MEASUREMENT IN SITU OF CHITINASE AND BETA-N-ACETYLGLUCOSAMINIDASE ACTIVITIES IN GERMINATING SEEDS OF PINUS SYLVESTRIS AND EUCALYPTUS PILULARIS

摘要

beta-N-Acetylglucosaminidase (EC 3.2.1.30), exo- and endochitinase (EC 3.2.1.14) activities in individual seeds and in different parts of individual young seedlings of Pinus sylvestris L. and Eucalyptus pilularis Sm. were studied in situ, using a novel method with fluorogenic 4-methylumbelliferyl substrates. Intact seeds of P. sylvestris had measurable beta-N-acetylglucosaminidase and endochitinase activities after permeabilization. Production of radicles by P. sylvestris seeds did not increase levels of these enzyme activities over those present at the rupture of the seed coats. Endochitinase activity was greater in the roots than in the cotyledons and stems. beta-N-acetylglucosaminidase activity did not differ between the component parts of P. sylvestris seedlings. E. pilularis seeds did not have detectable beta-N-acetylglucosaminidase and endochitinase activities until the seed coat ruptured and then activity was predominantly beta-N-acetylglucosaminidase. Endochitinase activity increased as the seedlings developed and was greatest in the roots. The roots of E. pilularis also contained the highest levels of beta-N-acetylglucosaminidase activity. The empty seed coats of both species had high levels of both beta-N-acetylglucosaminidase and endochitinase activities. On no occasion was exochitinase activity detected in either plant species. [References: 15]