Fig. 4.

The impact of hyperhydricity, as a result of poorly ventilated culture vessels, may promote shoot tip necrosis (STN). Schematic representation of the possible mechanisms involved in STN when an in vitro plant culture is established in a closed vessel, causing ethylene to accumulate (a). Schematic representation of the possible methods to reduce hyperhydricity and ethylene accumulation, by employing gas-permeable culture vessels, to ensure the healthy growth of shoot tips in vitro by reducing or eliminating the incidence of STN (b)