1973 年 38 巻 4 号 p. 737-751
The paper deals with polysomaty in thirty nine species and varieties of Liliales, collected from different parts of India.
The polysomatic behaviour has been shown to involve the occurrence of struc-turally and numerically altered chromosome complements in the somatic tissue along with the normal complement. Aneuploid and polyploid variations as well as the zone of occurrence have been recorded.
It has been inferred that both non-disjunction as well as endomitotic reduplication involving all or a few chromosomes of the set are responsible for such poly-somaty. Evidences show that fragmentation and translocation are responsible for structural alterations.
Of the numerical and structural alterations, it has been deduced on the basis of the data, that the latter plays a more important role in the origin of new geno-types as compared to the former. Genes susceptible to minute change in cell en-vironmental balance are selected and maintained in this category of plants. Heterochromatic regions which are more susceptible to environmental effects are mostly involved in structural alterations.
The suggestion that the nucleo-cytoplasmic balance at the tissue rather than at the individual cell level is maintained in this category of plants, has been supported. Here, the absence of balance at the individual cell level is advantageous as it provides the basis for irregular chromosome behaviour and somatic mutation.