EFFECT OF WIND-SPEED ON LOSS OF WATER FROM NOSTOC FLAGELLIFORME COLONIES

The effects of wind speed on loss of water from N. flagelliforme colon ies were investigated indoors in an attempt to assess its ecological s ignificance in field. Wind enhanced the process of waterless; the half -time of desiccation at wind speeds of 2.0 and 3.4 m s(-1) was, respec tively, shortened to one-third and one-fifth at 20 degrees C and, to o ne-sixth and one-eighth at 27 degrees C that of still air. Photosynthe tic efficiency was not affected before the wet alga lost about 50% wat er.