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12. Flavonoid responses in wheat grown at elevated CO2: green versus senescent leaves
- Creator:
- Peñuelas, J., Estiarte, M., and Kimball, B. A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carbon based secondary compounds (CBSC), isoorientin, leaf age, litter, phenolics, tricin, and Triticum aestivum
- Language:
- Multiple languages
- Description:
- We compared flavonoids in green, mature, and senescing flag leaves of wheat grown under ambient (AC - 370 μmol mol-1) and elevated (EC - 550 μmol mol-1) concentrations of CO2 in a FACE (Free Air CO2 Enrichment) system. The concentrations of flag leaf flavonoids (e.g., isoorientin and tricin) decreased to one third in mature leaves, and the majoritary isoorientin almost disappeared in senescing leaves. Flavonoid concentrations increased in green well-developed flag leaves under EC (46 % isoorientin and 55 % tricin), whereas the differences disappeared in mature and senescing flag leaves. Predictions of changes in litter phenolic concentrations and their effects on decomposition rates under EC based on changes in green leaves need to be revised. and J. Peñuelas, M. Estiarte, B. A. Kimball.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
13. Formation of cross-linking between photosystem 2 proteins during irradiation of thylakoid membranes at high temperature
- Creator:
- Singh, Abhay K. and Singhal, G. S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- D1 protein, diphenylcarbazide, oxygen evolving complex, scavengers, Triticum aestivum, and wheat
- Language:
- Multiple languages
- Description:
- Irradiation of thylakoid membranes at 40 °C resulted in complete inhibition of photosystem (PS) 2 activity measured as 2,6-dichlorophenol indophenol (DCIP) photoreduction either in the absence or presence of 1,5-diphenylcarbazide (DPC). Concomitant with the inactivation of PS2 activity, several thylakoid proteins were lost and high molecular mass cross-linking products appeared that cross-reacted with antibodies against proteins of PS2 but not with antibodies against proteins of other three complexes PS1, ATP synthase, and cytochrome b6f. Irradiation of thylakoid membranes suspended in buffer of basic pH or high concentration of Tris at 25 °C resulted in the formation of cross-linking products similar to those in thylakoid membranes irradiated at 40 °C. Presence of radical scavengers and DPC during the high temperature treatment prevented the formation of cross-linking products. These results suggest the involvement of oxygen evolving co mplex (OEC) in the formation of cross-linking between PS2 proteins in thylakoid membrane irradiated at high temperature. and Abhay K. Singh, G. S. Singhal.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
14. Induction of porphyrin biosynthesis by 5-aminolevulinic acid, glutamic acid, and 1,10-phenanthroline and their possible photodynamic action in wheat and mustard plants
- Creator:
- Toneva, V., Gechev, T., and Minkov, I.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- protochlorophyllide, photoherbicide effect, photoporphyrin IX, Triticum aestivum, and Sinapis alba
- Language:
- Multiple languages
- Description:
- The photodynamic damage of the sensitive plants wheat and mustard, treated with chlorophyll (Chl) precursors 5-aminolevulinic acid (ALA) and glutamic acid (Glu) and with 1,10-phenanthroline (Phen), was caused by tetrapyrroles, which accumulated after 17 h in the dark period, followed by 12 h of irradiation with "white light". The effect of accumulated Chl in mustard plants was accompanied by changes in the amounts of the Chls and carotenoids and by dehydration of the tissues, partial chlorosis, and necrosis. The molecular nature of the specific photodynamic sensitivity of the mustard and wheat plants under the influence of Phen and Chl precursors was important: accumulation of tetrapyrroles was a necessary, but not only reason for photodynamic damage of the plants. The degree of leaf damage was related to the amount and chemical nature of accumulated tetrapyrroles and to the greening group to which the investigated plant belongs. and V. Toneva, T. Gechev, I. Minkov.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
15. Influence of water stress on leaf photosynthetic characteristics in wheat cultivars differing in their susceptibility to drought
- Creator:
- Subrahmanyam, D., Subash, N., Haris, A., and Sikka, A. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, net photosynthetic rate, stomatal conductance, transpiration rate, Triticum aestivum, and water potential
- Language:
- Multiple languages
- Description:
- A gradual reduction in leaf water potential (Ψleaf), net photosynthetic rate (PN), stomatal conductance, and transpiration rate was observed in two drought tolerant (C 306 and K 8027) and two susceptible (RW 893 and 899) genotypes subjected to water stress. The extent of reduction was lower in K 8027 and C 306 and higher in RW 893 and RW 899. Rewatering the plants after 5 d of stress restored PN and other gas exchange traits in all four cultivars. Water stress had no significant effect on variable to maximum fluorescence ratio (Fv/Fm) indicating that water stress had no effect on primary photochemistry of photosystem 2 (PS2). However, water stress reduced the efficiency of excitation energy transfer (F'v/F'm) and the quantum yield of electron transport (ΦPS2). The reduction was more pronounced in susceptible cultivars. Water stress had no significant effect on photochemical quenching, however, the non-photochemical quenching increased by water stress. and D. Subrahmanyam ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
16. Modelling net photosynthetic rate of winter wheat in elevated air CO2 concentrations
- Creator:
- Harnos, N., Tuba, Z., and Szente, K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- acclimation, carotenoids, chlorophyll, intercellular CO2 concentration, leaf area, net photosynthetic rate, ribulose-1,5-bisphosphate carboxylase/oxygenase capacity, temperature, and Triticum aestivum
- Language:
- Multiple languages
- Description:
- Winter wheat plants were grown in open top chambers either at 365 µmol mol-1 (AC) or at 700 µmol mol-1 (EC) air CO2 concentrations. The photosynthetic response of flag leaves at the beginning of flowering and on four vertical leaf levels at the beginning of grain filling were measured. Net photosynthetic rates (PN) were higher at both developmental phases in plants grown at EC coupled with larger leaf area and photosynthetic pigment contents. The widely accepted Farquhar net photosynthesis model was parameterised and tested using several observed data. After parameterisation the test results corresponded satisfactorily with observed values under several environmental conditions. and N. Harnos, Z. Tuba, K. Szente.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
17. Photosynthesis and growth of winter wheat in response to waterlogging at different growth stages
- Creator:
- Shao, G. C., Lan, J. J., Yu, S. E., Liu, N., Guo, R. Q., and She, D. L.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, grain yield, wheat growth stages, milky stage, plant growth, tillering, Triticum aestivum, 2, and 581
- Language:
- Multiple languages
- Description:
- A study on photosynthetic and yield effects of waterlogging of winter wheat at four stages of growth was conducted in specially designed experimental tanks during the 2007-2008 and 2008-2009 seasons. Compared with the control, waterlogging treatments at tillering and jointing-booting stages reduced photosynthetic rate (PN) and transpiration (E) significantly, it also decreased average leaf water-use efficiency (WUE, defined as the ratio of PN to E) by 3.3% and 3.4% in both years. All parameters returned quickly to the control level after soil was drained. Damage to the photosynthetic apparatus during waterlogging resulted in a lower Fv/Fm ratio, especially at the first two stages. A strong reduction in root length, root mass, root/shoot ratio, total dry mass, and leaf area index were observed. The responses from vegetative plants at tillering and jointing-booting stages were greater than in generative plants at onset of flowering and at milky stages. The number of panicles per hectare at tillering stage and the spikelet per panicle at the stages of jointing-booting and at onset of flowering were also significantly reduced by waterlogging, giving 8.2-11.3% decrease of the grain yield relative to the control in both years. No significant difference in yield components and a grain yield was observed between the control and treatments applied at milky stages. These responses, modulated by the environmental conditions prevailing during and after waterlogging, included negative effects on the growth, photosynthetic apparatus, and the grain yield in winter wheat, but the effect was strongly stage-dependent. and G. C. Shao ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
18. Photosynthetic and yield responses of an old and a modern winter wheat cultivars to short-term ozone exposure
- Creator:
- Xu, H., Chen, S.-B., Biswas, D.-K., Li, Y.-G., and Jiang, G.-M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- air pollution, gas exchange, post-anthesis, stomatal conductance, and Triticum aestivum
- Language:
- Multiple languages
- Description:
- In order to study the responses of winter wheat cultivars released in different years to short-term high O3 exposure, an old cultivar ('Nongda 311', released in 1960s) and a modern one ('Yannong 19', released in 1990s) were treated with an O3 exposure (145 ± 12 mm3 m-3, 4 h d-1 for 3 d) shortly after anthesis stage (> 50 % main stems blossomed). During the O3 exposure, light-saturated photosynthetic rate (PN) and stomatal conductance (gs) of both cultivars decreased considerably. Elevated O3 did not decrease dark-adapted maximum photochemical efficiency, but induced significant reduction in actual photochemical efficiency and thereby considerably increase in non-photochemical quenching. PN, gs of the modern cultivar 'Yannong 19' decreased more than the older one 'Nongda 311', indicating the former exhibited higher sensitivity to O3 than the latter. After O3 exposure, PN, gs and chlorophyll (Chl) content in flag leaf decreased more quickly than control, indicating induction of faster premature leaf senescence. As a result, the short-term O3 exposure caused substantial yield loss, with larger reduction in 'Yannong 19' (-19.2 %) than in 'Nongda 311' (-8.4 %). Our results indicated that high O3 exposure at grain filling stage would have greater negative impacts on the high yielding modern cultivar relative to the old one with lower yield. and H. Xu ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
19. Photosynthetic characteristics of chloroplasts of primary wheat leaves grown under different irradiance
- Creator:
- Behera, Rajendra K. and Choudhury, Nakul K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carotenoids, chlorophyll fluorescence, Hill activity, leaf ageing, membrane polarisation, senescence, Triticum aestivum, and wheat
- Language:
- Multiple languages
- Description:
- The rate of accumulation of total chlorophyll (Chl) and carotenoids (Car) of leaves grown under high irradiance, HI (30 and 45 W m-2) was faster than at moderate irradiance, MI (15 W m-2). However, the senescence phase started earlier in the samples and proceeded at a faster rate. Chl a/b and Chl (a+b)/Car values showed faster loss of Chl a (compared to Chl b) and Chl (a+b) (compared to Car) in HI leaves. Protein accumulation and loss were also similar to that of Chl (a+b) content. Increase in Chl fluorescence during the development phase may suggest a gradual change in thylakoid organisation, however, the temporal kinetics were different in HI and MI samples. Increase in fluorescence polarisation during senescence of HI leaves compared to the control (MI) suggests conversion of thylakoid membranes to gel phase. Chloroplasts prepared from HI seedlings showed higher rate of photochemical activities, however, the activity declined earlier and at faster rate compared to the control. and Rajendra K. Behera, Nakul K. Choudhury.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
20. Photosynthetic characteristics of non-leaf organs of winter wheat cultivars differing in ear type and their relationship with grain mass per ear
- Creator:
- Wang, Zhi-Min, Wei, Ai-Li, and Zheng, Dan-Man
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll, net synthetic rate, photosystem 2, ribulose-1,5-bisphosphate carboxylase/oxygenase, and Triticum aestivum
- Language:
- Multiple languages
- Description:
- Chlorophyll content, photosystem 2 functioning (Fv/Fm, Fv/F0), activity of ribulose-1,5-bisphosphate carboxylase/oxygenase, and net photosynthetic rates (PN) of flag leaf blade, sheath, peduncle, and ear organs were assessed in large-ear type (Pin 7) and small-ear type (ND93) wheat cultivars. Some differences were found in photosynthetic properties between different green plant parts, the values of all studied parameters in ear parts being higher in Pin7 than in ND93. Furthermore, ear surface areas and ear PN in 26 wheat genotypes measured at anthesis showed highly significant positive correlation with grain mass per ear. Hence a greater capability of ear photosynthesis may result in a greater grain yield in large-ear type cultivars. and Zhi-Min Wang, Ai-Li Wei, Dan-Man Zheng.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
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