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2902. Irradiance acclimation, capture ability, and efficiency in invasive and non-invasive alien plant species
- Creator:
- Feng, Y.-L., Wang, J.-F., and Sang, W.-G.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carbon costs, chlorophyll fluorescence, irradiance, morphology, nitrogen allocation, photosynthesis, and photosynthetic nitrogen utilization efficiency
- Language:
- Multiple languages
- Description:
- We tested the hypothesis that invasive (IN) species could capture resources more rapidly and efficiently than noninvasive (NIN) species. Two IN alien species, Ageratina adenophora and Chromolaena odorata, and one NIN alien species, Gynura sp. were compared at five irradiances. Photon-saturated photosynthetic rate (Pmax), leaf mass (LMA) and nitrogen content (NA) per unit area, and photosynthetic nitrogen utilization efficiency (PNUE) increased significantly with irradiance. LMA, NA, and PNUE all contributed to the increased Pmax, indicating that both morphological and physiological acclimation were important for the three alien species. Under stronger irradiance, PNUE was improved through changes in N allocation. With the increase of irradiance, the amount of N converted into carboxylation and bioenergetics increased, whereas that allocated to light-harvesting components decreased. The three alien species could adequately acclimate to high irradiance by increasing the ability to utilize and dissipate photon energy and decreasing the efficiency of photon capture. The two IN species survived at 4.5 % irradiance while the NIN species Gynura died, representing their different invasiveness. Ageratina generally exhibited higher respiration rate (RD) and NA. However, distinctly higher Pmax, PNUE, Pmax/RD, or Pmax/LMA were not detected in the two invasive species, nor was lower LMA. Hence the abilities to capture and utilize resources were not always associated with invasiveness of the alien species. and Y. L. Feng, J. F. Wang, W. G. Sang.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2903. Irradiance dependence and action spectra of photosynthesis. I. Theoretical consideration
- Creator:
- Maslenkova, L.T., Pencheva, B.R., and Zeinalov, Yu.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- Analysis of the photosynthetic irradiance curves (IC), and action and quantum efficiency spectra on the basis of the model of Kok ei al. (1970) showed that under a low irradiance all ÍC, irrespective of sample absorbances, had non-linear (exponential) parts. Under a high irradiance, the IC (especially those of higher situated sublayers) showed "saturation", which was expressed as a decrease in the dechne of the curves. The IC non-linearity was reflected in the shape of the photosynthetic action spectra (AS). Under a low irradiance, the AS showed a decrease (drop) in the spectral regions with low absorbances, i.e. between 500 and 650 nm, as well as above 690 nm (Emerson s "red drop effect"). On the contrary, under higher irradiances an increase in quantum esfficiency (QE) in the same regions was well-expressed. When IC were non-linear, exact estimation of the photosynthetic AS and QE was much complicated and respective results should be accepted with a fair approach to accuracy.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2904. Irradiance effects on growth and bacteriochlorophyll content of phototrophic heliobacteria, purple and green photosynthetic bacteria
- Creator:
- Kimble-Long, L. K. and Madigan, M. T.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- anoxygenic phototrops, Chlorobium, generation time, Heliobacillus, Heliobacterium, photosynthetic pigments, and Rhodobacter
- Language:
- Multiple languages
- Description:
- Two species of heliobacteria along with a purple and green bacterium were tested for their ability to grow phototrophically at irradiances ranging from 0.125 to 50 W m-2. The heliobacteria were incapable of growth below 0.5 W m-2, while both the purple and green bacterium grew at significantly lower irradiances. Specific bacteriochlorophyll contents were higher for the purple and green bacteria than for the heliobacteria at all irradiances tested. Thus in distinct contrast to purple and green bacteria, heliobacteria are "high-irradiance" phototrophs, and this characteristic may influence their distribution in nature. and L. K. Kimble-Long, M. T. Madigan.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2905. Irradiance influences contents of photosynthetic pigments and proteins in tropical grasses and legumes
- Creator:
- Baig, M. J., Anand, A., Mandal, P. K., and Bhatt, R. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carotenoids, Cenchrus, chlorophyll, Dichantium, Macroptilium, Panicum, polyacrylamide gel electrophoresis, and Stylosanthes
- Language:
- Multiple languages
- Description:
- Three tropical range grasses (Cenchrus ciliaris, Dichanthium annulatum, and Panicum antidotale) and two range legumes [Macroptilium atropurpureum (siratro) and Stylosanthes hamata (stylo)] were grown under four irradiances, i.e. 100 (I100, control), 75 (I75), 50 (I50), and 25 (I25) % of full sunlight. Accumulation of chlorophyll (Chl) b increased but that of Chl a decreased under low irradiances. The greater accumulation of Chl (a+b) in grasses (particularly in D. annulatum and P. antidotale) under shade predicted their shade adaptability. Among legumes Stylosanthes was more adaptive to the shade than Macroptilium due to its higher accumulation of Chl (a+b). Significant difference in the accumulation of carotenoids under I25 over I100 was observed in all the species, which shows the increase in quality of the fodder under limited irradiance. There was a significant decrease in soluble protein content in C. ciliaris under I75, however, no significant difference in protein content was observed under I50 and I25, which was also reflected in the SDS pattern with the reduction in content of polypeptides at I75 and following increase at I50 and I25. This was possibly due to reduction of light-induced protein at I75 and then expression of the stress-induced protein at further reduction of irradiance. Peroxidase activity in C. ciliaris increased with the decrease in irradiance and its isozyme pattern showed differences among all treatments, which indicated the role of different peroxidase isoforms at different irradiances. and M. J. Baig ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2906. Irradiance influences tea leaf (Camellia sinensis L.) photosynthesis and transpiration
- Creator:
- Barman, T. S., Baruah, U., and Saikia, J. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- leaf temperature and photosynthetic photon flux density
- Language:
- Multiple languages
- Description:
- Rates of net photosynthesis (PN) and transpiration (E), and leaf temperature (TL) of maintenance leaves of tea under plucking were affected by photosynthetic photon flux densities (PPFD) of 200-2 200 µmol m-2 s-1. PN gradually increased with the increase of PPFD from 200 to 1 200 µmol m-2 s-1 and thereafter sharply declined. Maximum PN was 13.95 µmol m-2 s-1 at 1 200 µmol m-2 s-1 PPFD. There was no significant variation of PN among PPFD at 1 400-1 800 µmol m-2 s-1. Significant drop of PN occurred at 2 000 µmol m-2 s-1. PPFD at 2 200 µmol m-2 s-1 reduced photosynthesis to 6.92 µmol m-2 s-1. PPFD had a strong correlation with TL and E. Both TL and E linearly increased from 200 to 2 200 µmol m-2 s-1 PPFD. TL and E were highly correlated. The optimum TL for maximum PN was 26.0 °C after which PN declined significantly. E had a positive correlation with PN. and T. S. Barman, U. Baruah, J. K. Saikia.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2907. Irradiance prior to and during desiccation improves the tolerance to excess irradiance in the desiccated state of the old forest lichen Lobaria pulmonaria
- Creator:
- Štepigová, J., Gauslaa, Y., Cempírková-Vráblíková, H., and Solhaug, K. A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, photosynthetic quenching, photoinhibition, and xanthophyll cycle
- Language:
- Multiple languages
- Description:
- Hydrated thalli of the lichen Lobaria pulmonaria were either preconditioned to dim irradiance (DI, 5 µmol m-2 s-1) or medium irradiance (MI, 200 µmol m-2 s-1) for 6 h. After this 6 h period, the thalli were allowed to desiccate under the two respective irradiances. Thereafter, these dry lichens were exposed to high irradiance (HI, 1 000 µmol m-2 s-1) for 60 h. After this HI treatment, the maximal photochemical quantum yield (FV/FM) and the de-epoxidation state of xanthophyll cycle pigments (DEPS) were highest in thalli preconditioned to MI. Hence irradiance in the last hydrated period before sampling is significant for the physiological state of lichens. A standardized irradiance pre-treatment before start of experiments is recommended. and J. Štepigová ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2908. Irradiance stress responses of gas exchange and antioxidant enzyme contents in pariparoba [Pothomorphe umbellata (L.) Miq.] plants
- Creator:
- Marchese, J. A., Mattana, R. S., Ming, L. C., Broetto, F., Vendramini, P. F., and Moraes, R. M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- catalase, chlorophyll, oxidative stress, photosynthesis, shade plants, stomatal conductance, superoxide dismutase, and transpiration rate
- Language:
- Multiple languages
- Description:
- We evaluated the growth and development of the medicinal species Pothomorphe umbellata (L.) Miq. under different shade levels (full sun and 30, 50, and 70 % shade, marked as I100, I70, I50, and I30, respectively) and their effects on gas exchange and activities of antioxidant enzymes. Photosynthetically active radiation varied from 1 254 µmol m-2 s-1 at I100 to 285 µmol m-2 s-1 at I30. Stomatal conductance, net photosynthetic rate, and relative chlorophyll (Chl) content were maximal in I70 plants. Plants grown under I100 produced leaves with lower Chl content and signs of chlorosis and necrosis. These symptoms indicated Chl degradation induced by the generation of reactive oxygen species. Stress related antioxidant enzyme activities (Mn-SOD, Fe-SOD, and Cu/Zn-SOD) were highest in I100 plants, whereas catalase activity was the lowest. Hence P. umbellata is a shade species (sciophyte), a feature that should be considered in reforestation programs or in field plantings for production of medicinal constituents. and J. A. Marchese ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2909. Irradiation-induced in vivo re-localization of NADPH-protochlorophyllide oxidoreductase from prolamellar body to stroma of barley etioplast
- Creator:
- Kovacevic, D., Dewez, D., and Popovic, D.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll(ide), chloroplast development, envelope, fluorescence spectra, Hordeum vulgare, and prothylakoid
- Language:
- Multiple languages
- Description:
- Distribution of NADPH-protochlorophyllide oxidoreductase (POR) in etioplast of etiolated barley leaf was studied by using Western blot analyses of etioplast fractions isolated on a sucrose gradient. When the leaf was exposed to light, POR content decreased in the etioplast inner membrane and prolamellar body sub-membrane fraction while it was simultaneously increased in the stroma. By using 77 K fluorescence spectroscopy analyzes, we found for irradiated etiolated leaf that the POR protein in the stroma was co-localized with chlorophyllide (Chlide) emitting at 678 nm. Relocalization of the POR-Chlide complex induced by irradiation suggests that POR participates in the pigment transport processes during early stages of the thylakoid membrane development. and D. Kovacevic, D. Dewez, R. Popovic.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2910. Irradiation-regulated differential accumulation of chloroplast-encoded transcripts in mature leaves of Populus deltoides
- Creator:
- Srivastava, S., Trivedi, P. K., and Nath, P.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- dark adaptation, diurnal cycle, midday depression, Northern analysis, and ribulose-1,5-bisphosphate carboxylase/oxygenase
- Language:
- Multiple languages
- Description:
- Steady state transcript levels of psbA, rbcL, atpB, and psbN genes accumulated differentially in mature leaves of a field-grown tree Populus deltoides during natural diurnal cycle and in dark adaptation followed by irradiation. The rbcL transcript accumulated independent of irradiation under diurnal conditions, which demonstrated a correlation with the phenomenon of midday depression in photosynthesis. The psbA and atpB transcripts accumulated more in dark whereas psbN accumulated more in light. Diurnal rhythm of gene expression in mature chloroplasts was independent of development related changes. and S. Srivastava, P. K. Trivedi, P. Nath.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public