菌根真菌在红壤中对柑桔吸收磷肥的研究

接种一种球囊霉 Glomus sp.编号 CC-1于红壤中,使酸桔和枳实生苗的根系感染形成泡囊丛枝内生菌根。应用放射性同位素~(32)P 标记的可溶性磷肥和难溶性磷肥来研究菌根真菌对柑桔吸收磷肥的作用。放射性宏观自显影和显微自显影表明菌根真菌加强了柑桔对两类磷肥的吸收。放射性测量和化学分析证明有菌根柑桔实生苗的地上部含磷量以及从红壤中和从肥料中吸收的磷量比无菌根的增多,有菌根实生苗的生长反应也较好。

THE EFFECT OF MYCORRHIZAL FUNGUS ON PHOSPHATE UPTAKE BY CITRUS IN RED EARTH

Inoculation with an endomyeorrhizal fungus (Glomus sp.CC-1)on roots of sunki (Citrus reticulata) and trifoliata orange (Poncirus trifoliata),which are the most useful rootstocks of Citrus in our country,was carried out in pot experiments.The soil used was an nutrient poor especial phosphate deficient red earth,sterilized by autoclave. Seedlings of either species were dealt with four treatments,including soluble and inso- luble phosphate fertilizer application and with or without mycorrhizal inoculation.Each treatment was replicated three pots,consisting of 9 seedlings.Both phosphate fertilizers were labelled with radioactive isotope ~(32)P to examine the absorption of phosphorus by Citrus plants. The present study was undertaken to determine the effects of mycorrhizal infection on P uptake by Citrus seedlings.Microautoradiographs clearly showed that ~(32)P was ta- ken up by hyphae of mycorrhizal fungus and was accumulated in arbuscles and vesicles, inside the roots.Macro-autoradiograph demonstrated that ~(32)P was translocated in shoots of mycorrhizal seedlings much more than it was in nonmycorrhizal seedlings.Phosphorus analysis and seediling growth response indicated that endomycorrhizae increased phos- phate absorption from fertilizer and from soil as well.