Number of results to display per page
Search Results
3632. Photosynthesis, transpiration, and water use efficiency of Caragana microphylla, C. intermedia, and C. korshinskii
- Creator:
- Ma, C. C., Gao, Y. B., Guo, H. Y., and Wang, J. L.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- geographic distribution, growth and development, morphological structure, physio-ecological adaptation, water deficit, and water regime
- Language:
- Multiple languages
- Description:
- In the order C. microphylla - C. intermedia - C. korshinskii, compensation irradiance, saturation irradiance, and optimum temperature for photosynthesis increased, net photosynthetic rate (PN) at low irradiance and low temperature decreased, optimum air humidity decreased, and PN at low air humidity increased. Daily cumulative value of PN increased while daily cumulative value of transpiration (E) decreased, and hence water use efficiency (WUE =PN/E) increased. Diurnal course of PN of C. microphylla was a double-peak curve, but the second peak in the curves of C. intermedia and C. korshinskii was not visible. These physiological characteristics are biological basis for the geographical distribution of these three Caragana species, and are in relation to water conditions of their habitats and distinctiveness in leaf hair of plant. and C. C. Ma ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3633. Photosynthesis, transpiration, and water use efficiency of Leymus dasystachys on the Hunshandake desert
- Creator:
- Wang, R. Z., Liu, X. Q., Xing, Q., and Bai, Y.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- dry and rainy seasons, leaf age and insertion, and stomatal conductance
- Language:
- Multiple languages
- Description:
- Net photosynthetic rate (PN), transpiration rate (E), and stomatal conductance (gs) declined from upper leaves to the lower ones during dry and rainy seasons, indicating that long-term carbon budget should take into account PN variations for different leaf types. Relatively greater PN in the dry season suggested that this species is more able to maintain higher PN under drought, but the relatively higher E in the dry season might reduce water use efficiency (PN/E) for the species. Significant correlations between PN and gs indicated that gs may be the critical factor for PN variability in the desert region. and R. Z. Wang ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3634. Photosynthesis, transpiration, and water use efficiency of two Puccinellia species on the Songnen grassland, northeastern China
- Creator:
- Wang, R. Z. and Yuan, Y. Q.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- intra- and inter-specific variations, leaf age, net photosynthetic rate, and plant and water relations
- Language:
- Multiple languages
- Description:
- The intra- and inter-specific variations in net photosynthetic (PN) and transpiration (E) rates and water use efficiency (WUE) of Puccinellia tenuiflora and Puccinellia chinampoensis leaves were compared. The two species experienced a similar habitat, but differed in leaf area, leaf colour, and nitrogen contents. Leaf PN and E for both reproductive and vegetative shoots of the two species declined with leaf age. PN for reproductive shoots was less than for vegetative shoots, but their E was greater than that of vegetative shoots in the dry season. The average PN and E for reproductive shoots of P. tenuiflora were lower than those of P. chinampoensis, but higher for vegetative shoots. and R. Z. Wang, Y. Q. Yuan.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3635. Photosynthesis, transpiration, and water use efficiency of vegetative and reproductive shoots of grassland species from north-eastern China
- Creator:
- Wang, R. Z.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- grasses, Leymus, physiological differences, plant water elations, and Puccinellia
- Language:
- Multiple languages
- Description:
- The differences in net photosynthetic rate (PN), transpiration rate (E), and water use efficiency (WUE) between the vegetative and reproductive shoots of three native grass species from the grassland of northeastern China [grey-green and yellow green populations of Leymus chinensis (Trin.) Tzvel., Puccinellia tenuiflora (Griseb) Scrib & Merr, Puccinellia chinampoensis Ohwi] were compared. The two type shoots experienced similar habitats, but differed in leaf life-span and leaf area. The leaf PN and WUE for the vegetative shoots were significantly higher than those for the reproductive shoots in the grasses, while their E were remarked lower in the dry season. Relative lower leaf PN and WUE for the reproductive shoots of grassland grasses may explain the facts of lower seed production and the subordinate role of seed in the grassland renewal in north-eastern China.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3636. Photosynthesis, water use efficiency, and δ13C in two rice genotypes with contrasting response to water deficit
- Creator:
- Pieters, A. J. and Núñez, M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- dry mass, intercellular CO2 concentration, Oryza sativa, relative water content, stomatal conductance, and transpiration rate
- Language:
- Multiple languages
- Description:
- The effects of water deficit and re-irrigation were studied in glasshouse-grown rice plants (cvs. Cimarrón and Fonaiap 2000) which differ in their susceptibility to water deficit. Relative water content decreased from >90 to 67-69 % and recovered to pre-stress values within 24 h after re-irrigation. The irradiance-saturated rate of photosynthesis (Psat), transpiration rate (E), and stomatal conductance (gs) decreased with water deficit. E and gs decreased similarly in both cultivars, but Psat was more strongly inhibited in Cimarrón than in Fonaiap 2000. Water deficit increased water use efficiency (WUET) over 2-fold in Fonaiap 2000 and by 1.5-fold in Cimarrón. The ratio of intercellular to ambient CO2 concentration (Ci/Ca) decreased in Fonaiap 2000 during mild stress but increased at severe stress. Contrarily, Cimarrón did not change Ci/Ca with water deficit. After re-irrigation Fonaiap 2000 recovered Psat to ca. 80 % of control values 24 h after re-irrigation, whereas Cimarrón recovered to 60 % of control values 48 h after re-irrigation. E and gs recovered to a lesser extent (50 %) than Psat, after 48 h of re-irrigation in both cultivars. Total aboveground and green (live) biomass were unaffected by water deficit in Fonaiap 2000 but were reduced by 21 and 40 % in Cimarrón, respectively. Dead biomass increased in stressed plants of both cultivars but to a larger extent in Cimarrón than in Fonaiap 2000. Water deficit increased δ13C in Fonaiap 2000, whereas Cimarrón was unaffected by water deficit showing lower values than those of Fonaiap 2000. δ13C was highly and linearly correlated to the ratio Ci/Ca. WUET was also significantly correlated to δ13C. and A. J. Pieters, M. Núñez.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3637. Photosynthesis, water-use efficiency and δ13C of five cowpea genotypes grown in mixed culture and at different densities with sorghum
- Creator:
- Makoi, J. H. J. R., Chimphango, S. B. M., and Dakora, F. D.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, chlorophyll, cultivars, discrimination, gas exchange, intercropping, isotope, monocropping, plant stand, species, and varieties
- Language:
- Multiple languages
- Description:
- A field experiment involving two planting densities (83,333 and 166,666 plants per ha), two cropping systems (monoculture and mixed culture) and five cowpea [Vigna unguiculata L. (Walp.)] genotypes was conducted at Nietvoorbij (33°54S, 18°14E), Stellenbosch, South Africa, to select cowpea material with superior growth and water-use efficiency (WUE). The results showed significantly higher photosynthetic rates, stomatal conductance and transpiration in leaves of plants at low density and in monoculture due to greater chlorophyll (Chl) levels relative to those at high density and in mixed culture. As a result, C concentration in leaves and the amount of C, P, K, Ca, Mg, Fe, Cu, Zn, Mn, and B accumulated in shoots at low density and under monoculture were also much higher. Even though no marked differences in photosynthetic rates were found between and among the five cowpea genotypes, leaf C concentration and shoot C, P, K, Ca, Mg, Fe, Cu, Zn, Mn, and B contents differed considerably, with Sanzie exhibiting the highest C concentration and C, P, K, Ca, Mg, Fe, Cu, Zn, Mn, and B contents in shoots, followed by Bensogla and Omondaw, while ITH98-46 and TVu1509 had the lowest shoot concentration and contents of C, P, K, Ca, Mg, Fe, Cu, Zn, Mn, and B. WUE (calculated as photosynthate produced per unit water molecule transpired) was significantly greater in plants at low density and monoculture relative to those at high density and in mixed culture. Isotopic analysis revealed significant differences in δ13C values of sorghum [Sorghum bicolor L. (Moench.)] and cowpea, with higher δ13C values being obtained for plants at low density and in monoculture relative to those at high density or in mixed culture. The five cowpea genotypes also showed significant differences in δ13C values, with Sanzie exhibiting the most negative value (i.e. low WUE) and ITH98-46, the least negative δ13C value (i.e. high WUE). Whether measured isotopically or from gas-exchange studies, sorghum (a C4 species) exhibited much higher WUE relative to cowpea (a C3 species). Both correlation and regression analyses revealed a positive relationship between WUE from gas-exchange studies and δ13C values from isotopic analysis of cowpea and sorghum shoots. and J. H. J. R. Makoi, S. B. M. Chimphango, F. D. Dakora
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3638. Photosynthesis-nitrogen relationship in a Hinoki cypress (Chamaecyparis obtusa) canopy: a comparison with Japanese cedar (Cryptomeria japonica)
- Creator:
- Kobayashi, H., Inoue, S., and Gyokusen, K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, leaf nitrogen content, photosynthetic capacity, species difference, winter depression, 2, and 58
- Language:
- Multiple languages
- Description:
- The relationship between light-saturated photosynthetic capacity (Pmax) and leaf nitrogen (N) content was investigated for one year in a 15-year-old Chamaecyparis obtusa canopy and was compared with a Cryptomeria japonica canopy previously described. The linear regression between P max and leaf N content tended to converge toward a single line segment from July to January and in May for C. obtusa. The slope of the linear regression between Pmax and leaf N content of C. obtusa was gentler than that of C. japonica. The smaller regression coefficient of C. obtusa may reflect species differences in nitrogen nutrition requirements between C. obtusa and C. japonica. A pronounced decrease in the slope of the linear regression lines due to low temperature was observed in February and March. During this period, P max of C. obtusa declined more than that of C. japonica suggesting that C. obtusa is less tolerant to low temperatures than C. japonica., H. Kobayashi, S. Inoue, and K. Gyokusen., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3639. Photosynthesis-nitrogen relationships in pioneer plants of disturbed tropical montane forest sites
- Creator:
- Quilici, A. and Medina, E.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Crotalaria anagyroides, ecological succession, nitrogen use efficiency, respiration, saccharides, specific leaf area, stomatal conductance, Verbesina turbacensis, and water use efficiency
- Language:
- Multiple languages
- Description:
- Tropical forest disturbances lead to the establishment of secondary successional plant communities constituted by light demanding species with high relative growth rate that conduct to rapid canopy closure. Two main strategies for N nutrition are: (a) mineral N acquisition in the form of NH4 and NO3, and (b) symbiotic atmospheric N2 fixation. Given the high N requirement for maximization of leaf area and radiant energy absorption, we hypothesize that contrasting strategies of N nutrition in these environments are reflected in leaf photosynthetic characteristics. We compared the N-photosynthesis relationships and carbon balance parameters per unit leaf area as they vary with age in two species with contrasting N acquisition strategies: a N2-fixer Crotalaria anagyroides HBK (Papilionoideae), and a mineral-N user Verbesina turbacensis HBK (Asteraceae). N2 fixation capacity was associated to higher specific leaf area (SLA), higher photosynthetic capacity (Pmax) per unit leaf area and leaf mass, and higher N content per unit leaf mass. The N2-fixer species showed higher slope in the relationship Pmax-N per unit leaf mass and area when compared to the leaves of non-fixer species. Moreover, the intrinsic photosynthetic N use efficiency (Pmax/N) was higher in the N2 fixer than in leaves of the non-fixer species. Changes in N due to leaf age resulted in larger changes in CO2 flux density at the leaf level in the N2-fixer species. The higher photosynthetic capacity of the N2-fixer species was mechanistically related to higher stomatal conductance, internal CO2 concentration (ci) values closer to atmospheric CO2 concentration (ca), and lower intrinsic water use efficiency than the mineral N-user species. Despite their higher Pmax per unit leaf area, total non-structural saccharides concentration was lower in mature leaves of the N2-fixer plant as compared to the non-fixer counterpart. This might be caused by the presence of a larger root sink (symbionts) stimulating saccharides export and higher diurnal respiration rates. and A. Quilici, E. Medina.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3640. Photosynthetic acclimation and leaf traits of Stipa bungeana in response to elevated CO2 under five different watering conditions
- Creator:
- Wang, H., Zhou, G. S., Jiang, Y. L., Shi, Y. H., and Xu, Z. Z.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- klimatické změny, climate changes, uhlíková bilance, výměna plynu, respirace, fluorescence chlorofylu, carbon balance, gas exchange, respiration, chlorophyll fluorescence, 2, and 581
- Language:
- Multiple languages
- Description:
- Although plant performance under elevated CO2 (EC) and drought has been extensively studied, little is known about the leaf traits and photosynthetic performance of Stipa bungeana under EC and a water deficiency gradient. In order to investigate the effects of EC, watering, and their combination, S. bungeana seedlings were exposed to two CO2 regimes (ambient, CA: 390 ppm; elevated, EC: 550 ppm) and five levels of watering (-30%, -15%, control, +15%, +30%) from 1 June to 31 August in 2011, where the control water level was 240 mm. Gas exchange and leaf traits were measured after 90-d treatments. Gas-exchange characteristics, measured at the growth CA, indicated that EC significantly decreased the net photosynthetic rate (PN), water-use efficiency, nitrogen concentration based on mass, chlorophyll and malondialdehyde (MDA) content, while increased stomatal conductance (gs), intercellular CO2 concentration (Ci), dark respiration, photorespiration, carbon concentration based on mass, C/N ratio, and leaf water potential. Compared to the effect of EC, watering showed an opposite trend only in case of PN. The combination of both factors showed little influence on these physiological indicators, except for gs, Ci, and MDA content. Photosynthetic acclimation to EC was attributed to the N limitation, C sink/source imbalance, and the decline of photosynthetic activity. The watering regulated photosynthesis through both stomatal and nonstomatal mechanisms. Our study also revealed that the effects of EC on photosynthesis were larger than those on respiration and did not compensate for the adverse effects of drought, suggesting that a future warm and dry climate might be unfavorable to S. bungeana. However, the depression of the growth of S. bungeana caused by EC was time-dependent at a smaller temporal scale., H. Wang, G. S. Zhou, Y. L. Jiang, Y. H. Shi, Z. Z. Xu., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public