THE EFFECTS OF POPULATION DENSITY ON GAMETOPHYTE MORPHOGENESIS IN <i>POLYPODIUM VULGARE</i> L.

Abstract

S ummary Growth and development of gametophytes of Polypodium vulgare L. in culture are affected by population density. Increasing population density leads to an increase in gametophyte length and a delay in the transition to two‐dimensional growth. Cell number is at a maximum at an intermediate density. On the evidence presented it is concluded that the inhibition of development associated with high population density is attributable to the presence in the medium of a substance (or substances) secreted by the gametophytes. Although other explanations are possible, all the effects could be caused by a single, diffusible, volatile factor. It is suggested that the promotive effect of blue light on gametophyte development is due to the suppression of this factor by blue light.