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62. Combined effects of cadmium and ozone on photosynthesis of Lycopersicon esculentum

Creator:
Degl’Innocenti, E., Castagna, A., Ranieri, A., and Guidi, L.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, ozon, rajčata, kadmium, photosynthesis, ozone, tomatoes, cadmium, chlorophyll a fluorescence, de-epoxidation index, electron transport rate, gas exchange, xanthophyll cycle, Lycopersicon esculentum, 2, and 581
Language:
Multiple languages
Description:
Tomato (Lycopersicon esculentum Mill. cv. Pearson) plants were grown in growth chambers for 25 days with cadmium (Cd) and then exposed briefly to ozone (O3). Gas exchange, chlorophyll a fluorescence, and pigment composition were analysed in leaves at the end of the treatment to assess the effects of a single pollutant and their combination on photosynthesis. The CO2 assimilation rate was dramatically reduced in plants subjected to the combined treatment, while the single effect of Cd appeared less severe than that of O3. The decline of CO2 photoassimilation found in all O3-exposed plants was attributed to both stomatal and nonstomatal limitations. Tomato plants seemed to detoxify Cd to a great extent, but this resulted in growth suppression. In response to O3 exposure, the plants protected their photosystems by heat dissipation of excess energy via the xanthophyll cycle. Cd combined with O3 affected adversely this cycle resulting in an increase in photosynthetic performance under the same experimental light conditions., E. Degl’Innocenti, A. Castagna, A. Ranieri, L. Guidi., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

63. Combined effects of elevated CO2 concentration and drought stress on photosynthetic performance and leaf structure of cucumber (Cucumis sativus L.) seedlings

Creator:
Liu, B. B., Li, M., Li, Q. M., Cui, Q. Q., Zhang, W. D., Ai, X. Z., and Bi, H. G.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
abiotické faktory, chloroplasty, elektronová mikroskopie, abiotic factors, chloroplasts, electron microscopy, mezofyl, akumulace škrobu, stomata, mesophyll, starch accumulation, 2, and 581
Language:
Multiple languages
Description:
Drought stress is one of the main environmental factors limiting plant growth and productivity of many crops. Elevated carbon dioxide concentration (eCO2) can ameliorate, mitigate, or compensate for the negative impact of drought on plant growth and enable plants to remain turgid and functional for a longer period. In order to investigate the combined effects of eCO2 and drought stress on photosynthetic performance and leaf structures, we analyzed photosynthetic characteristics and structure and ultrastructure of cucumber leaves. The decline in net photosynthetic rate under moderate drought stress occurred due to stomatal limitation alone, while under severe drought stress, it was the result of stomatal and nonstomatal limitations. Conversely, eCO2 improved photosynthetic performance under moderate drought stress, increased the lengths of the palisade cells and the number of chloroplasts per palisade cell under severe drought stress, and significantly increased the grana thickness under moderate drought stress. Additionally, eCO2 significantly decreased stomatal density, stomatal widths and stomatal aperture on the abaxial surface of leaves under moderate drought stress. In conclusion, eCO2 can alleviate the negative effects of drought stress by improving the drought resistance of cucumber seedlings through stomatal modifications and leaf structure., B. B. Liu, M. Li, Q. M. Li, Q. Q. Cui, W. D. Zhang, X. Z. Ai, H. G. Bi., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

64. Combined stresses of light and chilling on photosynthesis of Fraxinus mandschurica seedlings in northeastern China

Creator:
Li, X. F., Jin, L., Zhu, C. Y., Wen, Y. J., and Wang, Y.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, mírné pásmo, photosynthesis, temperate zone, chlorophyll fluorescence, early-spring chilling, net photosynthetic rate, 2, and 581
Language:
Multiple languages
Description:
The chilling and light stresses were experimentally created to explore photosynthesis of Fraxinus mandshurica seedlings in northeast China. Net photosynthetic rate, stomatal conductance, and transpiration rate decreased significantly with the decline of temperature and light. Significant interaction effects of light and chilling were observed on gas exchange of photosynthesis. The minimal fluorescence yield of the dark-adapted state (F0) increased with increasing light and decreasing temperature. Both high and low light stresses induced the decreases of the maximal quantum yield of PSII photochemistry (Fv/Fm), photochemical quenching coefficient (qP), nonphotochemical quenching (NPQ), and electron transport rate. Decline of Fv/Fm and increased F0 were observed under decreasing temperatures. Decreased NPQ and qP at frost temperature suggest that F. mandschurica failed to dissipate excess light energy. No interactive effects of chilling and light on chlorophyll fluorescence parameters suggests that F. mandschurica seedlings might be adapted to combined stresses of light and chilling., X. F. Li, L. Jin, C. Y. Zhu, Y. J. Wen, Y. Wang., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

65. Community-wide consequences of variation in photoprotective physiology among prairie plants

Creator:
Kothari, S., Cavender-Bares, J., Bitan, K., Verhoeven, A. S., Wang, R., Montgomery, R. A., and Gamon, J. A.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fenologie, phenology, drought, light-use efficiency, photoinhibition, trait covariance, water-use efficiency, 2, and 581
Language:
Multiple languages
Description:
Photoprotective pigments, like those involved in the xanthophyll cycle, help plants avoid oxidative damage caused by excess radiation. This study aims to characterize a spectrum of strategies used to cope with light stress by a diverse group of prairie plants at Cedar Creek Ecosystem Science Reserve (East Bethel, MN). We find that concentrations of photosynthetic and photoprotective pigments are highly correlated with one another and with other physiological traits across species and over time, and tend to be phylogenetically conserved. During a period of water limitation, plots dominated by species with constitutively low pigment concentrations showed a greater decline in mean reflectance and photochemical reflectance index, a reflectance-based indicator of photoprotective physiology, possibly due to alterations in canopy structure. Our findings suggest two contrasting strategies for withstanding light stress: (1) Using photoprotective pigments to dissipate excess energy, and (2) altering canopy structure to minimize absorbance of excess radiation., S. Kothari, J. Cavender-Bares, K. Bitan, A. S. Verhoeven, R. Wang, R. A. Montgomery, J. A. Gamon., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

66. Comparative analysis of drought stress effects on photosynthesis of Eurasian and North African genotypes of wild barley

Creator:
Jedmowski, C., Brüggemann, W., and Bayramov, S.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, ječmen, photosynthesis, barley, Hordeum, Calvin cycle, chlorophyll fluorescence, JIP-test, performance index, photosynthetic CO2 assimilation, drought stress, Hordeum spontaneum, 2, and 581
Language:
Multiple languages
Description:
The impact of drought stress (DS) on eight Eurasian and North African genotypes of wild barley (Hordeum spontaneum) was evaluated by analysis of chlorophyll (Chl) a fluorescence fast induction curves using the JIP-test. Three-week-old, pot-grown plants were exposed to a DS treatment by withholding water for nine days. The genotype-specific impairment of the functionality of the photosynthetic electron transport chain was quantified using the relative decline of the performance indices (PIabs and PItot), two key parameters of the JIP-test. The genotypes showing the highest (HOR10164) and lowest (HOR10710) relative PIs under DS were subjected to additional experiments, including measurements of leaf gas exchange, water status, pigment content, key enzyme activity, and protein abundance. The genotypes showed a specific profile of DS-mediated inhibition of photosynthesis, associated with higher relative leaf water contents in HOR10164 at the end of the treatment. Whereas decreased photosynthetic rate in HOR10164 was mainly caused by stomatal closure, nonstomatal limitations (decreased Rubisco content and activity) were detected in HOR10710. Additional genotype specific features were the upregulation of the NADP-malate dehydrogenase in HOR10164 and a decreased fraction of QA-reducing reaction centers in HOR10710., C. Jedmowski, S. Bayramov, W. Brüggemann., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

67. Comparative analysis of ultrastructure, antioxidant enzyme activities, and photosynthetic performance in rice mutant 812HS prone to photooxidation

Creator:
Ma, J., Lv, C. F., Zhang, B. B., Wang, F., Shen, W. J., Chen, G. X., Gao, Z. P., and Lv, C. G.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
obecná botanika, bílkoviny, general botany, proteins, malondialdehyde, photophosphorylation, reactive oxygen species, 2, and 581
Language:
Multiple languages
Description:
Under optimal conditions, most of the light energy is used to drive electron transport. However, when the light energy exceeds the capacity of photosynthesis, the overall photosynthetic efficiency drops down. The present study investigated the effects of high light on rice photooxidation-prone mutant 812HS, characterized by a mutation of leaf photooxidation 1 gene, and its wild type 812S under field conditions. Our results showed no significant difference between 812HS and 812S before exposure to high sunlight. However, during exposure to high light, shoot tips of 812HS turned yellow and their chlorophyll (Chl) content decreased. Transmission electron microscopy showed that photooxidation resulted in significant damage of chloroplast ultrastructure. It was confirmed also by inhibited photophosphorylation and reduced ATP content. The decreased coupling factor of ATP, Ca2+-ATPase and Mg2+-ATPase activities also verified these results. Further, significantly enhanced activities of antioxidative enzymes were observed during photooxidation. Malondialdehyde, hydrogen peroxide, and the superoxide generation rates also increased. Chl a fluorescence analysis found that the performance index and maximum quantum yield of PSII declined on August 4, 20 days after high-light treatment. Net photosynthetic rate also decreased and substomatal CO2 concentration increased in 812HS at the same time. In conclusion, our findings indicated that excessive energy triggered the production of toxic reactive oxygen species and promoted lipid peroxidation in 812HS plants, causing severe damage to cell membranes, degradation of photosynthetic pigments and proteins, and ultimately inhibition of photosynthesis., J. Ma, C. F. Lv, B. B. Zhang, F. Wang, W. J. Shen, G. X. Chen, Z. P. Gao, C. G. Lv., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

68. Comparative chloroplast proteome analysis of exogenously supplied trehalose to wheat seedlings under heat stress

Creator:
Luo, Y., Liu, H. Y., Fan, Y. Z., Wang, W., and Zhao, Y. Y.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
chloroplasty, chloroplasts, chlorophyll fluorescence, photosynthesis-related proteome, PSI activity, 2, and 581
Language:
Multiple languages
Description:
The aim of our study was to investigate the underlying molecular mechanisms of exogenously supplied trehalose affecting wheat photosynthesis under heat stress. The amount of ATP synthase (ATPase), oxygen-evolving enhancer protein (OEE), PsbP, Rubisco, chloroplast fructose-bisphosphate aldolase (FBPA), and ferredoxin-NADP(H) oxidoreductase (FNR) were downregulated, while PSI reaction center subunits were upregulated under heat stress. However, in the trehalose-pretreated groups, the amount of FNR, cytochrome b6f complex, PSI reaction center subunits, ATPase, FBPA, and Rubisco were upregulated under normal growth conditions and heat stress. Besides, during the recovery period, the upregulation in CAB, PsbP, OEE2, and ATPase suggested that trehalose pretreatment might help to the recovery of PSII and PSI. These results indicate that trehalose pretreatment effectively regulates the levels of the photosynthesis-related proteins and relieves the damage of heat stress to wheat chloroplast., Y. Luo, H. Y. Liu, Y. Z. Fan, W. Wang, Y. Y. Zhao., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

69. Comparative photosynthetic attributes of emmer and modern wheats in response to water and nitrogen supply

Creator:
Vaghar, M. and Ehsanzadeh, P.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
hnojiva, chlorofyl, závlahy, fertilizers, chlorophyll, irrigation, hulled wheat, water-use efficiency, 2, and 581
Language:
Multiple languages
Description:
A field study was conducted with the aim to elucidate photosynthetic responses of five emmer hulled wheat (Triticum turgidum ssp. dicoccum) accessions to 30 (N-limited) and 100 kg(N) ha-1 (N-sufficient) conditions at control and drought stress (irrigation after 30-40% and 60-70% depletion of available soil water, respectively). Chlorophyll (Chl) a and Chl b concentrations of the emmer wheats remained unchanged but net photosynthetic rate and dry mass increased and decreased, respectively, when received a sufficient amount of N. Smaller drought-induced decreases in Chl concentration, membrane stability index, and dry mass were concomitant to a greater decrease in intercellular CO2 concentration of emmer compared to the durum (Triticum turgidum) and bread wheats (Triticum aestivum). The lack of negative effect of insufficient N on Chl concentration and dry mass of emmer wheat suggests that this type of wheat possesses an obvious potential for organic farming., M. Vaghar, P. Ehsanzadeh., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

70. Comparative studies of compatible and incompatible pepper-Tobamovirus interactions and the evaluation of effects of 24-epibrassinolide

Creator:
Janeczko, A., Dziurka, M., Gullner, G., Kocurek, M., Rys, M., Saja, D., Skoczowski, A., Tóbiás, I., Kornas, A., and Barna, B.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
brassinosteroidy, brassinosteroids, CO2 asimilace, xantofylový cyklus, CO2 assimilation, systemic virus response, water band index, xanthophyll cycle, 2, and 581
Language:
Multiple languages
Description:
The aim of study was to gain a deeper knowledge about local and systemic changes in photosynthetic processes and sugar production of pepper infected by Obuda pepper virus (ObPV) and Pepper mild mottle virus (PMMoV). PSII efficiency, reflectance, and gas exchange were measured 48 and/or 72 h after inoculation (hpi). Sugar accumulation was checked 72 hpi and 20 d after inoculation (as a systemic response). Inoculation of leaves with ObPV led to appearance of hypersensitive necrotic lesions (incompatible interaction), while PMMoV caused no visible symptoms (compatible interaction). ObPV (but not PMMoV) lowered Fv/Fm (from 0.827 to 0.148 at 72 hpi). Net photosynthesis decreased in ObPV-infected leaves. In ObPV-inoculated leaves, the accumulation of glucose, fructose, and glucose-6-phosphate was accompanied with lowered sucrose, maltoheptose, nystose, and trehalose contents. PMMoV inoculation increased the contents of glucose, maltose, and raffinose in the inoculated leaves, while glucose-6-phosphate accummulated in upper leaves., A. Janeczko, M. Dziurka, G. Gullner, M. Kocurek, M. Rys, D. Saja, A. Skoczowski, I. Tóbiás, A. Kornas, B. Barna., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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