Experimental Study to Compare the Effect of X-ray on the Somatic Chromosomes of a Few Species of Monocotyledons

Abstract

Bulbs and rhizomes of Nothoscordum fragrans, Haemanthus kalbreyeri, Zephyranthes mesochloa, Colocasia antiquorum, Zingiber officinale and Curcuma amada were irradiated at dosages of 250r and 500r, and the effect of irradiation was noted.
2. After forty-eight hours following treatment, heavy fragmentation, formation of micronuclei, structural alteration of chromosomes, lagging, etc. were observed in a large number of cases.
3. Frequency of fragments were found to be higher in treatment with 500r than with 250r dosage. This shows that the cells at different phages of interkinetic condition, in these species, become differentially affected following irradiation. This is in contrast to the previous report obtained with bulbs of Allium cepa, where all the interkinetic cells were found to be homogeneous as regards their response to irradiation is concerned.
4. It has been suggested that at the time of treatment, certain resting cells were lying at the last phase of interkinetic condition, that is, in a state just prior to germination. The enzymatic activity of these cells, necessary for germination, was completed at the time of treatment and so their germination capacity was not inhibited. In other young resting cells, however, the germination capacity was checked temporarily.
5. Fragments were found to be persisting after several days following irradiation. In Nothoscordum fragrans, fragments persisted even upto 2496 hours or one hundred and four days. Instead of assuming that fragments can remain ununited for such a long period, it has been suggested that possibly these fragments have passed through several cell generations, being included at random in the daughter cells and are on their way to degeneration.