Showing papers by "North Eastern Hill University published in 1982"

Phenology of trees in a sub-tropical humid forest in North-Eastern India

Abstract: Phenological observations were made on 122 tree species in a subtropical humid seasonal forest in north-eastern India. The forest had a high proportion of evergreen compared to deciduous species. Leaf-fall of most of the tree species coincided with the dry season. Flushing started towards the end of the dry season for a majority of the tree species, the degree and period of leaflessness varying with the species. Leaf production in the overstorey species extended over a longer period compared to the understorey species. For most of the species, flowering coincided with leaflessness. Proportionately more overstorey species flowered during the dry season and wet season flowering was more characteristic of understorey species. A majority of the species produced fleshy fruits during the wet season. Fruits, produced during the dry season, were mostly dry.

Ethnobotanical studies in nagaland. I. medicinal plants

Abstract: This paper forms the first report of an ethnobotanical study in the state of Nagaland. Fifty-one medicinal plants used by the Aos tribe in Nagaland are reported. This list is not exhaustive as it is anticipated that many more such plants will be added after thorough botanical exploration and more detailed ethnobotanical studies.

Population dynamics of Eupatorium adenophorum Spreng. during secondary succession after slash and burn agriculture (jhum) in north eastern India

Abstract: Summary Eupatorium adenophorum Spreng. is an important weedy colonizer in early successional communities developing after slash and burn agriculture (jhum) at higher elevations of the north-eastern hill regions of India. The relative performance of this species in terms of fecundity and survivorship in successional plant communities has been worked out. A net population increase occurred through both vegetative and sexual reproduction in early successional fallows up to 6 years old, the increase being greatest in a 6-year fallow. Mortality of seedlings was high in 1- and 3-year fallows, low in a 6-year fallow but reached 100% in older fallows. Seedling mortality was maximal during the monsoon although some seedlings also died during winter as a result of drought and frost. Mortality of vegetative sprouts followed a similar pattern to that of seedlings. The reproductive potential was reduced with increasing age of the successional communities and in a 15-year fallow all individuals were non-reproductive. Since E. adenophorum is able to succeed only in fallows of less than 6 years, repeated short jhum cycles of 4–5 years have had the effect of arresting succession al the weedy stage. Resume La dynamique des populations de Eupatorium adenophorum Spreng. se developpant apres abattage et brulage (jhum) dans le nord-est de l'Inde Eupatorium adenophorum Spreng. est une mauvaise herbe qui colonise de facon importante les surfaces ou ont ete pratiques l'abattage et le brulage (jhum) sur les sommets les plus eleves des regions montagneuses du nord-est de l'Inde. Les performances de cette espece en terme de fecondite et d'aptitude au developpement ont eteetudiees dans des successions de communautes botaniques. Un developpement net de la population s'est produit par la multiplication vegetative et sexuee des la mise en jachere et pendant une periode de 6 ans, le developpement de la population etant le plus important la 6eme annee. La mortalite des plantules etait elevee dans la premiere et la 3eme annee. mais basse la 6eme annee: dans des jacheres plus anciennes, ellc pouvait atteindre 100%. Cette disparition des plantules etait maximale durant la mousson, bien que quelques individus aient disparu egalement durant I'hiver en raison du gel et de la secheresse. La mortalite des rejets aeriens a suivi le meme schema. Le potentiel de reproduction etait reduite an fur el a mesure que les communautes vieillissaient et. dans une jachere de 15 ans. tous les individus etaient steriles. En raison de l'aptitude de Eupatorium adenophorum Spreng. a se developper seulement dans des jacheres de moinsde 6 ans. des cycles courts repetes de jhum (4–5 ans) ont eu pour effet d'arreter le developpement des mauvaises herbes. Zusammenfassung Populationsdynamik von Eupatorium adenophorum Spreng. wahrend der sekundaren Sukzession nach Hack- und Brandfeldbau (Jhum) im Nordosten Indiens Eupalorium adenophorum Spreng. ist eine hedeu-tende Besiedlungspflanze in den ersten Sukzes-sionsgesellschaften nach Hack- und Brandfeld-bau (Jhum) in den hoheren Regionen der nor-dostlichen Berggebiete Indiens. Das Verhalten dieser Art hinsichtlich Fruchtbarkeit und Uberle-bensrate in Sukzessionsfolgen wurde erarbeitet. Die Population vermehrte sich sowohl vegetativ wie sexuell in den ersten bis zu 6 Jahre alten Sukzessionsbrachen. wobei die grosste Zunahme in einer sechsjahrigen Brache zu verzeichnen war. Die Keimlingsmortalitat war in den ein- und dreijiihrigen Brachen hoch und in einer sechsjah-rigen Brache niedrig; in iiiteren Brachen hetrug sie aber bis zu 100%. Die Keimlingsmortalitat war wahrend der Monsunzeit am hochsten. einige Keimlinge starben aber auch im Winter durch Trockenheit und Frost. Die Mortalitiit vegetativ gebildeter Sprosse entsprach in etwa dem der Keimlinge. Das Vermehrungspotential nahm mit zunehmendem Alter der Pflanzengesellschaften ab und in einer 15jahrigen Brache waren alle Individuen nicht mehr vermehrungsfahig. Da E. adenophorum sich nur in Brachen. die nicht alter als 6 Jahre sind weiterentwickeln kann. bewirkten 4–5jahrige Jhum-Folgen, dass die Flachen mit dieser Art verunkrautet blieben.

Vesicular arbuscular mycorrhiza in subtropical aquatic and marshy plant communities

Abstract: Occurrence of vesicular arbuscular mycorrhiza in five subtropical ponds, i.e., eutrophic (P1,P2 andP3), running water (P4), oligotrophic lake (P5) and marshy plant community (M) was studied. It was observed that the plants growing inP1,P5 andM habitats exhibited the vesicular mycorrhizal association, whereas the fungal association was lacking in plants ofP2,P3 andP4 ponds. The endogonaceous spore population was estimated from water and sediments of the different ponds and it, was found that endophytes in sediments are less in terrestrial habitats and completely absent from water samples. The bioassay studies revealed that plants without mycorrhizal association grew poorly and all the endophytes isolated could establish vesicular arbuscular mycorrhizal associations in pot cultures.

A study on seed population dynamics of three weedy species of Eupatorium

Abstract: Summary The data on seed population dynamics of three weedy species of Eupatorium, viz. E. adenophwrum Spreng., E. riparium Regel and E. odoratum L. have been presented and discussed in the paper. The seed production and seed populations in soil seed bank were estimated, and the fate of buried seeds in soil was followed over a 2-year period. All the three species of Eupatorium produced a large number of seeds. The seed production of E. riparium per unit area was higher than that of the other two species because of its high population density. In all the three species most of the seeds were found to be present in the top 2 cm of the soil. The viable seed population of the three species of Eupatorium declined exponentially alter their burial in soil showing almost similar mortality patterns. A large proportion of seeds of all the Eupatorium spp. remained under enforced dormancy during their burial in soil with only a small fraction exhibiting induced dormancy. The longevity of the buried seeds increased on account of the dormancy imposed on them. The loss of seeds through degeneration and/or decomposition was rather low. Resume Elude de ta dynamique dus populations de semences de trois especes d'Eupatorium Cet article traite des donnees sur la dynamique des populations de semences de trois espece d'Eupatorium, viz. E. adenophorum Spreng, E. riparium Regal, E. odoratum L. La production et les populations de graines dans le sol ont ete estimees et le devenir des graines enterrees a eteetudie sur une periode de 2 ans. Ces trois especes d'Eupatorium produisent un nombre considerable de semences. La production de graines d'Eupatorium riparium. par unite de surface, est plus importante que celle des deux autres especes en raison de la densite de population plus elevee des plantes elles-memes. Pour les trois especes, la majorite des graines se trouvent dans les 2 premiers cm du sol. La viabilite des semences de ces trois especes decline de facon exponentielle apres leur enfouissement dans le sol se caracterisant ainsi, toutes trois, par des mortalites considerables. Une grande proportion des graines des trois especes demeure en dormance prolongee pendant leur enfouissement dans le sol, seulement une petite fraction d'entre elles ayant une dormance induite. La longevite des graines enterrees augmente en fonction de la dormance qui leur est imposee. La perte des graines par degenerescence ou decomposition est assez faible. Zusammenfassung Eine Untersuchung uber die Populationsdynamik der Samen von drei Unkrautarten der Gattung Eupatorium Daten zur Populationsdynamik der Samen von drei Unkrautarten der Gattung Eupatorium: E. adenophorum Spreng., E. riparium Regel und E. odoratum L. werden dargestellt und besprochen. Die Samenproduktion und die Samenpopulationen in der Samenbank des Bodens wurden erfasst und das Schicksal im Boden vergrabener Samen 2 Jahre lang verfolgt. Die Samenproduktion von E. riparium. bezogen auf die Flache. war grosser als die der beiden anderen Arten, was auf seine hohe Poputationsdichte z.uruckzufuhren ist. Bei alien drei Arten. befanden sieh die meisten Samen in den obersten 2 cm des Bodens. Die Lebensfahigkeit der Samen im Boden nahm bei alien drei Arten in ahnlicher Weise exponentiell ab. Ein grosser Anteil der Samen unterlag, nach-dem die Samen im Boden vergraben wurden. einer erzwungenen Dormanz. und nur bei einem geringen Teil war eine induzierte Dormanz beobachten. Aufgrund der Dormanz erhohte sich bei den vergrabenen Samen ihre Lebensdauer entsprechend. Der Verlust an Samen dureh Degeneration und/oder Zersetzung war ziemlich gering.

Structure and function of a sub-tropical humid forest of Meghalaya I. Vegetation, biomass and its nutrients

Abstract: The peripheral disturbed zone of a 50-year old stand of the forest at Lailad was dominated byDendrocalamus hamiltonii, an early successional bamboo characteristic of a secondary successional fallow of not more than 20–25 years while the central undisturbed zone hadSchima wallichii, Castanopsis indica andShorea robusta as important components. The biomass of the forest was computed as 137×108 kg/ha of which 64.7% was in the central zone. The contribution by different species both in the central and peripheral zone of the forest was worked out. Linear relationship betweendbh/d 2 h and biomass was worked out for different species. The standing crop had: N, 953; P, 284; K, 600; Ca, 2281; and Mg, 450 kg/ha, of which 60% was in the central zone of the forest.

Scanning electron microscopic observations on the tegumental surfaces of two rumen flukes (Trematoda: Paramphistomata)

Abstract: The surface microtopography of Calicophoron papillosum (Stiles & Goldberger) and C. calicophorum (Fischoeder), inhabiting the rumen of sheep, has been studied by SEM. In C. papillosum, conspicuous transverse ridges encircle the mid-body, gradually lessening dorsally towards the posterior end. The general body surface is aspinose and smooth except for minute bead-like tubercles in the circumoral area. Two types of putative sensory structures—domed aciliate papillae and tegumental pits—are present. Their characteristic aggregation in certain regions and their distribution in other parts of the body is described. A unique pattern of ridges, confined only to the base of the genital papilla and the genital atrium, has been observed. In C. calicophorum, tegumental folds encircle the body, these are more numerous near the anterior end and fewer posteriorly. The oral area has numerous concentric folds with domed aciliate papillae; between or on the papillae are tegumental elevated pits from the centre of which a knob-like structure protrudes. These sensory structures occur to a lesser extent in the acctabular area.

Infrared and Raman spectroscopic studies of KHSO4 crystals

Abstract: The Raman spectra of KHSO4 single crystals in different geometries have been investigated in the 10–4000 cm−1 range at 300 K, 150 K and 120 K. The infrared spectra of polycrystalline KHSO4 have also been measured. An interpretation of these results consistent with the crystal structure and other information on this system is presented.

Laser Raman and infrared spectra of di-potassium tartrate hemi-hydrate

Abstract: An analysis of the Raman and infrared spectra of di-potassium tartrate hemi-hydrate (DKT), K2C4H4O6·½H2O, is reported. It has been inferred that the C4H4O ion and H2O molecule in a DKT crystal occupy points of C1 site symmetry. Various units of C4H4O ion/(H2O molecule) located at crystallographically distinguishable positions in this crystal do not appear to be different in their structure or the force fields governing their vibrational dynamics.

Adaptive significance of seed reserves in ray achenes ofGalinsoga parviflora Cav.

Abstract: Ray achenes ofGalinsoga parviflora Cav. are significantly heavier, higher in calorific value and contain more protien and carbohydrate than disc achenes. The ray achenes showed early and better germination from different sowing depths and the seedlings from these grew better under nutrient deficient conditions. The differential response of the 2 achenes has been attributed to differences in the seed reserves and has an adaptive significance.

Decomposition of bamboo (Dendrocalamus hamiltonii Nees.) leaflitter in relation to age of jhum fallows in Northeast India

Abstract: Litter bags, containing bamboo (Dendrocalamus hamiltonii Nees) leaf litter was used to compare the decomposition rates and microbial populations in litter under fallows of different ages The age of the fallows were 0,5 and 10 years All were developed after Jhum (shifting) cultivation

The effects of soil texture and moisture on reproductive strategies of Spergula arvensis L. and Plantago major L.

Abstract: Summary The reproductive strategies of two weeds, Spergula arvensis L. and Plantago major L., were studied in relation to soil texture and moisture regime. On sandy soil, daily watering gave greatest dry wt per plant in S. arivensis, while fortnightly watering gave the greatest in P. major. In P. major, seed production was increased with increased moisture stress in sandy soil, but not in garden soil when watered fortnightly. Conversely, S. arvensis showed a decrease in seed number with increasing moisture stress in both soil types. The reproductive effort of S. arvensis was much greater (26.2–63.1%) than P. major (2.3–9.2%). There was greater emphasis on reproduction by S. arvensis under both soil types and various moisture regimes while P. major was characterized by higher allocation to vegetative structures which may confer a competitive advantage by increasing its efficiency of resource capture. Thus, S. arvensis seems to be r-selected and P. major K-selected. The differences in the reproductive strategies of the two weeds are discussed with reference to the environmental conditions under which they grow in nature. Resume Effets de la texture et de l'humidite du sol sur les processus de reproduction de Spergula arvensis L. et Plantago major L. Les processus de reproduction de deux mauvaises herbes, Spergula arvensis L. et Plantago major L., onl ete etudies en relation avec la texture du sol et le regime hydrique. En sol sableux un apport d'eau journalier donne un poids sec maximum pour.S. arvensis alors que pour P. major cela se produit avec un apport d'eau bi-mensuel. Pour P. major la production de graines augmente avec I'humidite du sol sableux mais avec arrosage bi-mensuel, ceci ne se produit pas dans un sol de jardin. A I'inverse, S. arvensis montre une diminution de la production de graines lorsque I'humidite des deux types de sol augmente. L'intensite de la reproduction est plus grande pour S. arvensis (26.2–63.1%) que pour P. major (2.3–9.2%). Il y a de la part de S. arvensis une intensification des processus de reproduction dans les deux types de sol et dans les diverses regimes hydriques alors que P. major est caracterise par une intensification du developpement vegetatif qui peut lui conferer un avantage competitif dans l'utilisation des ressources du sol. Les differences existantes entre les processus de reproduction de ces deux mauvaises herbes sont discutees en faisant reference aux conditions d'environnement qui leur sont propres. Zusammenfassung Einfluss der Bodentextur und-feuchtigkeil auf die Reproduktionsstrategie von Spergula arvensis L. und Plantago major L. Die Reproduktionsstrategie von zwei Unkrautarten. Spergula arvensis L. und Plantago major L., wurde in Abhangigkeit von der Bodentextur und den Feuchtigkeitsverhaltnissen untersucht. Auf sandigem Boden wurde bei taglichem Giessen das grosste Trockengewicht je Pflanze durch S. arvensis erreicht, wahrend dies bei P. major bei vierzehntaglichem Giessen der Fall war. Auf sandigem Boden stieg bei P. major die Samenproduktion mit zunehmendem Wasserstress; in Gartenerde und vierzehntaglichem Giessen war das aber nicht der Fall. S. arvensis hingegen zeigte in beiden Bodenarten mit zunehmendem Wasser

Growth and reproductive strategies of two annual weeds as affected by soil nitrogen and density levels

Abstract: SUMMARY The growth and reproductive strategies of two weeds, Spergula arvensis L., a weed of croplands, and Plantago major L., a weed of wastelands and lawns, were studied in relation to two soil nitrogen and four population density levels. The dry matter yield under the various treatments revealed that S. arvensis is less sensitive to density increase than P. major. The dry matter allocation pattern with reference to reproductive allocation was, however, not appreciably modified by soil nitrogen or density levels in either of the species, though reproductive allocation was higher in S. arvensis than P. major. S. arvensis produced larger numbers of seeds in nitrogen-rich soil while P. major did not. The results indicate that S. arvensis is more of an ‘r-’ strategist and P. major is ‘K-’ selected in the r-K continuum. In the C-S-R strategy model (sensu Grime), P. major may be assigned a position more towards ‘C’ and S. arvensis more towards ‘R’.

Population regulation ofEupatorium adenophorum spreng. andE. riparium regel: Effect of population density, soil nitrogen and light intensity

Abstract: Survival and growth of the two perennial ruderal weeds,Eupatorium adenophorum andE. riparium, was studied in relation to population density, soil nitrogen and light intensity. At high density, both the species showed some mortality which tended to increase with increase in soil nitrogen. Yield and seed production per plant ofE. adenophorum andE. riparium declined with increase in population density irrespective of soil nitrogen and light intensity. However, with increase in density, the yield and seed production per unit area ofE. riparium increased, while that ofE. adenophorum declined, indicating that the former species can absorb greater density stress whereas the latter is sensitive to crowding. Growth of both the weeds was favoured by soil nitrogen. Under low light intensity, the nitrogen requirement was presumably low, but under high light better growth was observed at increased soil nitrogen. Resource allocation pattern of the weeds was not affected by light intensity and population density. However, with increase in soil nitrogen, the allocation of biomass to roots declined while that to the reproductive structures increased.

Structure and function of a sub-tropical humid forest of meghalaya II. Litter dynamics and nutrient cycling

Abstract: The litter production in a 50 year old humid sub-tropical forest at Lailad was found to be 5.5 t/ha/yr, 77% of which was through leaf and the remainder through wood. Litter production was more in the peripheral disturbed zone compared to the undisturbed central zone which is related to the successional status of the community. Species differences in the rate of decomposition of litter was noted. Besides litter production and decomposition pattern were related to seasonal differences in temperature and humidity. The present results have been discussed in the light of the data from other studies done elswhere.

On some bood flukes (Spirorchiidae: Coeuritrematinae) from freshwater chelonians in India

Abstract: Coeuritrema sutlejensis Mehrotra, 1973 andC. sheilae arc described in detail and their validity is discussed. A key to the species ofCoeuritrema is provided and a few of the diagnostic features of the genus are emended.C. lyssimus Mehra, 1933 is recorded from a new locality and some variations from the original description are mentioned.

A study on biological activity measurements and heterotrophic bacteria in a small freshwater lake

Abstract: A 6-m-deep lake has been sampled to measure the temporal and depth-wise distribution of heterotrophic bacteria and biological activity in the water. Surface, mid-depth and bottom waters were analysed at monthly intervals for a period of one year. The coefficient of heterotrophic activity, alkaline phosphatase activity and biological oxygen demand are used as an index of biological activity. The bacterial community was at maximum during spring, coinciding with high values of biological activity. Highest biological activity was observed in the bottom waters. Dissolved organic carbon showed a significant positive correlation with most of the biological activity parameters. This suggests that biological activity, as measured by the coefficient of heterotrophic activity, was more closely related to the concentration of substrates than to population density of heterotrophic bacteria.

Kinetics and mechanism of the oxidation of halotoluenes by acidic hexacyanoferrate(III)

Abstract: The oxidation of halotoluenes by hexacyanoferrate(III) in aqueous acetic acid containing perchloric acid (0.5M) at 50°C gave the corresponding aldehyde as the major product, and a small amount of polymeric material. The order with respect to each of the reactants—substrate, oxidant, and acid—was found to be unity. Increasing proportions of acetic acid increased the rate of the reaction. The reaction was influenced by changes in temperature, and the activation parameters have been evaluated. The Hammett plot yielded a ρ+ value of −1.8. A kinetic isotope effect kH/kD = 6.0 has been observed. The pathway for the conversion of the halotoluenes to the products has been mechanistically visualized as proceeding through the benzylic radical intermediate, formed in the rate-determining step of the reaction. The radical undergoes rapid conversion to the products.

Seed germination and seedling establishment of two closely relatedSchima species

Abstract: Seed germination ofS. khasiana from Upper Shillong andS. wallichii from Shillong, Umsaw and Burnihat in Meghalaya, north-eastern India, and seedling establishment and growth of these species/populations in reciprocal cultivation were studied. Seeds lost viability and germinability gradually within a year when stored at 5 cm below the soil surface under natural conditions or at 20°C in the laboratory. Storage at 0°C permitted retention of 15–25% viability. Seeds germinated better on the surface layers (0–2 cm) of the soil.S. khasiana had a lower temperature optimum (15°C) of germination while the populations ofS. wallichii had a higher temperature optimum (20/25°C). At a temperature of 30°C, the lower altitude population ofS. wallichii from Burnihat gave higher germination than the high altitude population from Shillong. A given species/population ofSchima gave better seedling establishment and growth in its own natural habitat as compared to the introduced populations from the other altitudinal sites. This is indicative of the close adaptation of the natural populations to their habitat and ecotypic differentiation in this species.

A Convenient Method for the Synthesis of Alkali Metal Pentafluoromanganates(III)

Abstract: Reaction of MnO(OH) and a concentrated solution of AHF2 (A = NH4 +, Na+, K+ or Cs+) in 40% hydrofluoric acid gives instantaneously rose-pink coloured alkali metal pentafluoromanganate(III), A2MnF5 (A = NH4 + or Na+), and alkali metal pentafluoromanganate(III) monohydrate, A2MnF5.H2O (A = K+ or Cs+). Li2MnF5 has been synthesised by reacting lithium carbonate with a solution of MnO (OH) in 40% hydrofluoric acid followed by addition of a small amount of alcohol. Characterisation of the compounds and assignment of molecular structure were made from the elemental analyses, chemical determination of oxidation state of manganese in the compounds, magnetic susceptibility measurements and infra red spectral studies.

Synthesis of Tris(Acetylacetonato)Cheomium(III), Cr(C5H7O2)3

Abstract: Chromium(VI) oxide, CrO3, reacts with acetylacetone in the absence of any buffer readily giving a nearly quantitative yield of tris(acetylacetonato)chromium(III), Cr(C5H7O2)3. The compound has been characterised by chemical analysis, infrared and mass spectrometric studies. EI induced mass spectrometry showed the compound to be monomeric.