• Volume 22, Issue 2

      August 1945,   pages  31-86

    • Observations on the seasonal distribution of the plankton of the Trivandrum coast

      M A S Menon

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      An account of the general quantitative and qualitative study of the plankton of the Trivandrum coast during the years July 1938 to June 1940 is given with intensity charts and tables.

      The plankton productivity of this coast is found to be affected mainly by the monsoons when the organic and inorganic matter brought down into the coastal waters through the Karamana river on the south and the Veli bar on the north of the Trivandrum beach is found to be of considerable importance in the maintenance of plant and animal life in the coastal waters.

      A regular succession in the maxima of the three main constituents of the plankton—namely, diatoms, dinoflagellates and copepods—is noticed year after year. The occurrence of a secondary diatom maximum during January to February followed by a distinct fall in March (Hornell and Nayudu, 1923), does not seem to be a characteristic feature of the plankton of this area though this fact has been well emphasised by the earlier workers on west coast plankton. This difference is to be attributed to the comparatively heavier showers during the north-east monsoon in Trivandrum and south Travancore than on the west coast further north, and also to the proximity of the Karamana river and the Veli lake which open into the coastal area surveyed.

      The inhibiting influence of certain forms of plankton organisms such as the Gymnodinians which constitute the so-called ‘red water’, the blue-green alga,Trichodesmium and diatoms likePleurosigma andThalassiosira on plankton distribution is suggested, and the general factors governing the zoo-phytoplankton relationship are discussed in the light of the observations made.

    • Studies on Hæmosporidia from Indian birds—Series II

      Mukundamurari Chakravarty Amiya Bhusan Kar

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    • Vegetative propagation ofPiper betle in the Central Provinces

      R P Asthana K A Mahmud

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      1. Out of the twelve cuttings from each vine the first three took comparatively a longer period for germination than the rest.

      2. Mortality due toPhytophthora parasitica var.piperina was highest in 5th to 12th cuttings, the least susceptible being the 3rd cutting.

      3. Highest rate of growth was observed in the first cutting with progressively lesser rate in the succeeding ones.

      4. Yield of leaves was greatest in the first three cuttings.

      5. Incidence of foot-rot disease was significantly minimised when only the first three cuttings from each vine were used for propagation.

    • The mode of action of potassium on unstriated muscle

      Inderjit Singh

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      1. The action of potassium, calcium and sodium suggest that they exist in the combined and free form in the unstriated muscle, they respectively determine the excitatory, inhibitory and tonic and viscous states in the muscle.

      2. One of the actions of potassium is due to its difference in concentration on the two sides of the muscle membrane. This is shown by the fact that the optimum concentration of potassium in the saline for excitability depends upon its concentration inside the fibres. For maximum excitability there is an optimum ratio of potassium on two sides of the muscle membrane.

      3. The second action of potassium is probably on the cell membrane as it is antagonised by calcium.

      4. A third action of potassium is probably on the muscle colloid as it affects the viscosity of the muscle.

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