Abstract
Analysis of quiescent seed extracts of Phaseolus vulgaris cultivars found high activities of chitinase, N,N′-diacetylchitobiase and β-N-acetylhexosaminidase in whole seeds and their dissected organs (cotyledons, axis, and seed coat). Activities of these enzymes were compared in seeds of two cultivars phenotypically distinguishable by soft white (cv. Surattowonder) and hard brown (cv. Maisugata) seed coats. In both cultivars, chitinase activity was found high in all organs, chitobiase in the seed coat, and β-N-acetylhexosaminidase mainly in the axis. In terms of specific activity, all three enzymes were extraordinarily higher in extracts of seed coat than the others, specially referring to the cultivar Surattowonder. Although the cultivars showed in general similar distribution patterns of activities among their seed organs, the discrepancies found between them seem to be expressing intrinsic attributes of their seed coats. The relationship between the two cultivars, the enzyme activities measured and defense mechanisms are discussed.
