A Development-Dependent Hemagglutinin from Cucumber Surfaces

During studies on the chemistry of plant surfaces, we observed that concomitant with the development of cucumber (Cucumis sativus L. cv ;ELEM') cotyledons an agglutinin that agglutinates human erythrocytes appeared on epicuticular surfaces. The agglutinin was released from cotyledon surfaces into distilled water by a 1-minute immersion (or even less). Homogenization of the washed cotyledons released residual agglutinating activity. The surface-located hemagglutinating activity was age-dependent and occurred in dark- and light-grown cotyledons. Agglutinating activities were present in light-grown cotyledons of 2- to 14-day-old seedlings and in dark-grown cotyledons of 3- to 17-day-old seedlings. Agglutinating activities were maximal in cotyledons of 3- to 4-day-old seedlings. No activity could be detected in dry seeds or in seedlings up to 2 days and after 17 days of germination. The hemagglutinating activity was specifically inhibited by N,N',N''-triacetylchitotriose, chitin, and chitosan.