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41.
Epidermal strips from either well-watered or water-stressedplants of Commelina communis L. were subjected to a range ofABA concentrations (106103 mol m3)in the presence (330 parts 106 in air) or virtual absence(3 parts 106 in air) of CO2. The stomatal response toCO2 was greater in epidermis from water-stressed plants, althoughthere was a distinct CO2 response in epidermis from well-wateredplants. Additions of ABA via the incubation medium had littleeffect on the relative CO2 response. Stomata responded to ABAboth in the presence and virtual absence of CO2, but the relativeresponse to ABA was greatest in the high CO2 treatment. Whenwell-watered plants were sprayed with a 101 mol m3ABA solution 1 d prior to use, the stomatal response of detachedepidermis to both CO2 and ABA was very similar to that of epidermisdetached from water-stressed leaves. It is hypothesized thata prolonged exposure to ABA is necessary before there is anymodification of the CO2 response of stomata. 相似文献
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Cells from the sub-epidermal layer of Pilea cadierei preparedfor electron microscopy using standard fixation and embeddingprocedures appear extremely osmiophilic, with the organellesstanding out in negative relief. However, when tissues werefixed in glutaraldehyde supplemented with either procaine orcaffeine (substances known to complex with phenols) the osmiophilicmaterial was generally limited to the vacuole. After procaineor caffeine fixation the surrounding cytoplasm appeared as inadjacent, nonphenolic cells. Some small aggregates of phenolicmaterial appear in the cisternae of the endoplasmic reticular,indicating these organelles may be involved in either the synthesisor transport of phenolics in Pilea. Since one of the major functionsof phenolics is in light-screening, air blisters may serve toscreen out damaging radiation from the underlying tissue. Thepresence of typical shade-type plastids in Pilea air blistersis a further indication of this light-screening role. Pilea cadierei, aluminium plant, air blister, cytochemistry, ultrastructure, light screening, phenolics 相似文献
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Effects of carbon dioxide concentration on the interactive effects of temperature and water vapour on stomatal conductance in soybean 总被引:2,自引:1,他引:1
Soybeans were grown at three CO2 concentrations in outdoor growth chambers and at two concentrations in controlled-environment growth chambers to investigate the interactive effects of CO2, temperature and leaf-to-air vapour pressure difference (LAVPD) on stomatal conductance. The decline in stomatal conductance with CO2 was a function of both leaf temperature and LAVPD. In the field measurements, stomatal conductance was more sensitive to LAVPD at low CO2 at 30 °C but not at 35 °C. There was also a direct increase in conductance with temperature, which was greater at the two elevated carbon dioxide concentrations. Environmental growth chamber results showed that the relative stomatal sensitivity to LAVPD decreased with both leaf temperature and CO2. Measurements in the environmental growth chamber were also performed at the opposing CO2, and these experiments indicate that the stomatal sensitivity to LAVPD was determined more by growth CO2 than by measurement CO2. Two models that describe stomatal responses to LAVPD were compared with the outdoor data to evaluate whether these models described adequately the interactive effects of CO2, LAVPD and temperature. 相似文献
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The excision of cotyledons from two cultivars of peas soon aftergermination resulted in a lowering of the node of first floweringas well as a delay in both flower initiation and flowering,especially in the late cultivar Greenfeast. This is contraryto the usual view that, when cotyledon excision reduces nodeof first flowering, flower initiation and flowering are hastened,and it seems irreconcilable with the colysanthin theory of Barber(1959). An alternative explanation is proposed. 相似文献
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Sphagnum mosses are major components of peat bogs but populations of many species are under threat due to habitat fragmentation resulting from the cutting of peat for fuel. We have used an intersimple sequence repeat (ISSR)‐based cloning method to develop nine polymorphic nuclear microsatellites for the peat moss species Sphagnum capillifolium. Between three and seven alleles per locus were detected in a sample of 48 haploid gametophytes and levels of gene diversity ranged from 0.5391 to 0.7960. These represent the first microsatellite markers developed for this important genus and most also exhibited cross‐species amplification across a range of common Sphagnum species. 相似文献
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