• Volume 86, Issue 3

      September 1977,   pages  143-209

    • Alachlor: A new potent antitranspirant on maize plants

      M Santakumari C S Reddy V S Rama Das

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      Foliar application of alachlor, 2-chloro-2-6-, diethyl-N-(methoxy methyl) acetanilide, at 20 mg/l on two-week-old plants ofZea mays L. produced remarkable partial inhibition of stomatal opening and significant reduction in the rate of transpiration. Antitranspirant activity of a single foliar application of alachlor persisted for twenty days after treatment. The rates of transpiration and apparent photosynthesis with alachlor treatment were compared with those of phenylmercuric acetate (PMA) treatments. Treatment with alachlor produced higher rates of photosynthesis, increased growth rate and yield, while PMA-treated plants exhibited a reverse trend. Alachlor thus proved to be an effective yield increasing antitranspirant under the experimental conditions used.

    • Studies on the soil fungi of Iraq

      A L S Ismail Samir K Abdullah

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      An investigation was carried out on soil fungi in the area around Basrah. Of the 37 species isolated, 3 belong to the phycomycetes, 32 to the fungi imperfecti and 2 to the Mycelia sterilia. In general, the mycoflora was found to be poor both with regard to the number of species and numbers of their propagules.

    • Cytomorphological studies in the genusHelianthus I. Karyotype studies in the diploid species

      R S Ramakanth A Seetharam

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      Karyotype of four 34 chromosome species ofHelianthus has been studied for the first time. The species differ very much morphologically with regard to several characters indicating considerable interspecific variation. Study of karyotype revealed wide range in their total chromosome length (260 to 140µ). Individual chromosomes are comparatively short with either median or sub-median centromere.H. annuus has a symmetrical karyotype with large number of median chromosomes whileH. debilis, H. argophyllus andH. lenticularis showed generally a tendency towards asymmetry. The species also differed with regard to number of chromosomes bearing secondary constriction.

    • Morphology, anatomy and development of the midrib galls on the leaflets ofLannea coramandelica (Hoult.) Merrill (Anacardiaceae) caused byOdinadiplosis odinae Mani (Diptera)

      A Raman C Devadas

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      A midge,Odinadiplosis odinae Mani induces galls along the midribs of the leaflets ofLannea coramandelica (Hoult.) Merr. (=Odina wodier Roxb.). Gall initiation takes place at a very early stage of leaf development, incited by the larvae from the superficially deposited eggs, migrating into the leaf tissue. Bulk of the gall is formed by the proliferation of the interfascicular or parenchymatous ground tissue. Vascular bundles occur widely separated and during the early stages of cecidogenesis, a few atypical tracheary elements appear which later develop into a very complex anastomosing network of vascular elements around the larval chamber with the maturation of the gall. The functional nutritive zone becomes sclerenchymatous with the ageing of the gall.

    • Studies on the development ofCommelina benghalensis L I. Zygote to globular proembryo

      K K Lakshmanan

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      The embryogeny ofCommelina benghalensis L, from zygote to the globular proembryo, is presented. The terminal cell of the proembryo, after two vertical divisions, right angles to each other, becomes morphogenetically differentiated: one of the half-hemispheres is destined to develop into the cotyledon and the other into the epicotyl. The subjacent tier—derivatives of the basal cell—which is close to the terminal tier, show two ontogenetic norms of development. The root pole is differentiated from the derivatives of the basal cell which are opposite to the shoot pole.

      The general outline of the proembryo as a whole becomes globular without any external morphological recognition into the cotyledon and epicotyl at the shoot pole. Nevertheless, the cotyledonary and epicotylary sectors of the terminal hemisphere lying adjacent to one another and occupying a truly terminal position on the embryonal axis, a position opposite to the root pole, can be recognised.

    • Some aspects of the morphology of the ovule and seed ofCostus malortieanus (Zingiberaceae)

      Jose K Mangaly K Sworrupanandan

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      The ovules ofCostus malortieanus are typically anatropous and are arranged along two lines on each septum, of the tricarpellary syncarpous inferior ovary. The ovular traces develop from the peripheral bundles of the axial vasculature. The ovule has a number of linear, translucent, multicellular appendages arising from the base and they are ontogenetically similar to ovular appendages in other Zingiberaceae. These appendages are derived partly from the funicle and partly from the free end of the outer integument; inC. malortieanus they are developed before anthesis and fertilization. The ovular appendages elongate considerably in the seed and entwine it irregularly. Seeds are more or less ovoid, compressed dorsiventrally and with the ventral surface highly wrinkled. It is concluded that the dual origin of the ovular appendages is a result of the anatropous nature of the ovule and may be of phylogenetic significance.

    • The aim and scope of plant morphology—I

      K Periasamy B G L Swamy

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      The study of plant form may be said to have four main aspects which are 1. verbal description of form, 2. classification of form, 3. genesis of form and 4. relation between form and function. While the first three aspects represent true and meaningful study of morphology, functional bias to morphology does not seem to have any purposeful validity.

      Goethe’s concept that the root, stem and leaf constituted the fundamental organs of the angiosperm plant body, was the principal source of pre-evolutionary ideas of formal morphology comprising modification of organs, axial and appendicular nature, and homology and analogy, all of which helped to integrate the mass of descriptive accounts of angiosperm morphology in a meaningful way. The advent of the theory of organic evolution, necessitated the explanation of the ideas of formal morphology in terms of the concepts of evolution. Although some of the ideas of formal morphology could lend themselves to this, the basic differences in their approach, scope and content are not easily reconcilable. Nevertheless, the superficial similarity between them has led post-evolutionary authors to mix these two more or less indiscriminately, and this has perhaps brought discredit to both.

    • Length-weight relationship of a carp,Labeo bata (Ham.)

      A Chatterji A Q Siddiqui A A Khan

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      The study of length-weight relationship ofLabeo bata (Ham.) revealed that this fish did not strictly follow the cube law and the weight increases at a rate more than the cube of the length. No significant difference was noticed in the value ofn by the analysis of covariance between the fishes of different size, sex and maturity stages in a population. The equations for length-weight relationship areW=0.2821×10−5 L3·3109 for the males,W=0·3388×10−5 L3·2026 for the females,W=0·2588×10−5 L3·3832 for the juveniles andW=04·893×10−5 L3·1667 for the combined fishes.

    • Oxygen consumption and ammonia excretion in the catfishMystus armatus, with special reference to swimming speed and ambient oxygen

      N Sukumaran M N Kutty

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      Oxygen consumption, ammonia excretion and ammonia quotient (AQ) (vol. NH3/vol.O2) in the catfish,Mystus armatus, acclimated to and tested in fresh water at 30°C, were obtained with special reference to swimming speed and ambient oxygen. At normoxia the fish maintained an AQ of about 0·12, while at low ambient oxygen (below 2 ppm) the AQ increased sharply to a value of 0·3 indicating an increase in protein metabolism of hypoxic conditions.Mystus armatus exercising continuously for 5 hr at various swimming speeds, utilized more proteins during the later phase of exercise. The increased protein utilization may be of advantage in maintaining acid-base balance and also in conserving sodium (Na+) in fish.

      In the recovery metabolism ofMystus armatus after hypoxic asphyxiation, the oxygen consumption showed a clearcut rise over the prehypoxic level, indicating that an oxygen debt was accumulating inMystus armatus exposed to hypoxia.

    • Sarcophaga ruficornis Fabr. (Sarcophagidae: Diptera) as a parasite of the common Indian toad

      Pranabesh Roy B Dasgupta

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      Laravae ofSarcophaga ruficornis (Sarcophagidae: Diptera) have been found to cause wound myiasis in toads (Bufo melanostictus) in Siliguri, West Bengal. Along with mechanical wounds on the body, the eyes and paratoid glands of the toads are also attacked, and at an early stage of infection these organs appear swollen. The larvae feed on the tissue of the toads for about 100 to 110 hr, and the pupal development period lasts for 9–10 days. Infected toads die in about 3 days.

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