Embryological studies in Rotula aquatica lour

Abstract

Sporogeneses, development of gametophytes, endosperm and embryo has been described in Rotula aquatica Lour. The flowers are borne on few flowered terminal and subterminal racemes. The floral parts develop in an acropetal succession. The anther archesporium is in the form of a plate of four to five cells. A mature anther consists of four wall layers, the innermost of these is the secretory tapetum with multinucleate cells. The endothecium develops fibrillar thickenings at maturity. The microspore tetrads are of tetrahedral, decussate and isobilateral types. Pollen grains are shed at two-celled stage. The ovules are anatropous, unitegminal and tenuinucellar. The archesporium is hypodermal and cuts off a parietal cell. The megaspore tetrad is of linear type. The chalazal megaspore is functional but sometimes any one of the remaining megaspores may also enlarge. The embryo sac develops according to Polygonum type. An integumentary tapetum is differentiated at the four-nucleate stage of the embryo sac. Endosperm is cellular and Myosotis-type. Chalazal and micropylar haustoria are organized; the chalazal haustorium is more aggressive. Embryo development is of Chenopodiad type.