Effects of Pyrocatechol on Some Metabolic Processes of Mature Sugar Beet (Beta vulgaris) Plants

Abstract

AbstractPyrocatechol (PC), 10‐2M, was applied to the foliage of mature plants of sugar beet (Beta vulgaris L.). Its effect on the activity of nitrate reductase, transaminase, invertase, phosphatases, sucrose synthetase, sucrose phosphate synthetase, and UDPG‐pyrophosphorylase were determined 7, 14, and 21 days after treatment. Significant reductions in the activity of nitrate reductase, transaminase, invertase, and phosphatases (including phenyl phosphatase, glucose‐1‐, glucose‐6‐, fructose‐6‐phosphatase, and adenosine triphosphatase) in the treated plants occurred. On the other hand, activities of the enzymes of sucrose biosynthesis, uridine, diphosphate glucose pyrophosphorylase (UDPG‐pyrophosphorylase), sucrose synthetase, and sucrose phosphate synthetase were significantly stimulated by the application of pyrocatechol. The results suggest that the growth inhibition following the application of PC to sugar beet plants may stem in part from an amino acid stress resulting from a PC‐induced decrement in nitrate reductase and transaminase activity. Its application also creates an enzymatic condition favorable for sucrose biosynthesis and storage.