Volume 63, Issue 1
January 1966, pages 1-45
pp 1-4 January 1966
pp 5-8 January 1966
pp 9-16 January 1966
Trace elements zinc, copper, manganese, molybdenum and cobalt have been shown to have varying effects on growth and trace element composition of the silkworm. Results indicate the important role of manganese in the normal metabolism of the insect. Cobalt has been shown to exert a very favourable effect on growth and silk yield.
pp 17-25 January 1966
Benzimidazole is toxic to silkworms due to its antagonistic action to purines. Cobalt and copper possess the capacity to reverse its toxicity because of their ability to form complexes with benzimidazole. For reasons unknown cobalt exerts a favourable effect in its free form rather than in the vitamin form on the insect growth.
pp 26-34 January 1966
M. gravelyi Southern exposed to heterosmotic media showed considerable toleration of reduced salinities ranging from 5‰ to 28‰. While the rate of mortality was only 3·3% in a salinity of 28‰, it was as high as 68·5% in 5‰, at the end of 96 hours. Compared with the rates of mortality of other polychaetes,viz., Glycera embranchiata, Onuphis eremita, Loimia medusa, Clynene insecta andDiopatra variabilis all taken from the Adayar estuary, and similarly subjected to stresses of heterosmotic media, the rates of mortality inMarphysa gravelyi Southern were considerably low emphasising the wide range of toleration of reduced salinities in this worm.
pp 35-45 January 1966
From the foregoing accounts, a logical conclusion emerges, that while pollen mitosis cannot replace the cytological studies based on pollen mother-cells and root-tips, more often than not, it forms an excellent adjunct to them.
Apart from the study of pollen nitosis there are many other very interesting problems in pollen cytology, about which we have no clear understanding. These pertain mostly to the problems of cytoplasmic gradient and differentiation within the pollen grain.