--N, NH4+-N supply favors the transport of Fe in xylem and phloem of maize plants whether the phloem is scalded or not.