TOWARD A CONTROLLABLE HEADSPACE COMPOSITION - GROWTH, DEVELOPMENT, AND HEADSPACE OF A MICROPROPAGATED PRUNUS ROOTSTOCK IN DIFFERENT CONTAINERS

The body and closure device of a tissue culture container are of param ount importance in the determination of the headspace composition, and influence plant growth and development. In fact, the container determ ines gas exchange with the environment quantitatively and qualitativel y. When exchange occurred via permeability, we demonstrated that a pro perly controlled container atmosphere (CA) cannot be obtained because accumulation and/or depletion of gases occur; modified atmosphere (MA) is then a better term. Our experiments also gave information about a) gas exchange mechanisms and b) the influence of headspace composition on plant growth and development. These are prerequisites for the unde rstanding and final control of the headspace composition. Three contai ners, differing in their gas exchange mechanism, were evaluated. This paper also considered that even under ''controlled'' culture condition s (container, environment, explant weight, etc.) variations from conta iner to container are registered, probably due to the explant itself.