Cytological studies in some aquatic angiosperms

Abstract

The paper deals with the cytological investigation of eight taxa,viz., Hydrolea zeylanica Vahl (2n=24),Ipomoea aquatica Forsk. (2n=30, 2n=30+1),Ottelia alismoides Pers. (2n=22 and 33),Monochoria vaginalis Presl ex Kunth (2n=52),Eichhornia crassipes Solms (2n=32),Pistia stratiotes L. (2n=28),Limnophyton obtusifolium Miq. (2n=22) andAmmannia salicifolia Monti (2n=28) which were collected from the suburbs of Mysore. Of these, the chromosome numbers forHydrolea zeylanica andAmmannia salicifolia are newly reported. Karyomorphological studies have been made inHydrolea zeylanica, Ammannia salicifolia, Ipomoea aquatica, Ottelia alismoides, Eichhornia crassipes andLymnophyton obtusifolium. Mitotc studies ofOttelia alismoides reveal the occurrence of both diploid and triploid races. Of these, triploid number of 2n=33 is the first report. An extra small chromosome from somatic nuclei is also the first record inIpomoea aquatica. Further,Ottelia alismoides shows the occurrence of univalents, tetravalents and hexavalents, whileLimnophyton obtusifolium reveals the presence of chromatin bridge, fragment chromosome and micronuclei.