Volume 36, Issue 5
November 1952, pages 181-223
pp 181-190 November 1952
Taking the nitrogen recovery as the criterian of. relative efficiency, amongst the organic manures F.Y.M., Compost, Activated sludgs and rape cake, rape cake proved to be the best manure for Rabi (wheat) while activated sludge generally gave higher nitrogen recoveries for kharif crops like jowar and maize. F.Y.M. and compost at 20 lb. N were ineffective while F.Y.M. at 60 lb. was as good as rape cake at 20 lb. The phosphate recovery was also highest in the case of rape cake treatment.
Addition of phosphate and potash to the organic manures had generally a depressing effect both on the course of nitrification of the manures and on the nitrogen intake by crops (except for the first jowar crop). This depression may be due to excessive potassium, the availability of which is already high in the soil and any further additions appear to be bearing both. This combination has consistently enhanced the phosphate intake by wheat.
Combination of organic and inorganic nitrogen along with the phosphate gave good recoveries of nitrogen for all crops (except maize) and during all the years. Phosphate recovery was also good with this combination in the case of wheat crop.
Complete artificials comprising of nitrogen, phosphate and potash gave good nitrogen recoveries in the beginning of the experiment but year by year the nitrogen recovery decreased.
Generally manures which nitrified most also gave the best nitrogen recoveries.
pp 191-197 November 1952
The wall of the young anther is made up of four layers of cells. The tapetal cells are binucleate and are of the glandular type. A stomium is organised at the line of dehiscence. The microspores are arranged in an isobilateral manner. The mature pollen grain is two-celled.
Septal nectaries are present on the ovary wall. The ovules are anatropous and bitegmic, and the micropyle is formed by the inner integument. A conducting strand consisting of a biseriate row of cells is seen at the chalazal end of the ovule and this connects the base of the embryo sac with the funicular strand.
The development of the embryo sac follows the Polygonum type. Double fertilisation is observed.
The endosperm is Helobial and its cells are full of starch.
The mature embryo is monocotyledonous. Only epidermal layer of the outer integument persists in the mature seed.
pp 198-214 November 1952
Studies in the physiology of phanerogamic parasitism with special reference toStriga lutea Lour. andS. Densiflora Benth. onAndropogon sorghum Hack. - II. The influence of temperature and moisture on the germination and growth ofS. lutea and S. densiflora
The relation of temperature to the germination ofS. lutea andS. densiflora seeds was determined. The temperatures tried were 30° C, 35° C. and a control at room temperatures which ranged between 20° and 30° C. The tests were carried out in petri-dishes containing one seed of a susceptible variety ofSorghum along with those of the parasite.
30° C. was found to be the optimum for 5.lutea and 35° C. forS. densiflora. Room temperatures were the next best forS. lutea and 30° C. forS. densiflora. 35° C. gave the lowest germination forS. lutea and room temperatures forS. densiflora. The germination ofS. densiflora at 35° C. was only 14·4% as against 46·9% ofS. lutea at 30° C. (its optimum).
The optimum temperatures for the maximum attack and growth ofS. lutea andS. densiflora have been determined by growing the parasites along with the hosts in cans placed in soil temperature tanks and on the glass-house bench.
The optimum moisture level of the soil for the attack and growth ofS. lutea andS. densiflora have been determined by growing the parasites along with the hosts in cans placed on the glass-house bench. The desired moisture level was maintained by a modification of the method adopted by Bailey (1940).
Constant temperatures of 35° C. induce the largest number ofS. lutea plants to attack a single host and theS. lutea plants make the fastest growth in height.
None of the three temperatures tried,viz., 35° C, 30° C. and uncontrolled (20°–40° C.) showed any significant differences in the number ofS. densiflora plants but in the last treatment theS. densiflora plants made the best growth.
30% Moisture level was the optimum for the maximum attack and growth ofS. lutea.
30% moisture level also gave the best results forS. densiflora but the differences between 30% and 25% were not significant. The differences between 30% and 20% were significant at 5% level only.
pp 215-222 November 1952
A Bethylid parasite was spotted on the larvae of woolly bear,A. vorax in May, 1950. Its life-history has been studied in detail at 87 ± 2° F./84 ± 8% R.H. A female parasite generally selects a medium-sized to full-grown larva and stings the latter on the ventral side of the thoracic region; The larva is thus paralysed and finally dies. Very young larvae which measure less than 1·733 mm.×0·707 mm. are killed by biting. The males live for about 5 days but the females live for 35 days. Sex ratio of female to male is nearly 2:1. Pre-oviposition, oviposition and post-oviposition periods have been observed to be 3, 31 and 4 days respectively. A female is capable of paralysing and killing on an average 159 larvae in her life-time. Of these only about 39 larvae are used for egg-laying. A female parasite lays 1–4 eggs (rarely 5) on a single paralysed host and in her life-time lays about 64 eggs. Eggs hatch within 2 days and the larvae pierce the body of the host and start feeding on the body fluid. Generally, three larvae are able to develop successfully into cocoons on one host. Larval period occupies about 6 days. The full-grown larva constructs a white silken cocoon and pupates inside. Pupal period occupies 21 days. Parthenogenesis occurs but the progeny are only males. Under laboratory conditions, the parasite attacks larvae ofAttagenus sp. in the absence of larvae ofA. vorax. So far no hyperparasite has been observed.
pp 223-223 November 1952 Erratum