The Substitution of Complexing Substances for Boron in Plant Growth

Abstract

Mammoth Russian sunflower plants (Helianthus annuus) were supplied nutrient solutions, with B, without B but containing other complex-forming elements. Sr, Al, and particularly Ge, were found to alleviate B-deficiency symptoms temporarily and to increase growth of the seedlings significantly in the absence of B. These results provide evidence that the physiological role of B is likely related in part to the complexing property of the borate ion. On the basis of translocation studies utilizing C-14 sucrose and tests on the effects of sugar and citric acid applications to B-deficient plants, it does not appear that B is directly functional in sugar translocation because of the formation of a sugar-borate complex.