Volume 39, Issue 6
June 1954, pages 223-256
pp 223-235 June 1954
o| li]1.|Studies have been carried out on the effect of fluorine on the composition of bones of rats. Though no consistent variations have been observed in the Ca:P ratio of fluorosis bones, these have been found to contain less nitrogen, and more calcium, phosphorus, carbonate and sodium than the corresponding bones of the controls. In rats receiving 2 mgm. of NaF per day for 14 weeks, the magnesium content of the bones has not been found to be altered, whereas, it has been observed to decrease in the case of rats receiving 4 mgm. of NaF per day for 10 weeks. 2. These results have been further confirmed in the rats, placed on diet deficient in (i) nitrogen, (ii) calcium and phosphorus, and (iii) nitrogen, calcium and phosphorus. 3. The changes in composition have been observed in all bones. Though in some cases, the changes in the composition of scapulas and epiphyses are the most marked, it cannot be definitely stated that, in fluorine poisoning, these bones are most affected. 4. Calcium and phosphorus of the diet have been found to exert a protective action against the effect of fluorine on the composition of bones. 5. The data presented in regard to the carbonate and magnesium content of the experimental bones are in direct contrast to the findings of the earlier workers.1, 4,8, 11
The results are discussed in the second part of this piece of investigation.
pp 236-242 June 1954
Healthy young rats, 28 days old, were placed on six diets in one of which all the calcium was supplied entirely by skimmed milk. In the other diets half of the skimmed milk was replaced by enough ground dried leafy vegetables to provide the same amount of calcium as in the milk diet. At 60 days of age the animals were killed and their bodies analysed for calcium. Comparison of the availability of calcium in these vegetables with that of milk was made by calculating for each an utilization factor which is the ratio of calcium retention to intake. The values for the six diets were: 0·85 for milk diet, 0·74 for diet 1, 0·78 for diet 2, 0·79 for diet 3, 0·54 for diet 4, and 0.69 for diet 5 respectively.
All the five leafy vegetables,viz., Avati Keerai (Sesbania grandiflora), Mola Keerai (Amaranthus gangeticus), Chiru Keerai (Amaranthus spinosus), Curry leaves (Murraya Kænigii), Murunga Keerai (Moringa oleifera) form good sources of calcium from the point of nutrition, especially Avati Keerai, Mola Keerai and Chiru Keerai, as the calcium in these are used as well as that in milk.
pp 243-248 June 1954
Isolated leaves from seven different plants were treated with hormones in order to study their rooting response.
Ipomæa batatas leaves were treated with I.A.A., I.B.A. and N.A.A. and it was found that 2·5 p.p.m. I.B.A. is the best concentration for rooting.
Pogostemon leaves showed best rooting with 2·5 p.p.m. I.B.A.,Amaranthus with 5 p.p.m.,Helianthus, Chenopodium andBoerhaavia with 10 p.p.m. andCephalandra with 20 p.p.m. I.B.A.
Rooting response of various experimental leaves is different to different concentrations of the hormones.
It is suggested that the different rooting response of the materials to the different hormones lies on the structure of the cell wall and the reactive capacity of the hormones.
pp 249-256 June 1954
The floral parts arise in acropetal succession. Unicellular hairs are distributed over the floral parts. Plenty of tannin cells are found. The wall of the anther consists of five layers external to the tapetum. The tapetal cells are uninucleate at first, but later become binucleate, and are of the glandular type. The endothecium and the layer immediately below it are fibrillar. The microspores are arranged tetrahedrally, but occasionally show a decussate arrangement. The pollen grains have three and occasionally four pores and they are two-celled at the time of shedding.
The superior ovary is surrounded by a hypogynous disc. Three pendulous ovules arise from the mamelon, and project into the ovarian cavity around the central column.
The ovules are unitegmic, although this condition may not appear to be distinct during their subsequent growth, and they are tenuinucellate. At first they are hemianatropous, but later become anatropous.
A single archesporial cell functions directly as the megaspore mother cell. The development of the embryo sac conforms to the Allium type, and has been studied in detail. The embryo sac develops a cæcum within the ovule, which assumes a prominent haustorial function.