A Comparative Study in Umbellifers of Artificially Induced Polyploids and Structural Hybridity with Special Reference to Change in the Expression of Gene (Genes) Controlling the Pollen Shapes

The paper deals with a comparative data of cytological and palynological salient features of chemically induced autoploids and translocation heterozygotes of certain members of Umbelliferae (Anethum graveolens, Coriandrum sativum, Foeniculum vulgare, Pimpinella monoecia, Carum copticum, Cuminum cyminum and Daucus carota). In general the plants exhibit low multivalent frequency. At diakinesis Carum copticum has no univalents and trivalents while Anethum graveolens shows complete absence of trivalents, the remaining four genera have all the expected configurations. A comparative idea of the cytological anomalies exhibited by the plants understudy is also provided. A feature shared by all the plants investigated is the presence of nondividing pollen mother cells in their sporogenous tissue. The pollen of all the polyploids and some 2n treated plants show variability in shape while that of the controls is uniformly bipolar, radiosymmetric-characteristic of the family. The variable grains have been classified into definite types. Explanation has been put forward regarding this artificial induction of pollen variability and a scheme of the lines of development of the different shapes is also presented.