Light micrograph (LM) showing conjugation in Spirogyra sp. green algae. In this image the male filament is empy and the female filament contains the zygospore. Conjugation is a form of sexual reproduction in which micronuclei are exchanged by direct cell-to-cell contact or by a bridge-like connection between two cells. Fixed and stained. Magnification 100x at 35mm.