不同pH值下丛枝菌根真菌对枳生长及铁吸收的影响

Effects of arbuscular mycorrhizal fungi on growth and iron uptake of Poncirus trifoliata under different pH

【目的】本文对营养液不同pH值下丛枝菌根(arbuscular mycorrhiza)真菌地表球囊霉(Glomus versiforme)对枳[Poncirus trifoliata (L.) Raf.]实生苗生长及植株铁营养状况的影响进行了初步研究。【方法】采用盆栽砂培试验,分别施浇pH 5.0、6.0、7.0和8.0的霍格兰营养液(含50μM Fe-EDTA);常规方法测定植株生长指标;曲利苯蓝染色法测定菌根侵染率;分光光度法测定叶绿素含量和根系三价铁螯合物还原酶活性;原子吸收分光光度法测定叶片钾和活性铁含量;钒钼黄比色法测定磷含量。【结果】接种丛枝菌根真菌显著增加了枳实生苗的株高、茎粗、叶片数以及干样质量,明显促进了叶片叶绿素、活性铁和全铁含量,增强了枳根系三价铁螯合物还原酶活性,降低了叶片P/Fe以及50(10P+K)/Fe的比值;枳实生苗生物量、铁含量和根系三价铁螯合物还原酶活性在pH 6.0的处理中都是最高。【结论】接种丛枝菌根真菌能够一定程度上修复柑橘缺铁引起的黄化现象;4种pH水平中6.0是枳生长的最适pH值。

[Objective] We studied the effects of arbuscular mycorrhizal fungus（Glomus versiforme） on growth and iron uptake of trifoliate orange [Poncirus trifoliata（L.） Raf.] at different pH levels of nutrient solution.[Methods] P.trifoliata seedlings were grown in substrates watered by nutrient solution with 50 μM Feethylenediaminetetraacetic acid（EDTA） at pH values of 5.0,6.0（as control）,7.0 and 8.0 with a sand culture.Mycorrhizal colonization was tested by trypan blue staining method.Chlorophyll concentratration and root Fe （ Ⅲ ） chelate reductase activity were determined by spectrophotometer. Potassium andactive iron contents were quantified by atomic spectrometry, and phosphorus contents was through phospho-vanado- molybdate colorimetry. [ Results] The colonization of Glomus versiforme significantly increased the plant height, stem diameter, leaf numbers, and dry mass. Arbuscular mycorrhizal fungus significantly enhanced the accumulation of chlorophyll, active iron, total iron and root Fe（ Ⅲ ） chelate reductase activity, and decreased P/Fe and 50（ 10P ＋ K）/Fe ratios. All biomass, iron contents and root Fe（Ⅲ） chelate reductase activities of P. trifoliata seedlings at pH 6.0 level were the maximum both in inoculated and non- inoculated treatments. [ Conclusion] Arbuscular mycorrhizal fungi could remedy chlorosis caused by iron-deficiency in citrus, and 6.0 was the optimal pH value for the growth of P. trifoliata seedlings.