Articles
POSSIBILITIES AND LIMITS OF MICROPROPAGATION IN RELATION TO VIRUS-FREEING IN ORNAMENTAL PLANTS
Some problems of meristem culture are discussed and the difficulties encountered in virus-freeing referred to, with the aid of examples from chrysanthemum, carnations, pelargoniums and freesias.
Only with heat therapy, meristem culture and testing combined in a closed circulation can satisfactory results be expected.
The in-vitro methods are compared with the traditional horticultural propagation methods and their efficiency limits discussed.
By example of freesias, the reasonable combination of virus-freeing through meristem culture and testing with subsequent in-vitro propagation is demonstrated.
The use of growth regulators in plant tissue culture has offered a number of new possibilities in floriculture.
Novel hybrids of species and genera have become practicable by surmounting pro- and post-gametic incompatibility barriers.
Thanks to callus culture, it is also possible to enhance genetic variability, furthermore, micropropagation is employed for the rapid, genetically identical propagation of valuable plants from root stocks of fruit trees or in the propagation of parental lines during hybrid cultivation (Leike et al., 1978).
As for phytopathology, three methods of tissue culture are of special interest inasmuch as it is concerned with virus-freeing vegetatively propagated cultures within the framework of maintaining selection.
First, there is the so-called meristem culture that enables differentiation of partially non-differentiated tissue through growth regulators; second, there are axillary buds stimulated by 6-benzyl aminopurine (BA) or the like; and third, there is the so-called callus culture with subsequent adventive organogenesis.
The last two methods allow a very fast vegetative in-vitro propagation.
The great potentialities of these three specialized fields of in-vitro culture have partly led to misinterpretations which can be rectified only step by step.