Comparative Enzymic Studies of Sucrose Metabolism in the Taproots and Fibrous Roots of Beta vulgaris L

Comparative enzymic studies of sugar beet (Beta vulgaris L.) taproots and fibrous roots revealed differences in invertase (EC 3.2.1.26) and sucrose synthetase (EC 2.4.1.13) activity. Invertase activity of the two root forms differs with respect to specific activity, pH optimum, and enzyme solubility. Acid invertase (pH 4.5) in the taproot was restricted to the peripheral meristematic tissue which produces cells for both taproot and fibrous root growth. This finding supports the hypothesis that the enzyme regulates sucrose partitioning between the taproot and fibrous roots. A distinct alkaline invertase (pH 8.0) was detected in sucrose storage tissues of the taproot.