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  • Flowering  (2)
  • Fruiting  (2)
  • heavy metals  (2)
  • Allorhogas pyralophagus  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Plant ecology 63 (1985), S. 113-119 
    ISSN: 1573-5052
    Keywords: Flowering ; Fruiting ; Leafdrop ; Leaf flushing ; Kumaun Himalayan forest ; Phenology ; Shrub layer phenology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phenology of 49 shrub species in five forest types occurring along an altitudinal gradient (350–2150 m) in Kumaun Himalaya has been studied. The evergreen leaf-exchanging taxa accounted for nearly half of the species, the remaining half was nearly equally divided between an evergreen continual leaf drop type and deciduous taxa. The percentage of species with lengthy leaf drop increased with elevation and finally leveled off. At each site the maximum leaf drop period coincided with the warm dry period. Percentage of species with multiple leaf flushing was low for all forests. The degree of extended leafing decreased with increasing elevation along which summer dryness also decreased. Earliest leaf initiation was observed for evergreen continual leaf drop species, followed by evergreen leaf-exchanging, and deciduous types. For each forest, two peaks of flowering activity occurred, one during the warm dry period and the other in the warm wet period. The percentage of species with multiple flowering increased with increasing elevation. Nearly half of the species bore fleshy fruits. The mature fruit retention period for different forests ranged from about 2–3 months. The proportion of deciduous species was similar in trees and shrubs; leaf drop was common during the summer season for trees, while it was common during the winter season for shrubs; the proportion of species with multiple leafings was greater and leaf initiation earlier in shrubs than trees; and generally shrubs showed two flowering peaks and trees only one.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Plant ecology 60 (1985), S. 91-101 
    ISSN: 1573-5052
    Keywords: Flowering ; Forest ; Fruiting ; Kumaun Himalaya ; Leafdrop ; Leaf flushing ; Phenology ; Phenological activity level ; Treelayer phenology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phenology of tree components of natural forests occurring between 350 and 2150 m in Kumaun Himalaya is descibed. All forests had more evergreen than deciduous taxa. The degree of evergreenness increased with increasing elevation and decreasing summer dryness. For most species (including all dominants) concentrated leafdrop and simultaneous leafing occurred during the warm-dry period of the year. About half of the species showed multiple leafing. All species had a sharp flowering peak in April. Wet-season flowering was rare. Most of the species flowered synchronously. In the sal- (Shorea robusta) and pine (Pinus roxburghii) forests a single peak of fruit maturation occurred in summer, while in other forests there also was a secondary peak in autumn.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Water, air & soil pollution 102 (1998), S. 313-328 
    ISSN: 1573-2932
    Keywords: dredged sediment derived surface soils ; heavy metals ; sedimentdisposal site ; sequential extraction DTPA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The objective of this study was to characterise pollution with heavy metals in surface soils sampled at various dredged sediment disposal sites in the Flemish region (Belgium). The sites selected varied in the period since sediment disposal ceased and in current vegetation and land use. Total metal contents (Cd, Co, Cu, Fe, Mn, Ni, Pb, and Zn) in the surface soils varied widely. For some disposal sites Cd and Zn concentrations greatly exceeded reference values for clean soil. The distribution of the metals as determined by sequential extraction differed between elements, but was simular for all the soils. This suggested that metals in these sediment derived surface soils were accumulated and transformed in a similar way. Residual fractions were low compared to total contents (2 – 4% for Cd, 25% – 35% for Co, 7 – 18% for Mn, 4 – 22% for Zn, 12 – 41% for Ni, 11 – 42% for Pb, 20 – 45% for Cu, 〈 10% for Zn). High metal concentrations in the acid-extractable and reducible fractions may indicate pollution from anthropogenic sources. DTPA-extractable metals, which may be considered indicative of plant-available contents, were relatively high compared to the total contents. The relative extractability, expressed as the ratio of DTPA-extractable to total contents, decreased in the order Cd (38%) 〉 Cu (28%) = Zn (26%) 〉 Pb (13%) 〉 Ni (10%) 〉 Co (3%). Most of the sites studied would be of concern if they were used for agricultural activities. No trends in metal availability in the period following disposal were apparent from the data.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-2932
    Keywords: heavy metals ; leaching ; mobility ; surface runoff ; percolation ; rainfall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Heavy metals in dredged sedimentdisposal sites may be transported through runoff andpercolation. In the present study metal fluxes byrunoff and percolation were determined under simulatedrainfall at a slope of 19% and a rainfall intensityof approximately 40 mm h-1. These circumstancescorrespond to half the mean annual erosivity of rainunder Belgian weather conditions. Surface runoff andpercolating water samples were analysed for suspendedsolids, total dissolved carbon and Cd, Cr, Cu, Ni, Pb and Zn.Runoff rate and sediment yields were highest for asilt loam sediment, characterised by a low clay andorganic matter content. Metal concentrations in runoffand percolating water varied widely between thesediments studied and were related to the total metalcontent in the sediment. In runoff and percolatingwater from the contaminated sediments, metalconcentrations strongly exceeded the Netherlands Areference values for ground water quality. Very highmetal fluxes were observed for the recently oxidiseddredged sediment. Metal transport per unit surfacearea through percolating water was from two to morethan twenty times greater than that in surface runoff.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-8248
    Keywords: Allorhogas pyralophagus ; graminaceous borers ; parasitoid ; low temperature storage ; Allorhogas pyralophagus ; mineuses des graminées ; parasitoïde ; conservation à basse température
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Des études de tolérance au froid ont été réalisées sous conditions de laboratoire sur les cocons d'Allorhogas pyralophagus, parasitoïde mexicain des mineuses des graminées. Par conservation, le temps de développement (du cocon à l'apparition de l'adulte) pouvait être allongé de 2 à 6 fois. Cependant les cocons conservés durant plus de 14 jours à 2°C ne pouvaient pas survivre, tandis qu'à 5 et 10°C, 50% environ d'éclosion était enregistrée après 21 jours de conservation. Compte tenu de la survie et de la longévité de l'adulte, 10°C semblait être la température de conservation la plus favorable. La période de pré-émergence était aussi augmentée significativement en conservant les cocons, de 21 à 35 jours à cette température. Le sex-ratio des adultes éclos n'était pas affecté d'une façon significative par la conservation. La fécondité était affectée défavorablement dans tous les essais, excepté dans le cas de femelles émergeant de cocons conservés à 5°C durant 7 jours. La descendance des parasitoïdes issus de cocons conservés à 5 et 10°C durant 35 jours était uniquement mâle. Il ressort de l'étude présente que les cocons d'A. pyralophagus sont plus sensibles à la conservation à court terme.
    Notes: Abstract Cold tolerance studies were conducted under laboratory conditions for coccons ofAllorhogas pyralophagus Marsh, a Mexican parasitoid of graminaceous borers. By storage, developmental time (from cocoon to adult emergence) could be extended by 2 to 6 times. However, cocoons stored for more than 14 days at 2°C failed to survive, while at 5 and 10°C, about 50% emergence was recorded for upto 21 days of storage. With respect to survival and adult longevity, 10°C seemed to be the most suitable storage temperature. Pre-emergence period was also significantly increased by storing cocoons for 21 to 35 days at this temperature. Sex-ratio of emerging adults was not significantly affected by storage. Fecundity was adversely affected in all the treatments except in the case of females emerging from cocoons stored at 5°C for 7 days. The progeny of parasitoids which emerged from cocoons stored at 5 and 10°C for 35 days consisted of only males. It is clear from the present study thatA. pyralophagus cocoons are more amenable to short-term storage.
    Type of Medium: Electronic Resource
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