• Volume 37, Issue 3

      March 1953,   pages  83-129

    • Additions to fungi of Madras—XIV

      T S Ramakrishnan K V Srinivasan N V Sundaram

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    • Fungi imperfecti from Madras—IV

      C V Subramanian

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    • Observations on the anatomy of some of the convolvulaceæ

      M Sayeedud-Din

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      1. In all the species ofArgyreia, Ipomœa andQuamoclit,vascular bundles are bicollateral.

      2. Isolatedsecretory cells occur in most of the species. Sabnis (1921) found them inBreweria latifolia Benth.,Convolvulus glomeratus Chois. andIpomœa sindica Stapf. Mullan (1933 and 1936) has described such elements inIpomœa pes-caprœ Sweet. andI. aquatica Forsk.

      3. Cuticle is striated in some of the species investigated.

      4. In all the casesstomata are of the Rubiaceous type.

      5. Calcium oxalate occurs in the form ofclustered and small or largesolitary crystals.

      6. Theclothing hairs consist of two cells—a stalk-cell and a terminal cell. The former is seated either on a single epidermal cell or on a collection of epidermal cells.

      7. Glandular hairs occur in some of the species. They consist of a short unicellular stalk and a flat or spherical head which is divided by vertical walls into several cells.

      8. Ananomaly in the structure of the stem is revealed by the presence of bands of wood on the outer side of the intraxylary phloem inArgyreia.

    • Petrakomyces, A new genus of the sphæropsidales

      C V Subramanian K Ramakrishnan

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    • Early tension relaxation during contraction of unstriated muscle

      Inderjit Singh

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      1. Unstriated muscle relaxes a little prior to contraction, and the contraction curve dips below the starting level before it returns to normal; the former relaxation has been termed as LR and the latter, AR. Properties of LR, AR and adrenaline inhibition have been studied.

      2. LR, AR and adrenaline inhibition require an optimum length for their production.

      3. The optimum temperature for LR, AR and adrenaline inhibition is about 25° C.; higher temperature cause inactivation.

      4. Previous activity decreases LR, AR and adrenaline inhibition.

      5. Iodoacetic acid decreases LR, AR and adrenaline inhibition.

      6. Sodium cyanide abolishes the peak tension, but increases inhibition,

      7. LR, AR and adrenaline inhibition decrease in the absence of calcium ions; excess of calcium at first increases and then decreases these relaxations.

      8. Increase in hydrogen-ion concentration from pH 8 to 6, decreases LR, AR and adrenaline inhibition.

      9. Potassium at first increases and then decreases LR, AR and adrenaline inhibition.

      10. Nitrate at first increases and then decreases LR, AR and adrenaline inhibition.

      11. It is concluded that LR and AR are identical with inhibition and are produced by relaxation of muscle fibres.

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