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81.
Elevated CO2 decreases seed germination in Arabidopsis thaliana 总被引:2,自引:0,他引:2
CHRISTOPHE ANDALO BERNARD GODELLE † MADELEINE LEFRANC MARIANNE MOUSSEAU IRÉNE TILL-BOTTRAUD 《Global Change Biology》1996,2(2):129-135
The impact of elevated [CO2] on seed germination was studied in different genotypes of Arabidopsis thaliana from natural populations. Two generations of seeds were studied: the maternal generation was produced in the greenhouse (present-day conditions), the offspring generation was produced in two chambers where the CO2 concentration was either the present atmospheric concentration (about 350 ppm) or elevated (700 ppm). The seeds were tested for proportion of germinated seeds and mean germination time in both chambers to study the impact of elevated [CO2] during seed production and germination. Elevated [CO2] during maturation of seeds on the mother-plants decreased the proportion of germinated seeds, while elevated [CO2] during germination had no effect on the proportion of germinated seeds. However, when seeds were both produced and germinated under elevated [CO2] (situation expected by the end of next century), germination was slow and low. Moreover, the effect of the [CO2] treatment differs among genotypes of Arabidopsis: there is a strong treatment × genotype interaction. This means that there is ample genetic variance for a selective response modiying the effects of high levels of [CO2] in natural populations of Arabidopsis thaliana. The outcome at the community level will depend on what seeds are available, when they germinate and the resulting competition following germination. 相似文献
82.
Lamaze, T., Sentenac, H. and Grignon, C. 1987. Orthophosphaterelations of root: NO3effects on orthophosphate influx,accumulation and secretion into the xylem.J. exp. Bot.38: 923934. Orthophosphate (Pi) accumulation by barley (Hordeum vulgareL.) roots was specifically inhibited by NO3 as comparedto Cl and SO42 , and Pi secretion into the xylemwas stimulated. The inhibition of Pi accumulation by NO3was also observed in roots of intact photosynthesizing horsebean(Vicia faba L.), rice (Oryza sativa L.) and soybean (Glycinemax L.) plants. NO3 effects on Pi transport by rootswere more thoroughly investigated with corn (Zea mays L.). Theywere due to intracellular NO3. Pi secretion was stillstimulated by NO3 after Pi withdrawal from the absorptionsolution. 32Pi influx decreased during Pi accumulation, supportingthe hypothesis that this ion allosterically regulated its owntransport system by feedback control. This control was modulatedby other anions: the decrease was more pronounced in the presenceof nitrate. Chronologically, the depressive effect of NO3on 32Pi influx appeared after the inhibition of Pi accumulation.Furthermore, under conditions where Pi accumulation was notaffected by NO3, 32Pi influx and Pi secretion into thexylem became insensitive to the presence of nitrate. Our hypothesisis that the stimulative effect of NO3 on Pi secretionand the depressive one on 32Pi influx are the repercussionsof an increase in the Pi cytosolic concentration due to an NO3-induced decrease in Pi uptake by the vacuoles. Key words: Root, orthophosphate fluxes, orthophosphate accumulation, nitrate, ionic interaction 相似文献
83.
The 36 species of the tribe Pronophilini known from the Cordillera de Merida, the main Andean mountain range in Venezuela, are listed, together with three others probably erroneously described or labelled as from the range. The general ecological characteristics of the tribe are described, using the Merida species as examples. These include its restriction to high altitudes, endemism in mountain 'islands', species partitioning up the altitude gradient, mimicry within the tribe, and seasonality. The evolutionary relationships of the 16 endemic species are analyzed. Two new genera, six new species, two new subspecies and one new form are described. Three new synonymies are established, three new combinations made, new status is given to two taxa and the status of one taxon is revised. 相似文献
84.
85.
The effects of long-term and transient exposure to elevatedCO2 concentrations on photosynthetic gas exchange and ethylenerelease by tomato leaves were investigated. The net CO2 assimilationrate was enhanced when leaf tissue grown at ambient (35 Pa CO2)levels was assayed at 100 Pa CO2. Leaf tissue grown at high(130 Pa) CO2 exhibited a lower net CO2 assimilation rate athigh CO2 levels than leaf tissue grown at ambient (35 Pa) CO2.This decrease in CO2 exchange rate in response to growth athigh CO2 is typical of C3 species. Rates of endogenous and 1-aminocyclopropane-l-carboxylicacid (ACC)-stimulated ethylene release from leaf tissue wereenhanced by exposure to elevated CO2 levels whether the leaftissue had been grown at ambient or enriched CO2 levels. Thedata demonstrate that CO2 enhanced C2H4 release from leaf tissuein response to both short-term perturbations in CO2 concentrationand long-term growth and development under high CO2. Prolongedgrowth at elevated CO2 concentrations induced a higher endogenousrate of C2H4 release relative to that of leaf tissue grown atlower CO2 levels. Leaf tissue from all leaf positions of plantsgrown at high CO2 consistently evolved more C2H4 than correspondingtissue from ambient-grown plants when assayed under standardizedconditions. Endogenous (ACC) tissue contents and rates of ACC-stimulatedethylene release were also higher at all leaf positions in CO2-enrichedtissue. Thus the higher rates appeared to be due to both higherendogenous precursor (ACC) levels in the tissue and greaterACC to C2H4 conversion capacity. Growth at elevated CO2 levelsresulted in a persistent increase in the rate of endogenousC2H4 release in leaf tissue. The capacity for increased ethylenerelease in response to CO2 did not decline after prolonged growthat high CO2. Key words: CO2enrichment, ethylene, leaves, tomato 相似文献
86.
87.
Bulbs were obtained on onion plants cultured in vitro. No bulbinghappened under long days with fluorescent light and 3040g l1 sucrose. Bulb formation was mainly dependent eitheron sucrose concentration in the culture medium, or on lightspectral composition. Raising the sucrose concentration from40 to 120 g l1 increased plant basal swelling and stoppedfurther vegetative development. These plants were not dormant.When fluorescent light was enriched in incandescence duringa long day period, bulbs were obtained in two months and underwenta consecutive dormancy. Bulb, dormancy, light spectral quality, photoperiod, R: FR ratio, sugar, tissue culture 相似文献
88.
89.
Multivariate analysis, specifically principal components analysis,shows that in flowering plants structures occur that arc intermediatebetween the typical representatives of a root, a caulome (stemand stem homologues), a phyllome (leaf and leaf homologues),a shoot and a trichome. Since these intermediates span the wholerange between the typical forms, a morphological continuum isdocumented. Implications and consequences of these findingsare discussed (e.g. homology, homeosis). The telome theory andHagemann's theory of the evolution of plant form are interpretedas referring to changes in the patterning of the morphologicalcontinuum. Plant morphology, principal components analysis, morphological continoum, angiosperms, flower, shoot, stem, leaf, enation, trichome, root, telome, thallus, morphological categories, homology, partial homology, homeosis 相似文献
90.