• Volume 97, Issue 5

      October 1987,   pages  365-442

    • Screening for powdery mildew (Erysiphae polygoni DC.) resistance in mungbean (Vigna radiata (L.) Wilczek) using excised leaves

      K S Reddy S E Pawar C R Bhatia

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      A simple, reliable method for assessing powdery mildew reaction on excised mungbean leaves has been developed and used for screening germplasm accessions. Third trifoliate leaves from 21–25 day old field-grown plants were cultured in enamel trays filled with tap water at 21±1°C, 12 h/day photoperiod (4136 lux/m2 from incandescent and white fluorescent light). After 9–12 days such leaves showed rooting from petiole and substantial root growth followed. Excised leaves could be maintained upto 40 days. Leaves were sprayed with conidial suspension (3·5×106 conidia/ml) of a local isolate of powdery mildew fungus. In susceptible types, powdery mildew lesions appeared 8–10 days after inoculation, enlarged and coalesced to cover the entire leaf area in 20 days. Fifty five germplasm accessions were tested using this method; all except 7 RUM accessions were susceptible. These RUM accessions showed resistant reaction even after two reinoculations. They were also resistant in the field under natural powdery mildew infection.

    • Cytology of hybrids betweenSolanum nigrum L. andSolanum furcatum Dun.

      A Ganapathi G R Rao

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      Cytomorphological features of theSolanum nigrum L. andSolanum furcatum Dun., and their F1 hybrids were studied. The hybrids showed highly irregular meiosis and were sterile without fruit-set. It is concluded that the morphological diversity and intersterility of the species are due to structural differences between their chromosomes.

    • Correlated changes in carbohydrate levels and associated enzyme activities during development and senescence of ray florets inChrysanthemum

      P Pardha Saradhi H Y Mohan Ram

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      Changes in fresh and dry weight, content of sugars and starch and activities of α-amylase and acid invertase were determined during various stages of ray floret development and senescence inChrysanthemum. Total and reducing sugars increased until the ray florets attained their maximal expansion, peak fresh and dry weights. This coincided with the highest activity of invertase. Starch content and maximal activity of α-amylase declined much earlier. It is presumed that invertase rather than α-amylase plays a major role in the expansion of ray florets inChrysanthemum. Senescing stages of ray floret are characterized by decrease in fresh and dry weights and loss of metabolites and a marked decline in the activities of both invertase and α-amylase.

    • Morpho-taxonomy ofAnthoceros crispulus (Mont.) Douin from south India

      S C Srivastava A K Asthana

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      Anthoceros crispulus (Mont.) Douin, with an extended distribution from plains of UP to montane areas in the Palni and Nilgiri hills in peninsular India, is characterized by radially lamellate (crispate) dorsal surface and lobed rosettes of thalli with stomata 44×33−56×44 μm, and inner lining layer cells of capsule wall with irregular thickening bands. Scanning electron microscopic studies of the spore provide additional taxonomic character as both proximal and distal faces are distinct in the sporoderm architecture.

    • Anatomy of three species ofBulbophyllum (Orchidaceae) with comments on their ecological adaptability and taxonomy

      P R Mohana Rao S M Khasim

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      Vegetative anatomy ofBulbophyllum andersonii, Bulbophyllum dyerianum andBulbophyllum leopardianum has been studied. Stomata are hypostomatic and cyclocytic with 4–7 subsidiary cells. Twin stomata occur inBulbophyllum dyerianum. Hypodermis is present only inBulbophyllum andersonii. InBulbophyllum dyerianum mesophyll is differentiated into palisade and spongy parenchyma, whereas in.Bulbophyllum andersonii it is less differentiated. InBulbophyllum leopardianum mesophyll is homogeneous. InBulbophyllum andersonii andBulbophyllum dyerianum columnar or club-shaped water storage cells with multispiral cellulosic thickenings are present in mesophyll of leaf and cortex of pseudobulb. In roots ofBulbophyllum dyerianum andBulbophyllum leopardianum fibrous mats are present. In all these taxa vessels are absent but vessel-like tracheids are abundant.Bulbophyllum species developed many adaptive characters for conservation of water. On the basis of anatomical data it is concluded that the genusBulbophyllum is closely related toDendrobium.

    • Effect of chemical composition on leaf-litter decomposition in forest soil

      S K Rout S R Gupta

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      Decomposition of leaf-litter of 3 tree species, two shrub species and a mixed-litter, derived from a mixed deciduous forest, was studied by measuring carbon dioxide evolution rates from soil. Predicted decomposition rates from total carbon dioxide production were correlated with various chemical constituents of the litters. Decomposition dynamics showed high initial rates for all the litter species. The overall decomposition per cent differed with the nature of plant species, being highest forGrewia (57·2%) and lowest forRhus (31·5%). The concentration of nitrogen, lignin, hydrogen and C∶N ratio had a major control on decomposition rates (r=0·92, −0·94, −0·98, −0·82,P<0·05 respectively).

    • Contribution to the embryology of mulberry (Morus alba var.Kanva-2)

      N K Dwivedi A K Sikdar M S Jolly N Suryanarayana B N Susheelamma

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      The anther development conforms to the monocotyledonous type. The tapetal cells are glandular and polynucleate. The pollen tetrads are of tetrahedral (68%), decussate (18%) and isobilateral (14%) types. The pollen grains are shed at 2-celled stage. The ovule is anatropous, crassinucellate and bitegmic. The development of embryo sac is of polygonum type. The endosperm is nuclear. The embryo development follows Urtica variation of Asterad type. The seed coat is 3 layered. The pericarp consists of 3 zones. The seed is endospermic.

    • Male sterile mutant inVigna radiata

      Kalpana Pande S S Raghuvanshi

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      Single and combined treatment of γ-rays and 0·25% EMS were tried onVigna radiata variety K851. A male sterile mutant was isolated in M2 generation. Experiments indicated male sterility to be recessive and monogenic in nature.

    • Sites of action of pyridazinone herbicides (SANDOZ 9785 and 9789) onChlorella protothecoides

      Karunyal Samuel Salil Bose

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      WhenChlorella protothecoides cells were grown in the presence of 30, 100 and 300 μM of SANDOZ 9785 and 9789, there was a significant decrease in cell number and packed cell volume as compared to control. SANDOZ 9789 seems to be a stronger inhibitor of growth than SANDOZ 9785. The immediate effect of pyridazinone herbicides on photosynthesis showed that SANDOZ 9789 is a weaker inhibitor than SANDOZ 9785. There was no direct correlation between the inhibition of growth and photosynthesis by the herbicide treatment suggesting that the inhibition of photosynthesis is not the primary cause of growth inhibition. Experiments on growth, carried out with non-photosynthetic and non green cells also support this suggestion. The observed increase in cell size when the cells grown with SANDOZ 9785 suggests that cell division was inhibited by SANDOZ 9785.

    • Numerical chemotaxonomy ofArachis

      S M J Anuradha G Nageshwar M Radhakrishnaiah L L Narayana

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      The chemotaxonomy ofArachis has been studied with reference to the distribution pattern of different classes of secondary metabolites in general and free amino acids and phenolic constituents in particular. The chemical data are quantified to bring out the relative primitiveness/advancement of the taxa. It is found thatArachis apressipila, Arachis cardenasii andArachis hypogaea are primitive andArachis stenosperma is advanced. The chemical data are further expressed in the form of different synthetic numerical indices and depicted in polygons which point out to a fair amount of relationship among the taxa studied. From the dendrogram of cluster analysis it is evident that the genus could be divided into two infrageneric groups.

    • Standing state and cycling of nitrogen in a Garhwal Himalayan grassland under grazing, burning and protection against herbage removal regimes

      Bina Agrawal S C Tiwari

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      The paper reports the standing state and cycling of nitrogen in 4 regimes viz. once-burnt, twice-burnt, open grazing and protection against herbage removal, in a submontane Garhwal Himalayan grassland. Protection against herbage removal increased average nitrogen content in plant material (shoot+root) over that in burning and open grazing regimes. The soil nitrogen (0–30 cm depth) increased with the frequency of fire. Protection regime had more bearing on the total annual nitrogen uptake by plants than fire and grazing regimes.

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