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2712. Relation between the heat-induced increase of F0 fluorescence and a shift in the electronic equilibrium at the acceptor side of photosystem 2
- Creator:
- Ducruet, J. M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- QA and QB sites, temperature, thermoluminescence, and Zea mays
- Language:
- Multiple languages
- Description:
- F0 fluorescence and thermoluminescence (TL) were recorded simultaneously on various dark-adapted leaf samples. Above 40 °C, a sharp peak of TL coincided with the onset of the heat-induced F0 rise. It results from a back-transfer of an electron from the secondary QB- to the primary acceptor QA of photosystem 2, followed by a luminescence-emitting recombination with Tyr-D1. This demonstrates that the critical temperature at which the F0 starts rising also corresponds to a shift towards the left of the QA↔QB- equilibrium.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2713. Relationship between acorn size and seedling morphological and physiological traits of Quercus ilex L. from different climates
- Creator:
- Bonito, A., Varone, L., and Gratani, L.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, acorn size, gas exchange, predawn leaf water potential, relative growth rate in height, relative water content at predawn, and total leaf area
- Language:
- Multiple languages
- Description:
- Effects of Quercus ilex acorn size on seedling morphological and physiological traits were analysed. The study was carried out with five populations from different geographical areas and covering an aridity gradient. Seedling morphological traits (height and total leaf area) were analyzed during the first growing year. Physiological traits (net photosynthesis, stomatal conductance, leaf transpiration, and intrinsic water-use efficiency) were analysed at different air temperatures during spring, summer, and winter months, and in response to water stress. There were significant correlations among the considered acorn (volume, fresh mass) and seedling traits. Differences in growth and physiological traits among the considered populations were found. The larger differences in the growth parameters were observed during the first growing season, and they could be justified by the significant differences among acorn size. On the contrary, the physiological response to air temperature and aridity was more related to the geographical origin of the considered populations than to acorn size. Q. ilex acorn and seedling traits more tolerant to drought might have a high potential for vegetation recovery in afforestation projects and restoration programmes particularly under water-limited environments or in degraded areas. and A. Bonito ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2714. Relationship between carbon and nitrogen metabolisms in photosynthesis. The role of photooxidation processes
- Creator:
- Chikov, V. and Bakirova, G.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- alanine, aspartate, glycine, glycollate, malate, nitrate, serine, sugars, Triticum aestivum, urea, and wheat
- Language:
- Multiple languages
- Description:
- 14CO2 uptake in leaves of wheat plants (Triticum aestivum L.) fertilized by urea or Ca(NO3)2 (25 mol m-3) was investigated. The Warburg effect (inhibition of 14CO2 uptake by oxygen) under 0.03 vol. % CO2 concentration was observed only in non-fertilized plants. Under 0.03 vol. % CO2, the Warburg antieffect (stimulation of 14CO2 uptake by oxygen) was detected only in plants fertilized by Ca(NO3)2. Under saturating CO2 concentration (0.30 vol. %), the Warburg antieffect was observed in all variants. Under limitation of ribulose-1,5-bisphosphate carboxylase/oxygenase activity (0.30 vol. % CO2 + 1 vol. % O2), the rate of synthesis of glycollate metabolism products decreased in control and urea-fertilized plants but was enhanced in nitrate-fed plants. Hence, there was an activation of glycollate formation via transketolase reaction in fertilized plants, and the products of nitrate reduction function were oxidants in nitrate-fertilized plants whereas the superoxide radical played this role in urea-fertilized plants. and V. Chikov, G. Bakirova.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2715. Relationship between contents of chlorophyll (a+b) (SPAD values) and nitrogen of some temperate grasses
- Creator:
- Gáborčík, N.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- cultivar differences, Festuca, Lolium, and species differences
- Language:
- Multiple languages
- Description:
- In a field experiment the chlorophyll (a+b) (SPAD readings) and nitrogen contents of three grass species (Festuca arundinacea Schreb., Lolium perenne L., and Lolium multiflorum Lam.) and three intergeneric hybrids of Festuca pratensis Huds. × Lolium multiflorum Lam. and Festuca arundinacea Schreb. × Lolium multiflorum Lam. were measured. Close relationships were found between SPAD readings and nitrogen leaf content (r2 = 0.873** 0.491** and 0.938**) for the 1st, 2nd, and 3rd cut, respectively. SPAD readings and N contents were closely correlated (r = 0.836**) confirming that SPAD measurements could be used in grass selection and/or breeding for high N concentration in herbage.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2716. Relationship between flavonoids and photoprotection in shade-developed Erigeron breviscapus transferred to sunlight
- Creator:
- Zhou, R., Su, W. H., Zhang, G. F., Zhang, Y. N., and Guo, X. R.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, chlorophyll fluorescence, flavonoid, phenolics, protection, photodamage, 2, and 581
- Language:
- Multiple languages
- Description:
- Flavonoids are thought to participate in protection of the photosynthetic apparatus against photoinhibition under excessive light. Flavone glycoside, scutellarin, is a main active ingredient extracted from Erigeron breviscapus, the plant used in Chinese medicine. Shade-developed leaves of E. breviscapus were transferred from shade to full sunlight to quantify a relationship between the concentration of leaf scutellarin and tolerance to high radiation stress or the recovery from photoinhibition. The maximal quantum yield of PSII photochemistry showed a diurnal fluctuation in both shaded and sunlit leaves throughout the day. It indicated dynamic photoinhibition in the leaves of Erigeron, i.e., higher photoinhibition at solar noon and lower one in the morning and late afternoon. The sun-developed leaves reached the higher scutellarin content and values of nonphotochemical quenching coefficient with a lower degree of photoinhibition than the shade-developed leaves. When the shade-developed leaves were transferred to full sunlight, the content of scutellarin was declining continuously for 10 d and then was increasing for 15 d. After 50 d, all leaves became the sun-developed leaves with their scutellarin contents of about 138.5 ± 5.2 mg g-1(dry mass, DM) which was significantly higher than that of the shade-developed leaves [107.8 ± 9.8 mg g-1(DM)]. During acclimatization, the degree of photoinhibition was negatively correlated with the scutellarin content. Our results demonstrated a synchronous fluctuation between the flavonoid content and degree of protection against photoinhibition., R. Zhou, W. H. Su, G. F. Zhang, Y. N. Zhang, X. R. Guo., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2717. Relationship between leaf soluble protein content and net photosynthetic rate in tropical deciduous tree species
- Creator:
- Naidu, C.V. and Swamy, P.M.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- Leaf protein content and net photosynthetíc rate (P^) were estimated at monthly intervals in seven tropical deciduous tree species, námely Chukrasia tabularis, Dolichandrone atrovirens, Eugenia Jambolana, Gmelina arborea, Lannea coromandelica, Terminalia arjuna and Terminalia bellerica firom September 1990 to August 1991. Among the seven tree species examined, Terminalia arjuna exhibited a significant positive correlation (r = 0.81; p < 0.05) between leaf protein content and while in others it was found insignificant.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2718. Relationship between net photosynthesis and leaf respiration in Mediterranean evergreen species
- Creator:
- Gratani, L., Varone, L., and Catoni, R.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Arbutus, Cistus, Myrtus, Phillyrea, Q10, Quercus, seasonal course, and temperature
- Language:
- Multiple languages
- Description:
- The relationship between net photosynthetic (PN) and leaf respiration (R) rates of Quercus ilex, Phillyrea latifolia, Myrtus communis, Arbutus unedo, and Cistus incanus was monitored in the period February 2006 to February 2007. The species investigated had low R and PN during winter, increasing from March to May, when mean air temperature reached 19.2 °C. During the favourable period, C. incanus and A. unedo had a higher mean PN (16.4±2.4 µmol m-2 s-1) than P. latifolia, Q. ilex, and M. communis (10.0±1.3 µmol m-2 s-1). The highest R (1.89±0.30 µmol m-2 s-1, mean of the species), associated to a significant PN decrease (62 % of the maximum, mean value of the species), was measured in July (mean R/PN ratio 0.447±0.091). Q10, indicating the respiration sensitivity to short-term temperature increase, was in the range 1.49 to 2.21. Global change might modify R/PN determining differences in dry matter accumulation among the species, and Q. ilex and P. latifolia might be the most favoured species by their ability to maintain sufficiently higher PN and lower R during stress periods. and L. Gratani, L. Varone, R. Catoni.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2719. Relationship between net photosynthesis and tuber yield in potato grown under short days
- Creator:
- Singh, Lallan, Basu, P.S., and Sukumaran, N.P.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- Field studies with segregating populations under short days showed a significant positive correlation between tuber yield and the light-saturated net photosynthetic rate (Fn) in the 4th leaf from the top, at the tuber formation stage, in two seasons. The leaf area per plant {A) at this stage and also at the tuber bulking stage had a significant positive correlation with tuber yield. The product of PN and A also showed a significant positive correlation with tuber yield at both of these stages, a stronger one than that between tuber yield and A at the tuber formation stage.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2720. Relationship between photosynthesis and photorespiration in field-grown wheat leaves
- Creator:
- Di Marco, G., Iannelli, M.A., and Loreto, F.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- Simultaneous measurements of net photosynthetic rate {P^ and fluorescence were taken on flag leaves of fíeld-grown wheat {Triíicum aestivum L., Thlicum durum L.) from anthesis to senescence. By using leaf discs inaintained in saturating CO2 in tlie O2 electrode we found that the electron transport measured by fluorescence, and that calculated from O2 evolution rate were similar througliout the experimental period, which indicated that fluorescence might be ušed to measure the linear electron transport rate. In field measurements on intact attached leaves, the electron transport rate declined less than during leaf senescence, Measurements taken in the aftemoon indicated that the electron transport remained constant during the day while slightly decreased. Thus, in fíeld-grown wheat leaves photoinhibition was not a relevant phenomenon. When the alternativě electron routes were negligible, the increasing discrepancy between Pn and the electron transport during leaf senescence could be explained by an increment in photorespiration rate (Pp), The change of oxygenation to carboxylation ratio (Vq/Vj,) might be caused by increasing resistances to CO2 diffusion in the leaf CO2 lost through photorespiration was about half of that fixed with Pn in the sun-exposed leaves. Yet Pp was lower in the basal part of leaves which mostly grew in shade. Fluorescence coupled with gas exchange proved to be a useful method for evaluation of the photorespiratory losses in field conditions.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public