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732. Diurnal changes in photosynthesis, sugars, and nitrogen of wheat and mungbean grown under elevated CO2 concentration
- Creator:
- Srivastava, A. C., Khanna, Y. P., Meena, R. C., Pal, Madan, and U. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- net photosynthetic rate, non-protein nitrogen, non-structural sacharides, and protein nitrogen
- Language:
- Multiple languages
- Description:
- The diurnal changes in leaf net photosynthetic rate (PN) and sugar and nitrogen contents in wheat [Triticum aestivum (L.) cv. HD 2285] and mungbean [Vigna radiata (L.) Wilczek cv. PS 16] were analysed under ambient, AC [350±25 µmol mol-1] and elevated, EC [600±50 µmol mol-1] CO2 concentrations. In both mungbean and wheat PN of AC- and EC-grown plants compared at the same CO2 concentration showed that PN was higher under EC. However, increased PN in EC-plants declined in the afternoon and approached PN of AC-plants. Depression in PN, however, was less in mungbean compared with the large depression in wheat. Greater down regulation of PN in wheat was associated with the accumulation of large amount of sugars and low nitrogen content in wheat leaves. Mungbean leaves accumulated mostly starch under EC and the difference in N content in AC- and EC-plants was relatively less than in wheat. and A. C. Srivastava ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
733. Diurnal changes of gas exchange, chlorophyll fluorescence, and stomatal aperture of hybrid poplar clones subjected to midday light stress
- Creator:
- Zhang, Shouren and Gao, Rongfu
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- intercelullar CO2 concentration, irradiance, net photosynthetic rate, Populus, and stomatal aperture
- Language:
- Multiple languages
- Description:
- Diurnal changes in net photosynthetic rate (PN), chlorophyll (Chl) fluorescence, and stomatal aperture of several hybrid poplar clones subjected to midday light stress were measured in July and August of 1996. Midday depression of PN, photosystem 2 (PS2) efficiency, stomatal conductance (gs), and stomatal aperture was observed in all clones, though at differing rates among them. Non-uniform stomatal closure occurred at noon and at other times, requiring a modification of intercellular CO2 concentration (C1). A linear relationship was found between gs and stomatal aperture. More than half of the photons absorbed by PS2 centre dissipated thermally when subjected to light stress at noon. There was a linear relationship between the rate of PS2 photochemical electron transport (PxPFD) and PN. There was a consensus for two fluorescence indicators (1 - qP/qN and (Fm' - F)/Fm') in assessment of susceptibility of photoinhibition in the clones. According to PN, Chl fluorescence, and stomatal aperture, we conclude that midday depression of photosynthesis can be attributed to both stomatal and non-stomatal limitations. and Shouren Zhang, Rongfu Gao.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
734. Diurnal course of gaseous exchange and leaf water potential in relation to substrate-heating of Gerbera
- Creator:
- Romero-Aranda, R. and Martinez, P. F.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- The effects of substrate-heating on gas exchange and leaf water potential of gerbera {Gerbera jamesonii H. Bolus ex Hook.) cv. Maria grown in rockwool as substráte were studied under a plastic greenhouse. Measurements of net photosynthetic rate (Pn), stomatal conductance to water vapour {g^, leaf to air vapour pressure difference (VPD), and leaf water potential ('P) were made along the day, at different dates, during two winter seasons. and were higher in plants grown with substrate-heating than in control plants. Control plants without substrate-heating showed higher VPD values. T' was generally more negative for the control plants. These differences may be ascribed to differences in root activity and/or root development, which are related to the temperature of the substráte.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
735. Diurnal course of photochemical activity of winter-adapted Scots pine at subzero temperatures
- Creator:
- Šiffel, P. and Šantrůček, J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, cold adaptaation, diurnal changes, photosystem 2, Pinus sylvestris L., and quantum yield
- Language:
- Multiple languages
- Description:
- The photochemical activity of native Central Siberian Scots pine trees (Pinus sylvestris L) was estimated from the middle of February to the middle of March 2001. We measured chlorophyll (Chl) fluorescence in attached intact needles from trees located approx. 30 km west of the Yenisey river (60°44'N, 89°09'E) near the village of Zotino. In this period, the air temperature varied between -39 °C and +7 °C. At temperatures below -10 °C, P. sylvestris needles did not exhibit any variable Chl fluorescence during the daylight period. During the night, however, the effective quantum yield of photosystem 2 (PS2) photochemistry, Φ2 [Φ2 = (Fm' - Ft)/Fm'), increased from values near zero to values between 0.05 and 0.20 depending on the needle temperature and sample investigated. The increase started soon after dusk and lasted for 3-6 h depending on the temperature. A faster increase of Φ2 was found for temperatures around -16 °C, and lower rates occurred at lower temperatures. Irrespective of the temperature, Φ2 decreased rapidly to near zero values at dawn, when the photosynthetic photon flux density increased to about 1-5 µmol m-2 s-1, and remained near zero throughout the day. At temperatures higher than -10 °C, the diurnal decrease and the nocturnal increase of Φ2 were less distinct or disappeared completely. Hence the winter-adapted Scots pine maintains some photochemical activity of PS2 even at extremely cold temperatures. The capacity of photochemical reactions below -10 °C is, however, very limited and PS2 photochemistry is saturated by an extremely low irradiance (less than 5 µmol m-2 s-1). and P. Šiffel, J. Šantrůček.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
736. Diurnal course of quercetin, rutin and phioridzin effect on the activity of the Benson-Calvin cycie 1. Glyceraldehyde-3-phosphate dehydrogenase complex
- Creator:
- Nazarova, G.N., Muzafarov, E.N., and Lyubimov, V.Yu.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- Quercetin, rutin and phioridzin inhibited the activity of glyceraldehyde-3-phosphate dehydrogenase (GPD) complex from spinách leaves. At a concentiation of 5 X 10'5 M they decreased the rate of 3-phosphoglycerate (PGA) leduction by 90, 50- 80 and 30-40 % , respectively. The activity of the effectors depended on the tiine of isolation of enzymes and the corresponding level of endogenic phenolic compounds. To estimate the effect of the last factor, the enzj^e preparation was obtained in the presence and in the absence of insoluble polyvinylpyrrolidone (Polyciar AT). Using rutin it was shown that in the absence of endogenic phenols the inhibition of PGA reduction was decreased as compared with the variant without Polyciar AT. The effect of rutin was constant during the day. On the basis of data obtained the flavonoids are supposed to inhibit the Benson-Calvin cycie at its reducing stage; this effect may be cooperative and depend on quantitative and qualitative content of endogenic phenolic compounds.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
737. Diurnal cycle of chlorophyll fluorescence in Phalaenopsis
- Creator:
- Pollet, B., Steppe, K., van Labeke, M.-C., and Lemeur, R.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Crassulacean Acid Metabolism (CAM), irradiance, photosynthesis, and temperature
- Language:
- Multiple languages
- Description:
- Chlorophyll (Chl) fluorescence of warm day/cool night temperature exposed Phalaenopsis plants was measured hourly during 48 h to study the simultaneous temperature and irradiance response of the photosynthetic physiology. The daily pattern of fluorescence kinetics showed abrupt changes of photochemical quenching (qP), non-photochemical quenching (NPQ) and quantum yield of photosystem II electron transport (ΦPSII) upon transition from day to night and vice versa. During the day, the course of ΦPSII and NPQ was related to the air temperature pattern, while maximum quantum efficiency of PSII photochemistry (Fv/Fm) revealed a rather light dependent response. Information on these daily dynamics in fluorescence kinetics is important with respect to meaningful data collection and interpretation. and B. Pollet ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
738. Diurnal fluctuations in photochemical activities of chloroplasts in field grown Cyamopsis tetragonoloba seedlings
- Creator:
- Lingakumar, K. and Kulandaivelu, G.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, photochemical activities, and photosystems 1 and 2
- Language:
- Multiple languages
- Description:
- In field-grown Cyamopsis seedlings, distinct changes were found in the rates of photosystems (PS) 2 and 1 activities at different time of the day. Maximum PS2 activity was at around 11:00 h and decreased thereafter. On the contrary, PS1 activity continued to increase up to 14:00 h and declined in evening hours. Significant energy transfer from PS2 to PS1 was evident during the morning and evening hours of the day whereas a slow excitation of PS2 and energy transfer was favoured during noon hours. and K. Lingakumar, G. Kulandaivelu.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
739. Diurnal gas exchange and superior resources use efficiency of typical C4 species in Hunshandak Sandland, China
- Creator:
- Niu, S. L., Jiang, G. M., Li, Y. G., Gao, L. M., and Liu, M. Z.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- adaptation to arid environment, Agriophyllum, C3 species, Leymus, photosynthetic nitrogen use efficiency, stomatal conductance, transpiration rate, and water use efficiency
- Language:
- Multiple languages
- Description:
- Net photosynthetic rate (PN), transpiration rate (E), stomatal conductance (gs), leaf water potential (ψleaf), leaf nitrogen content, and photosynthetic nitrogen use efficiency (PNUE) were compared between a typical C4 plant, Agriophyllum squarrosum and a C3 plant, Leymus chinensis, in Hunshandak Sandland, China. The plant species showed different diurnal gas exchange patterns on June 12-14 when photosynthetic photon flux density (PPFD), air temperature (Tair), and water potential were moderate. PN, E, and gs of A. squarrosum showed distinct single peak while those of L. chinensis were depressed at noon and had two peaks in their diurnal courses. Gas exchange traits of both species showed midday depression under higher photosynthetic photon flux density (PPFD) and T air when Ψleaf was significantly low down on August 6-8. However, those of A. squarrosum were depressed less seriously. Moreover, A. squarrosum had higher PN, Ψleaf, water use efficiency (WUE), and PNUE than L. chinensis. Thus A. squarrosum was much more tolerant to heat and high irradiance and could utilise the resources on sand area more efficiently than L. chinensis. Hence species like A. squarrosum may be introduced and protected to reconstruct the degraded sand dunes because of their higher tolerance to stress and higher resource use efficiency. and S. L. Niu ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
740. Diurnal oscillation in the intercellular CO2 concentration of spring wheat under the semiarid conditions
- Creator:
- Deng, Xi-ping, Shan, Lun, Ma, Yong-qing, and Inanaga, Shinobu
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- net photosynthetic rate, soil and athmospheric drought, stomatal conductance, and Triticum aestivum
- Language:
- Multiple languages
- Description:
- Yields of wheat in semiarid and arid zones are limited by drought, and water condition is very important at each stage of development. Studies carried out at Loess Plateau in the northwestern part of China indicated that yield of spring wheat (Triticum aestivum L.) cv. Dingxi 81-392 was reduced by 41% when subjected to water stress. The effects of two water regimes on net photosynthetic rate (PN), stomatal conductance (gs), and intercellular CO2 concentration (Ci) were investigated at the jointing, booting, anthesis, and grain filling stages. Low soil moisture in comparison to adequate one had invariably reduced PN during the diurnal variations at the four growth stages. PN and gs in both soil moisture regimes was maximally reduced at midday. Ci and the stomatal limitation fluctuated remarkably during photosynthesis midday depression processes, especially at the grain filling stage. Hence atmospheric drought at midday was one of the direct causes inducing stomata closure and the gs depression, but it was beneficial for maintaining stable intrinsic water use efficiency. Fluctuation in Ci implicated that non-stomatal limitation also plays an important role during the period of photosynthesis midday depression. Consequently stomatal and/or non-stomatal limitation are the possible cause of the midday photosynthesis decline. and Xi-ping Deng ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public