• Volume 55, Issue 2

      February 1962,   pages  65-106

    • Chalcocites of garimanipenta area, Nellore District, Andhra Pradesh

      K Kameswara Rao C Mahadevan

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      In this paper a detailed account of physical and optical properties of the chalcocites of Garimanipenta area, Nellore District, Andhra Pradesh, has been given. The chemical analysis of the chalcocites has indicated an excess of sulphur in the composition. The X-ray powder data and the ore-microscopic studies have revealed the existence of chalcocite in both isometric and orthorhombic modifications, covellite associated with the isometric chalcocite and bornite. It is suggested from these studies that the copper ores have resulted from hydrothermal (hypogene) solutions.

    • Chromosome numbers in some Indian medicinal plants

      C Gajapathy

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      The present paper deals with the meiotic chromosome numbers of 12 taxa and their ploidy. The seven new genera investigated arePseudarthria viscida n=11,Uraria hamosa n=11,Calycopteris floribunda n=24,Adenostemma lavenia n=10,Synedrella nodiflora n=19,Ichnocarpus frutescens n=10,Wrightia tinctoria n=10. The five species studied areClematis gouriana n=8,Hibiscus furcatus n=64,Spilanthes acmella n=26,Cordia wallichii n=21. The chromosome numbers are recorded for the first time.

    • Respiration of some marine planktonic organisms

      P K Rajagopal

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    • Charcoal rot’ a new disease of ashgourd (Benincasa cerifera Savi.) caused byRhizoctonia bataticola (Taub.) Butl. [Macrophomina phaseoli (Maubl.) ashby]

      T K Ramachandra-Reddy

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      Rhizoctonia bataticola isolated from ashgourd produced sclerotia and pycnidia on this host and compares favourably with other isolates from different hosts. Cross-inoculation tests with two other cucurbitaceous hosts (melon and squash) indicated that ashgourd (Benincasa cerifera) is a new host forR. bataticola.

    • Chloride regulation in a freshwater fish,Cirrhina reba, under heterosmotic conditions and high temperature

      V R Selvarajan

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      The freshwater fish,Cirrhina reba, is acclimated to different salinities up to 50% sea-water and found to be stenohaline. Survival in 50% seawater is only 12 hours.

      Both tissue fluid chloride and blood choride increase with the increase of salinity of the medium.

      In 40% sea-water blood chloride shows an increase of 14% over the freshwater fish while tissue fluid chloride increases by 83%. But in 50% sea-water, which is lethal, blood chloride increases sharply while tissue fluid chloride is nearly double that in freshwater.

      Fish kept in distilled water for one day show a 17% decrease in blood chloride while chloride in tissue fluid remains unaltered.

      The results are discussed and it is suggested that part of the regulation consists in shifting some of the blood chloride to the tissue fluids. In 50% sea-water failure seems to be in the inability of the fish to pump out the excess chloride as fast as it enters.

      Acclimation to high temperature results in a slight decrease in chloride in the blood and tissue fluids.

    • Studies on sandal spike - Part II. Physiological significance of the disturbed iron balance in the spike disease of sandal (Santalum album Linn.)

      K Parthasarathi P S Rao

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      Chlorosis in spiked sandal leaves, as in the chlorotic eaves of other plants, is caused by a deficiency of iron. However, the deficiency appears to be not on account of reduced availability of this element in the soil, but a direct effect of the spike disease, since the soil iron content is normal and the pH of the soil is on the acid side (Table III). Like other chlorotic leaves,23, 27 the spiked sandal leaves show an increase of amino nitrogen,19 oxalic and malic acids,28 and a decrease in calcium content.8, 29 Thus chlorosis in sandal leaves, caused by spike-induced iron deficiency, bears resemblance to the chlorosis in other leaves which is caused by the reduced iron availability in soils.

      In spike-diseased plants there is a comparatively higher accumulation of iron in the roots than in the leaves, which suggests that probably the mechanism of translocation of iron in the plant is affected. The preponderance of iron over calcium in the spiked sandal roots, as evidenced by the much lower Ca/Fe ratio in them, seems to be responsible at least in part for the death of root ends and cessation of haustorial connections in the spiked sandal.

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