Volume 67, Issue 2
February 1968, pages 35-96
pp 35-53 February 1968
The paper reports for the first time the occurrence of eleven new species of Gastrotrichs in the interstitial sands of Waltair beach. Ten of these belong to the order Macrodasyoidea and the other to the order Chaetonotoidea. The distribution of these forms in relation to the size of the sand grains and depth has been described. The feeding habits and the other interstitial fauna associated with the Gastrotrichs have also been reported.
pp 54-60 February 1968
The paper deals with gametophytes ofEleocharis geniculata. Male archesporium is a file of 2 or 3-hypodermally placed cells. Anther wall is four-layered. Some cells of another epidermis are filled with tannin. Fibrous endothecium with usual structure develops from the hypodermis. Tapetum of the secretory type is developed. Its cells are uninucleate.
Pollen mother cells are polygonal in outline. Meiosis results in four haploid nuclei that later segregate as three non-functional and a functional nucleus. Septa are formed between them. The three effete nuclei are delimited by hyaline areas. After meiosis the cytoplasm of the pollen mother cell shows differential staining and soon pollen wall is thrown into folds. The folds are pronounced till the 2-celled stage of the pollen grain. Mature pollen grains are 3-celled at anthesis and show vacuolate cytoplasm with starch grains.
Female archesporium is generally a single cell. It cuts off a parietal cell which later forms a three-layered tissue. Megaspore tetrads are linear. The chalazal megaspore forms the Polygonum type of embryosac. Egg and synergids show normal structure. Secondary nucleus is centrally situated. The three ephemeral antipodals are housed in a chalazal pouch. Funicular obturator is developed.
pp 61-67 February 1968
The non-articulate, simple, feebly branched laticifers ofEuphorbia tirucalli, occurring in the stem and leaf, have been investigated. The young laticifers are multinucleate, thin-walled, and full of contents, while the older ones develop a secondary wall traversed by numerous, obliquely running pit-canals. A qualitative analysis of the latex shows presence of some carbohydrates, proteolytic enzymes, amylase, etc.
pp 68-76 February 1968
Soil samples from different parts of Southern India were examined for the presence of possible human pathogenic fungi, especially dermatophytes. A few species of fungi were isolated from certain soils, among which the dermatophyteMicrosporum gypseum was the most common. The dermatophytic fungi were generally found associated with soils surrounding human or animal dwellings, probably due to the presence in the environs of keratinaceous material.
pp 77-96 February 1968
The paper gives an account of the embryology of the genusPhoenix Linn. being intensively studied in this Department.Phoenix sylvestris Roxb. has been investigated as a type. Male and female flowers, pollen grains, development of ovule, male and female gametophytes, endosperm and embryo development were worked out.
The plants are dioeceous, 10–16 m. in height, with rough trunk due to persistent leaf bases. Both the inflorescences are spadix, each arising in the axil of a leaf in acropetal succession. There are 6–8 spadices at a time on a tree. The smooth and round pollen grains are shed in 2-celled condition. The ovules are anatropous, bitegmic and crassinucellate. The endosperm is nuclear to begin with but becomes cellular later.
The embryo develops according to theGeum variation of the Asterad type. It shows a definite tendency towards forming two cotyledons in early stages, but only one becomes massive later and attains maturity. The shoot apex is terminal. The micropyle shifts from terminal to lateral position. Besides this species,P. pusilla, P. robusta, P. acaulis andP. reclinata were also studied and they show the same pattern of embryo-sac and embryo development with certain variations.