Volume 33, Issue 4
April 1951, pages 165-230
pp 165-177 April 1951
A comparative study of the contractile mechanism of frog’s, dog’s andMytilus muscles has been made.
Sodium and potassium chlorides have identical action on the three kinds of muscles. Barium chloride and sodium cyanide cause contraction of the contractile mechanism of unstriated muscle ofMytilus and elongation of frog’s and dog’s muscle.
Contraction of the contractile mechanism of unstriated muscle are of two kinds. One kind is relaxed by swelling of the muscle and the other kind not. Relation of this finding to the tonus mechanism is discussed.
Action of ammonium, calcium, strontium, magnesium, bromide, nitrate, iodide and thiocyanate is described. Potassium, magnesium relax the contractile mechanism.
The excitatory and the contractile mechanism of unstriated muscle have been dissociated by destroying the former by high voltages (110–880 volts A.C.) and by methyl alcohol. Action of substances on the contractile mechanism has then been studied.
If normal tone of the muscle is destroyed, then the asphyxiai contraction does not occur, proving the identity of the two.
pp 178-183 April 1951
pp 184-191 April 1951
pp 192-198 April 1951
The pollen grains are shed united together in quartets. Each pollen grain contains a generative and a tube nucleus. The tapetum remains uni-nucleate throughout. During the first metaphase, 24 bivalents have been counted.
The archesporium consists of three to four cells though only a single cell develops further. A parietal tissue of 4–5 cells in thickness is formed.
Megasporogenesis proceeds normally and the embryosac conforms to the monosporic eight-nucleate type. Synergids show the characteristic filiform apparatus and the polars may fuse before or during fertilization. Antipodals are formed as definite cells, and the degenerated remains may persist until fertilization.
Endosperm is free nuclear in the beginning and wall formation commences from the micropylar end stopping short of the lower one-third of the embryosac. The chalazal end contains free endosperm nuclei which aggregate simulating the basal apparatus with a tendency to grow into the chalazal region.
The first division of the fertilized egg is transverse while the second division which is vertical is belated in the upper cell. Later divisions are irregular and the embryo has no differentiated suspensor, being of the massive type.
In conclusion, grateful acknowledgements are made to Dr. L. S. Dorasami, M.Sc, Ph.D. (Lond.), Economic Botanist, for kind encouragement during the course of the work.
pp 199-203 April 1951
The vitamin D content of the six liver oils studied,viz., Khada Mushi, Waghbeer, Kan Mushi, Nali, Wagli and Surmai are found to be respectively 150·2, 140·7, 104·7, 108·2, 102·6 and 103·9 I.U. per gram of oil. The assay reveals that in comparison to their vitamin A content the vitamin D content is almost negligible, a finding which agrees with that of Ranganathan (loc. cit.) and Niyogi, Patwardhan and Acharya ((loc. cit.).
pp 204-220 April 1951
In view of the great technological importance of non-sugar constituents of juices in vacuum pan practice, an examination of their bearing on clarifying properties in the relatively inefficient open pan process was felt to be necessary in order to arrive at the optimum criteria required of varieties for the open pan industry. The work represents an attempt undertaken with the above end in view.
Certain relationships previously observed in this connection are confirmed.
Examination of some new aspects lead to the formulation of several other characteristics associated with superior clarifying properties and high quality of end product,viz.-
Low non-protein and high protein nitrogen contents.
Distribution of the total mineral content in such a manner that relatively smaller proportions occur in the colloidal fraction.
Low levels of soluble SiO2, Fe2O3 + A12O3 and CaO in juice.
pp 221-230 April 1951
Hormones of the spikes of wheat extracted at four different stages,viz., (a) Young spikes enclosed within the leaf-sheath, (b) Pre-anthesis (c) Anthesis, (d) Post-anthesis,i.e., 15 days after pollination, were injected into the leaves, of ages synchronising with the 4 stages of the plant.
The injections of the extracts at the first two stages did not bring about any significant difference in their respiratory activity. But the extracts at the two subsequent stages,viz., Anthesis and Post-anthesis had a marked effect; with this difference that the extract at stage 3 brought an immediate enhancement of the respiratory activity while at the 4th stage it reached its maximal at the end of 24 hours.
The hormone extract increases the hydrolysis facility of both the proteins and carbohydrates.