[Effects of arbuscular mycorrhizal fungi on growth and iron uptake of Poncirus trifoliata under different pH].
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 microM 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 and active 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.


CONCLUSIONS
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.
Wang
Mingyuan
M
Department of Bioengineering and Biotechnology, College of Chemical Engineering, Huaqiao University, Xiamen 361021, China. mywang@hqu.edu.cn
Xia
Renxue
R
D018533:Biomass; D005658:Fungi / Q000254:growth & development*; D006863:Hydrogen-Ion Concentration; D058085:Iron Compounds / Q000378:metabolism*; D038821:Mycorrhizae / Q000254:growth & development*; D018517:Plant Roots / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology; D032104:Poncirus / Q000737:chemistry / Q000254:growth & development* / Q000378:metabolism* / Q000382:microbiology; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology
D058085:Iron Compounds; D012987:Soil