Aluminum and pH limitations for germination and radicle growth of soybean

Effects of varying solution pH (3.75, 4.0, 4.5, 5.0 and 5.5) and Aluminum (Al) concentrations (0, 12, 21, 44, 81 and 106 uM monomeric Al, at pH 4.5) on the germination and radicle growth of soybean (Glycine max L.) cv. Fitzroy were studied on filter papers moistened with the treatment solutions. At 72 hours, germination was ≽ 85 percent at pH ≽ 4.5, but decreased to 73 percent at pH 4.0 and 53 percent at pH 3.75. Radicle length was not affected by pH in the range 4.0 to 5.5, but decreased significantly at pH 3.75 (Relative radicle length = 70 percent). Neither germination percent nor radicle length, at 72 hours, was influenced by varying Al concentrations (0 to 106 µM monomeric Al) at pH 4.5. While comparing the results of this study with those of our previous studies revealed that root growth was more sensitive to pH and Al limitations than either germination or initial radicle growth

Effects of aluminium on tap-root elongation of soybean (Glycine max), cowpea (Vigna unguiculata) and green gram (Vigna radiata) grown in the presence of organic acids

The role of fulvic, malic, and oxalic acids in alleviating the toxic effects of aluminium (Al) on tap-root elongation of soybean cv. Fitzroy, cowpea cv. Vita 4, and green gram cv. Berken was studied. Treatments consisted of a factorial combination of four Al concentrations (0, 12.5, 25 and 50 μM as Al(NO3)3·9H2O) and two concentrations either of malic or oxalic acid (0, 50 μM) or fulvic acid (0, 65 mg L-1 of organic carbon). The free monomeric Al in solution was determined using a pyrocatechol violet procedure which distinguishes between monomeric and organically complexed Al. Fulvic acid completely alleviated the toxic effect of Al at all concentrations on soybean and cowpea and at concentration