• Volume 45, Issue 5

      May 1957,   pages  187-262

    • The nucleus of the living zygote ofSaccharomyces carlsbergensis

      T R Thyagarajan M K Subramaniam

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      1. The zygotes ofSaccharomyces carlsbergensis retain the shape assumed at the time of their origin by the fusion of two spores even after they have produced a few buds.

      2. The nucleus is visible in the zygotes on the 7th day after the introduction of spores into fresh wort. A nuclear membrane delimits the nucleus from the cytoplasm and encloses formed structures. The structure of the nucleus is identical in a zygote and its bud.

      3. Iodine-formaldehyde-acetic gives a life-like preservation of cell structures. After removal of the cytoplasmic basophilia by acid hydrolysis, staining with hæmatoxylin gives pictures of nuclear details comparable to that of the living nucleus. The Feulgen stained area is only a portion of the resting nucleus.

    • Studies on the anatomy of the sugarcane moth borers - II. External anatomy ofChilo tumidicostalis, the stem borer of sugarcane

      V D Puri

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    • Flower structure and anthesis in the genusAlysicarpus

      H K Shama Rao S Solomon

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      There are many species of forage value in the genusAlysicarpus.

      The optimum period for the flowers to bloom is between 9 and 11a.m., the optimum temperature and humidity required being 76·2 to 80·5° F. and 74 to 57 per cent., respectively. Flowering starts in the middle of August and continues for about two months. InA. longifolius, A. buplurifolius andA. vaginalis, flowering takes place in two flushes; the second flush being of considerably smaller duration than the first.

      Dehiscence of anthers commences when anthesis begin, and is completed when the flower is ready for tripping,i.e., between 9 and 10a.m.

      The stigma is receptive in all species studied, between 10 and 11a.m. The time required from blooming to closing of the several parts, is about two hours.

      In the speciesA. rugosus var.styracifolius, A. buplurifolius, andA. vaginalis, the surface of the stigma is in level with the surface of the anthers; whereas, inA. rugosus var.heyneanus—Types A, B and C,A. pubescens andA. longifolius, the style protrudes 1 mm. beyond the anther lobes. Self-pollination generally occurs in the species where the stigmatic surface is in level with the surface of the anthers, but the same is usually prevented in the species where the style protrudes well beyond the anther lobes.

    • On the influence of sulpha drugs in sugarcane

      M S Subba Rao R B Prasad K L Khanna

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      Influence of five sulpha drugs,viz., Sulphanilamide, Sulphadiazine, Sulphaguanidine, Sulphamerazine, and Sulphathiazol has been studied under pot culture conditions.

      Variations in growth exposition as influenced by these have been described with a critical discussion in the context of the latest available literature on the mechanism of these drugs.

      Further possible lines of work have been put forward.

    • “The atemoya”, a promising new annona hybrid

      Sohrab R Gandhi N Gopalkrishna

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      The hybridisation has resulted in the development of hybrid No. 2 which is a distinct improvement on either parent from the point of seedlessness and eating quality. It is also capable of yielding a fair crop of about 80 fruits annually (unaided by hand-pollination) which can considerably be raised by making cross-pollination possible between it andA. squamosa. This can be arranged by growing a few plants ofA. squamosa along with the plants of hybrid No. 2 in the same plantation.

      The poor setting of fruits generally observed in all hybrids confirm the observations of P. J. Wester that the flowers of atemoyas require to be cross-pollinated for setting a successful crop. According to Wester’s investigations carried out in Florida, U.S.A., the flowers of annonas are protogynous and entomophilous,i.e., the pistils of the flowers are receptive before the anthers have developed ripe pollen, cross-pollination being therefore necessary and some outside agency like insects being required to effect it.

      To overcome this problem of cross-pollination, adequate provision for keeping a sufficient number of bee-hives should be made for the mixed plantations of Atemoyas andA. squamosa, that may be planted in future.

      As the progeny raised from seed would not breed true to type, No. 2 hybrid should be further propagated either by layering or by inarch-grafting on the root-stocks ofA. squamosa orA. cherimolia.

    • Seed abortion inElymus-sitanion allopolyploids

      R D’Cruz

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