Number of results to display per page
Search Results
232. The effect of CO2 enrichment on the growth of nodulated and non-nodulated isogenic types of soybean raised under two nitrogen concentrations
- Creator:
- Nakamura, T., Koike, T., Lei, T., Ohashi, K., Shinano, T., and Tadano, T.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- genetic differences, Glycine max, leaf, net photosynthetic rate, nitrogen accumulation, nitrogen use efficiency, nodule and plant dry mass, stem, and root
- Language:
- Multiple languages
- Description:
- To find the effects of CO2 enrichment on plant development and photosynthetic capacity of nodulated (line A62-1) and non-nodulated (line A62-2) isogenic lines of soybean (Glycine max Merr.), we examined the interactions among two CO2 treatments (36±3 Pa = AC and 70±5 Pa = EC), and two nitrogen concentrations [0 g(N) m-2(land area) = 0N; 30 g(N) m-2(land area) = 30N]. Nodules were found in both CO2 treatments in 0N of A62-1 where the number and dry mass of nodules increased from AC to EC. While the allocation of dry mass to root and shoot and the amount of N in each organ did not differ between the growth CO2 concentrations, there was larger N allocation to roots in 0N than in 30N for A62-2. The CO2-dependence of net photosynthetic rate (PN) for A62-1 was unaffected by both CO2 and N treatments. In contrast, the CO2-dependence of PN was lower in 0N than in 30N for A62-2, but it was independent of CO2 treatment. PN per unit N content was unaffected by CO2 concentrations. The leaf area of both soybean lines grown in 30N increased in EC. But in 0N, only the nodulated A62-1 showed an increase in leaf area in EC. Nitrogen use efficiency of plants, NUE [(total dry mass of the plant)/(amount of N accumulated in the plant)] in 30N was unaffected by CO2 treatments. In 0N, NUE in EC was lower than in AC in A62-1, and was higher than that at AC in A62-2. Hence, the larger amount and/or rate of N fixation with the increase of the sink-size of symbiotic microorganisms supplied adequate N to the plant under EC. In EC, N deficiency caused the down-regulation of the soybean plant. and T. Nakamura ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
233. The effect of drought on photosynthesis in two epiphytic and two terrestrial tropical fern species
- Creator:
- Zhang, Q., Chen, J.-W., Li, B.-G., and Cao, K.-F.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Asplenium, chlorophyll fluorescence, Microsorium, Neottopteris, net photosynthetic rate, Paraleptochilus, physiological recovery, relative water content, stomatal conductance, and water conservation strategy
- Language:
- Multiple languages
- Description:
- Water-withholding for 5 to 7 weeks and subsequent re-watering were made on potted plants of two epiphytic (E) and two terrestrial (T) fern species, which were collected from a seasonal tropical rainforest and had been grown in a screenhouse with 5 % irradiance for 4 months. During the water stress, the two E species completely closed stomata when frond relative water content (RWC) reached about 70 % with fairly constant maximum photochemistry efficiency (Fv/Fm), while the two T species kept partial stomata opening until RWC reached 45 % and reduction in Fv/Fm at the late stage. Also, chlorophyll content as indicated by a spectral reflectance index was gradually reduced in three species. Physiological recovery was completed after 3-d re-watering for the E species, which was more rapid than for the T species. The gas exchange measurements and regression analyses indicated higher photosynthetic water use efficiency in the E species than in the T species. and Q. Zhang ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
234. The effect of leaf age on gas exchange and malate accumulation in C3-CAM plant Marrubium frivaldszkyanum (Lamiaceae)
- Creator:
- Markovska, Y. K. and Dimitrov, D. S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- C3-CAM shift, Crassulacean Acid Metabolism, leaf expansion, net photosynthetic rate, transpiration rate, and water use efficiency
- Language:
- Multiple languages
- Description:
- For the first time the expression of C3 and CAM in the leaves of different age of Marrubium frivaldszkyanum Boiss, is reported. With increasing leaf age a typical C3 photosynthesis pattern and high transpiration rate were found. In older leaves a shift to CAM occurred and the 24-h transpiration water loss decreased. A correlation was established between leaf area and accumulation of malate. Water loss at early stages of leaf expansion may be connected with the shift to CAM and the water economy of the whole plant. and Y. K. Markovska, D. S. Dimitrov.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
235. The effect of phyllode temperature on gas exchange and chlorophyll fluorescence of Acacia mangium
- Creator:
- Yu, Hun and Ong, Bee-Lian
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- dark respiration rate, net photosynthetic rate, photochemical and non-photochemical quenching, photosystem 2 efficiency, stomatal conductance, and transpiration rate
- Language:
- Multiple languages
- Description:
- The optimum temperature for photosynthetic CO2 assimilation of A. mangium phyllodes was 30-32 °C. Photosystem 2 (PS 2) exhibited high tolerance to high temperature. Gas exchange and the function of PS2 of A. mangium were adapted to the temperature regime of the tropical environment and this might be the contributing factor to their fast growth under tropical conditions. and Hua Yu, Bee-Lian Ong.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
236. The effects of intermittent flooding on seedlings of three forest species
- Creator:
- Anderson, P. H. and Pezeshki, S. R.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- bottomland forests, leaf conductance, net photosynthetic rate, Quercus michauxti, Quercus nuttallii, and Taxodium distichum
- Language:
- Multiple languages
- Description:
- Under greenhouse conditions, seedlings of three forest species, baldcypress (Taxodium distichum), nuttall oak (Quercus nuttallii), and swamp chestnut oak (Quercus michauxii) were subjected to an intermittent flooding and subsequent physiological and growth responses to such conditions were evaluated. Baldcypress showed no significant reductions in stomatal conductance (gs) or net photosynthetic rate (PN) in response to flood pulses. In nuttall oak seedlings gs and PN were significantly decreased during periods of inundation, but recovered rapidly following drainage. In contrast, in swamp chestnut oak gs was reduced by 71.8 % while PN was reduced by 57.2 % compared to controls. Baldcypress displayed no significant changes in total mass while oak species had significantly lower leaf and total mass compared to their respective controls. Thus baldcypress and nuttall oak showed superior performance under frequent intermittent flooding regimes due to several factors including the ability for rapid recovery of gas exchange soon after soil was drained. In contrast, swamp chestnut oak seedlings failed to resume gas exchange functions after the removal of flooding. and P. H. Anderson, S. R. Pezeshki.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
237. The influence of increased solar UV-B radiation on magnesium-deficient cowpea seedlings: Changes in the photosynthetic characteristics
- Creator:
- Premkumar, A. and Kulandaivelu, G.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll, chlorophyll fluorescence, induction, chloroplast proteins, CO2 uptake, net photosynthetic rate, photochemical activities, and Vigna unguiculata
- Language:
- Multiple languages
- Description:
- The influence of increased solar UV-B radiation on the photosynthetic characteristics in cowpea seedlings (Vigna unguiculata) grown at optimal (Mgs) and low (Mgd) Mg levels were studied. Both higher UV-B and Mgd treatments caused significant drops of photochemical activities and net CO2 uptake rates (PN). Yet the UV-B-induced decrease in the photosynthetic efficiency was lesser in Mgd seedlings. The leaf Chl a fluorescence measurements proved that after receiving an enhanced UV-B radiation these seedlings showed a significant enhancement in their variable parts. The PSM oscillation of slow fluorescence kinetics was remarkably altered by both treatments. The PN also followed a typical inhibitory pattern as seen in photochemical activities. Concentrations of several chloroplast proteins in trifoliate leaves were significantly reduced by Mgd treatment and unaffected by the other two treatments. Whereas the contents of 43-47 kDa polypeptides in primary leaves were markedly reduced with a maximal effect in Mgd seedlings, no major difference was noted for combined stress. and A. Premkumar, G. Kulandaivelu.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
238. The photosynthesis and chlorophyll a fluorescence in seedlings of Kandelia candel (L.) Druce grown under different nitrogen and NaCl controls
- Creator:
- Kao, Wen-Yuan and Tsai, Hung-Chieh
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- mangrove, net photosynthetic rate, photoinhibition, photoprotection, salinity, and stomatal conductance
- Language:
- Multiple languages
- Description:
- Kandelia candel (L.) Druce is the dominant mangrove species on the west coast of northern Taiwan. We have measured the net photosynthetic rate (PN) and chlorophyll (Chl) a fluorescence of seedlings grown at combinations of two nitrogen (0.01 and 0.1 mM) and two NaCl (250 and 430 mM NaCl) controls. With the same nitrogen level, seedlings grown at higher salinity (HS) had a significantly lower PN and stomatal conductance (gs) than those at lower salinity (LS). An increase in nitrogen availability significantly elevated PN and gs of the LS-grown seedlings. Compared to dark adapted leaves, the maximum quantum yield of photosystem 2 (PS2) (Fv/Fm) of leaves exposed to PFDs of 1200 and 1600 µmol m-2 s-1 for 2 h was significantly reduced. The degree of Fv/Fm reduction differed among leaves of the four types of treated plants. Chl fluorescence quenching analysis revealed differences among the examined plants in coefficients of non-photochemical and photochemical quenching. and Wen-Yuan Kao, Hung-Chieh Tsai.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
239. The photosynthetic efficiency of some elite rice hybrids and restorers
- Creator:
- Baig, M. J., Swain, P., and Murty, K. S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- cultiivars, growth stages, heterosis, leaf area index, maintenance respiration, net photosynthetic rate, and Oryza sativa
- Language:
- Multiple languages
- Description:
- At the vegetative growth stage (40 d), the mean photosynthetic rate (PN) and canopy photosynthesis (PN × LAI) in F1 hybrids and their parents were similar, whereas the maintenance respiration rate (RM) was considerably higher and PN/RM lower in the F1 hybrids than in the parents. Yet at the flowering stage, the hybrids showed higher PN and PN × LAI values, while RM and PN/RM were similar in both. A specific F1 hybrid like IR 62829A×Vajram showed high readings in PN, PN/RM, and PN × LAI at the flowering stage, while IR 62829A×Swarna followed by IR 62829A×Vajram had high values 40 d after planting. The parents Swarna and Vajram, although moderate in PN, had the highest PN × LAI at the flowering stage due to a greater LAI. and M. J. Baig, P. Swain, K. S. Murty.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
240. The responses of photosynthetic rate and stomatal conductance of Fraxinus rhynchophylla to differences in CO2 concentration and soil moisture
- Creator:
- Zhang, S. Y., Zhang, G. C., Liu, X., and Xia, J. B.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, CO2 response, net photosynthetic rate, photorespiration, relative water content, soil moisture, 2, and 581
- Language:
- Multiple languages
- Description:
- The photosynthetic parameters in leaves of three-year-old seedlings of Fraxinus rhynchophylla L. were studied under different soil water conditions and CO2 concentrations ([CO2]) with a LI-COR 6400 portable photosynthesis system. The objective was to investigate the response of photosynthesis and stomatal conductance (gs) to various [CO2] and soil water conditions, and to understand the adaptability of F. rhynchophylla to such conditions. The results showed that the soil water content (RWC) required to maintain high photosynthetic productivity in F. rhynchophylla was 49.5-84.3%; in this range, net photosynthetic rate (PN) rose with [CO2] increasing from 500 to 1,400 μmol mol-1. Outside this RWC range, PN decreased significantly. The apparent maximum photosynthetic rate (Pmax,c) and carboxylation velocity (Vc) increased with increasing RWC and remained relatively high, when RWC was between 49.5 and 96.2%. CO2 compensation points and photorespiration rate exhibited a trend opposite to that of Pmax,c and Vc, indicating that moderate water stress was beneficial for increasing plant assimilation, decreasing photorespiration, and increasing production of photosynthates. gs declined significantly with increasing [CO2] under different water supplies, but the RWC range maintaining high gs increased. gs reached its maximum, when RWC was approximately 73% and then decreased with declining RWC. The maximal gs was found with increasing RWC. Thus, based on photosynthetic characteristics in artificial, vegetation construction in semiarid loess hill and gully area, F. rhynchophylla could be planted in habitats of low soil water content. and S. Y. Zhang ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public