Home  About us  Contact
 

Environment Chambers (environment + chamber)

Distribution by Scientific Domains
Life Sciences75%

Kinds of Environment Chambers

  • controlled environment chamber
    		•

    Selected Abstracts

    Effect of Salt Stress on Carbon Metabolism and Bacteroid Respiration in Root Nodules of Common Bean (Phaseolus vulgaris L.)

    PLANT BIOLOGY, Issue 4 2000
    A. Ferri
    Abstract: In the present work, we examined the effect of salinity on growth, N fixation and carbon metabolism in the nodule cytosol and bacteroids of Phaseolus vulgaris, and measured the O2 consumption by bacteroids incubated with or without the addition of exogenous respiratory substrates. The aim was to ascertain whether the compounds that accumulate under salt stress can increase bacteroid respiration and whether this capacity changes in response to salinity in root nodules of Phaseolus vulgaris. The plants were grown in a controlled environment chamber, and 50, 100 mM or no NaCl (control) was added to the nutrient solution. Two harvests were made, at the vegetative growth period and at the beginning of the reproductive period. The enzyme activities in the nodule cytosol were reduced by the salt treatments, while in the bacteroid cytosol the enzyme activities increased at high salt concentrations at the first harvest and for ADH in all treatments. The data presented here confirm that succinate and malate are the preferred substrates for bacteroid respiration in common bean, but these bacteroids may also utilize glucose, either in control or under saline conditions. The addition of proline or lactate to the incubation medium significantly raised oxygen consumption in the bacteroids isolated from plants treated with salt. [source]

    Predatory effect of Coccinella septempunctata on Thrips tabaci and Trialeurodes vaporariorum

    JOURNAL OF APPLIED ENTOMOLOGY, Issue 5 2005
    P. N. Deligeorgidis
    Abstract:, The predatory effect of adult ladybird Coccinella septempunctata L. on adults of thrips, Thrips tabaci Lindeman, and whiteflies, Trialeurodes vaporariorum (Westwood), was examined in controlled environment chambers, on tomato leaves, in transparent small plastic cages at proportions of 1/(10 + 10), 1/(20 + 20), 1/(30 + 30) and 1/(40 + 40) predator/number of thrips and whiteflies. We conclude that C. septempunctata could be used with success for the biological control of thrips and whiteflies in greenhouse crops, with almost the same effectiveness as for aphids, at predator/prey proportions near 1 : 30. Additionally, it was found a prey preference for T. tabaci in comparison with T. vaporariorum. According to the model used, effective predation is correlated with predator/prey ratio rather than to prey preference. [source]

    The effect of drought stress and temperature on spread of barley yellow dwarf virus (BYDV)

    AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2000
    I. N. Smyrnioudis
    Summary 1 The effect of drought stress and temperature on the dispersal of wingless aphids Rhopalosiphum padi (L.) and the pattern of spread of BYDV (barley yellow dwarf virus) within wheat plants in controlled environment chambers was quantified. Combinations of three different drought stress levels, unstressed, moderate and high stress level, and three different temperatures, 5 ± 1 °C, 10 ± 1 °C, and 15 ± 1 °C, were investigated. 2 With increased temperature there was an increase in the mean distance of visited plants from the point of release and in the number of plants visited and infected with BYDV. Drought stress had no effect on mean distance moved by aphids at any temperature or on plants infected with virus at 10 °C and 5 °C. When plants were drought stressed, the numbers of plants visited and infected were greater at 15 °C than at 10 °C and 5 °C. 3 A greater proportion of plants visited by aphids was infected with BYDV when plants were stressed than when not stressed. At 15 °C a greater proportion of these plants was infected than at lower temperatures. There was no difference between treatments in the numbers of aphids present at the end of the experiment. 4 It is concluded that drought stress and temperature are of considerable importance in virus spread. [source]

    Magnitude of nighttime transpiration does not affect plant growth or nutrition in well-watered Arabidopsis

    PHYSIOLOGIA PLANTARUM, Issue 3 2009
    Mairgareth A. Christman
    Significant water loss occurs throughout the night via partially open stomata in many C3 and C4 plant species. Although apparently wasteful in terms of water use, nighttime transpiration (Enight) is hypothesized to benefit plants by enhancing nutrient supply. We tested the hypothesis that plants with greater Enight would have improved plant nutrient status and greater fitness, estimated as pre-bolting biomass, for Arabidopsis thaliana. Two very different levels of Enight were generated in plants by exposing them to high vs low nighttime leaf-to-air vapor pressure deficits (VPDleaf) in controlled environment chambers. An assessment of responses of nighttime leaf conductance (gnight) to VPDleaf indicated that Enight differed by at least 80% between the treatments. This large difference in Enight, imposed over the entire vegetative growth phase of Arabidopsis, had no effect on leaf nutrient content (N, Ca, K) or pre-bolting rosette biomass. The lack of response to differences in Enight held true for both a high and a low nitrogen (N) treatment, even though the low N treatment decreased leaf N and biomass by 40,60%. The N treatment had no effect on gnight. Thus, higher Enight did not provide a nutrient or growth benefit to Arabidopsis, even when the plants were N-limited. [source]