Some Observations on the Water-Relations of the Hyphae of Neurospora crassa

The morphology of the colony and of individual cells of thehyphae of Neurospora crassa are described. The behaviour ofthe hyphal apices in solutions of differing molarity is describedand this behaviour is related to the behaviour of Fusarium oxysporum.Measurements of the water potential of the apical cells aremade and it is shown that this corresponds to the balancing-pointin this fungus and in F. oxysporum. Measurements are then madeof the water potential of cells at various points along thelength of the hyphae, and of the osmotic potential of thesecells, and turgor pressure is calculated. The lowest turgorpressure of 12.4 atmospheres is shown by the apical cells andthe highest of 17.5 atmospheres by the basal cells. The validity of the methods used is discussed.