Number of results to display per page
Search Results
2622. Gas exchange responses to CO2 concentration instantaneously elevated in flag leaves of winter wheat cultivars released in different years
- Creator:
- Liu, H. Q., Jiang, G. M., Zhang, Q. D., Sun , J. Z., Guo, R. J., Gao, L. M., Bai, K. Z., and Kuang, T. Y.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Ci, Ci/Ca, net photosynthetic rate, stomatal conductance, water use efficiency, and transpiration rate
- Language:
- Multiple languages
- Description:
- Three winter wheat (Triticum aestivum L.) cultivars, representatives of those widely cultivated in Beijing over the past six decades, were grown in the same environmental conditions. Net photosynthetic rate (PN) per unit leaf area and instantaneous water use efficiency (WUE) of flag leaves increased with elevated CO2 concentration. With an increase in CO2 concentration from 360 to 720 µmol mol-1, PN and WUE of Jingdong 8 (released in 1990s and having the highest yield) increased by 173 and 81 %, while those of Nongda 139 (released in 1970s) increased by 88 and 66 %, and Yanda 1817 (released in 1945, with lowest yield) by 76 and 65 %. Jingdong 8 had the highest PN and WUE values under high CO2 concentration, but Yanda 1817 showed the lowest PN. Stomatal conductance (gs) of Nongda 139 and Yanda 1817 declined with increasing CO2 concentration, but gs of Jingdong 8 firstly went down and then up as the CO2 concentration further increased. Intercellular CO2 concentration (Ci) of Jingdong 8 and Nongda 139 increased when CO2 concentration elevated, while that of Yanda 139 increased at the first stage and then declined. Jingdong 8 had the lowest Ci of the three wheat cultivars, and Yanda 1817 had the highest Ci value under lower CO2 concentrations. However, Jingdong 8 had the highest PN and lowest Ci at the highest CO2 concentration which indicates that its photosynthetic potential may be high. and H. Q. Liu ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2623. Gas exchange, growth, and antioxidant activity in sugarcane under biological nitrogen fixation
- Creator:
- Medeiros, C. D., Oliveira, M. T., Rivas, R., Baldani, J. I., Kido, E. A., and Santos, M. G.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, biomass, mineral nutrition, oxidative stress, photosynthesis, reactive oxygen species, 2, and 58
- Language:
- Multiple languages
- Description:
- The aim of this study was to characterize the key physiological aspects of three sugarcane cultivars (RB92579, RB867515 and RB872552) under biological nitrogen fixation (BNF). Plants were generated in tubes containing aseptic substrates and these plants were transferred to pots containing washed sand, but watered with a mineral fertilizer, and inoculated with a mixture of five diazotrophic bacteria three times at seven-day intervals. Under BNF, all of the cultivars contained half of their total leaf nitrogen content and 50% less shoot dry mass. The leaves of plants under BNF showed approximately 65% less of the total protein content (TP). The gas-exchange control plants had twice the CO2 assimilation rates than the BNF plants. The activity of superoxide dismutase (SOD) and ascorbate peroxidase (APX) was increased in all cultivars under BNF when compared with the control; thus, the content of hydrogen peroxide (H2O2) was also increased in these plants. The results of this study indicate that after acclimatization, the inoculation of young plants from tissue culture with diazotrophic bacteria could supply approximately 50% of their nitrogen requirement., C. D. Medeiros ... [et al.]., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2624. Gas exchange, leaf structure, and hydraulic features in relation to sex, shoot form, and leaf form in an evergreen shrub Sabina vulgaris in the semi-arid Mu Us Sandland in China
- Creator:
- He, W.-M., Zhang, X.-S., and Dong, M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- coefficient of water loss, leaf anatomy, photosynthesis, Sabina vulgaris, tissue density, transpiration, and water use efficiency
- Language:
- Multiple languages
- Description:
- We examined differences in net photosynthetic rate (PN), transpiration rate (E), water use efficiency (WUE), ratio of substomatal to atmospheric CO2 concentration (Ci/Ca), cuticle thickness (CT), epidermis cell size (ECS), mesophyll cell size (MCS), vascular bundle size (VBS), tissue density (TD), and coefficient of water loss (k) in Sabina vulgaris as related to sex, shoot form, and leaf form. PN, E, WUE, Ci/Ca, MCS, VBS, and k varied with sex, whereas CT, ECS, and TD did not. These differences in physiology and anatomy between the female and male plants may be closely related with their reproduction behaviour. PN, E, Ci/Ca, CT, ECS, MCS, and VBS were significantly smaller in the erect shoots than in the prostrate shoots, WUE was just opposite; TD and k did not vary with shoot form. These changes in physiology with shoot form indicate that erect shoots may be more tolerant of water stress than prostrate shoots. PN, E, Ci/Ca, TD, and k were significantly greater in the spine leaves than in the scale leaves, whereas WUE, CT, ECS, MCS, and VBS followed the opposite trends. The changes in physiology and anatomy with leaf form suggest that scale leaves have higher drought-resistant and water-holding capacities than spine leaves. Measurements of field gas exchange showed that three-year-old seedlings had lower drought-resistance and higher water loss than five-year-old seedlings, which provides some evidence that seedling survival decreases with decreasing plant age. and W. M. He, X. S. Zhang, M. Dong.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2625. Gas exchange, membrane permeability, and ion uptake in two species of Indian jujube differing in salt tolerance
- Creator:
- Gupta, N. K., Meena, S. K., Gupta, S., and Khandelwal, S. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- ion leakage, net photosynthetic rate, salinity, transpiration rate, and Ziziphus
- Language:
- Multiple languages
- Description:
- Effect of NaCl (electrical conductivity of 0, 5, 10, 15, and 20 dS m-1) on growth, gas exchange, and ion uptake in two Ziziphus species (Z. rotundifolia and Z. nummularia) differing in salt tolerance was studied. At 30 and 45 d after first leaf initiation, the dry mass of shoot and leaves, and rates of net photosynthesis (PN) and transpiration (E) decreased significantly with increasing NaCl concentration whereas membrane injury and accumulation of proline increased. The sodium content was highest in the roots of Z. rotundifolia and in the leaves of Z. nummularia. Potassium content did not differ much in the roots but it was significantly higher in the leaves of Z. rotundifolia at 30 and 45 d of observations. Thus both these species were tolerant to salinity but at high salinity Z. rotundifolia performed better owing to its higher PN and E, restricted translocation of sodium from root to leaves, and larger accumulation of potassium in the leaves. and N. K. Gupta ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2626. Gas exchange, photochemical efficiency, and leaf water potential in three Salix species
- Creator:
- Liu, M. Z., Jiang, G. M., Li, Y. G., Gao, L. M., Niu, S. L., Cui, H. X., and Ding, L.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, diurnal courses, leaf water potential, net photosynthetic rate, non-indigenous species, Salix species, stomatal conductance, transpiration rate, and water use efficiency
- Language:
- Multiple languages
- Description:
- Gas exchange, photochemical efficiency, and leaf water potential (Ψl) of Salix matsudana (non-indigenous species), S. microstachya and S. gordejevii (indigenous species) were studied in Hunshandak Sandland, China. Ψl of all the three species decreased from 06:00 to 12:00, and increased afterwards. S. matsudana showed higher values of Ψl than others. Net photosynthetic rate (PN) and stomatal conductance (gs) of S. matsudana were the lowest among all, with the maximum PN at 10:00 being 75% of that of S. gordejevii. Compared with the indigenous species, the non-indigenous S. matsudana had also lower transpiration rate (E) and water use efficiency (WUE). The values of Fv/Fm in all the species were lower from 06:00 to 14:00 than those after 14:00, indicating an obvious depression in photochemical efficiency of photosystem 2 in both non-indigenous and native species. However, it was much more depressed in S. matsudana, the non-indigenous tree. PN was positively correlated to gs and negatively related to Ψl. The relationship between gs and vapour pressure difference (VPD) was exponential, while negative linear correlation was found between gs and Ψl. and M. Z. Liu ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2627. Gas exchanges of an endangered species Syringa pinnatifolia and a widespread congener S. oblata
- Creator:
- Cui, H. X., Jiang, G. M., Niu, S. L., Li, Y. G., Jiang, C. D., Liu, M. Z., and Gao, L. M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- high irradiance, photosynthesis, stomatal conductance, transpiration rate, and water uses efficiency
- Language:
- Multiple languages
- Description:
- Net photosynthetic rate (PN), transpiration rate (E), water use efficiency (WUE), stomatal conductance (gs), and stomatal limitation (Ls) were investigated in two Syringa species. The saturation irradiance (SI) was 400 µmol m-2s-1 for S. pinnatifolia and 1 700 µmol m-2s-1 for S. oblata. Compared with S. oblata, S. pinnatifolia had extremely low gs. Unlike S. oblata, the maximal photosynthetic rate (Pmax) in S. pinnatifoliaoccurred around 08:00 and then fell down, indicating this species was sensitive to higher temperature and high photosynthetic photon flux density. However, such phenomenon was interrupted by the leaf development rhythms before summer. A relatively lower PN together with a lower leaf area and shoot growth showed the capacity for carbon assimilation was poorer in S. pinnatifolia. and H. X. Cui ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2628. Gas exchanges of three co-occurring species of Cypripedium in a scrubland in the Hengduan Mountains
- Creator:
- Zhang, S. B., Hu, H., Xu, K., and Li, Z. R.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- alpine environment, apparent quantum efficiency, carboxylation efficiency, CO2 concentration, concentration, conservation, leaf nitrogen content, respiration rate, and stomatal conductance
- Language:
- Multiple languages
- Description:
- Gas exchanges and related leaf traits of three co-occurring species of genus Cypripedium (C. yunnanense Franch., C. guttatum SW., and C. flavum P.F. Hunt et Summerch.) were investigated in a scrubland at 3 460 m a.s.l. in the Hengduan Mountains. The considered species had similar photosynthetic responses to photosynthetic photon flux density (PPFD) and air temperature. The photosynthetic capacity (Pmax), carboxylation efficiency (CE), apparent quantum efficiency (AQE), PPFD-saturated rate of electron transport (Jmax), respiration rate (RD), and leaf nitrogen content per unit area (LNC) of C. guttatum were higher than those of C. yunnanense and C. flavum. The highest Pmax of C. guttatum was related to the highest LNC and the lowest ratio of intercellular CO2 concentration to atmospheric CO2 concentration (Ci/Ca). However, no significant differences in stomatal conductance (gs) and relative stomatal limitations (RSL) were observed among the three species. Hence biochemical limitation had a dominant role in Pmax differences among the considered species. and S. B. Zhang ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2629. Gas system and method for titration of intact leaves with carbon dioxide
- Creator:
- Oja, V. and Laisk, A.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- boundary layer resistance, buffer capacity of chloroplasts, carbonic anhydrase, CO2 concentration, CO2 evolution, Helianthus annuus L., leaf chamber, pH effect on photosynthesis, pH measurement, and sunflower
- Language:
- Multiple languages
- Description:
- Carbon dioxide, a natural acidic gas, may be ušed for in vivo titration of the buffers in the compartments of cells that contain carbonic anhydíase in intact leaves. A gas systém for the measurement of the CO2 capacity (total inorganic carbon content) of leaves under different extemal CO2 concentrations has been developed. The systém consists of a leaf chamber and of two open (flow-through) channels, one for pre- loading the leaf with CO2 and the other for measurement of the desolubilized CO2. CO2 concentration in the loading channel may be adjusted from 0.03 to 20 %, while CO2 free air is flowing in the burst (desolubilization) channel. The leaf chamber (4.3 X 4.3 X 0.3 cm^) is switched either into the loading channel or into the burst channel. After loading the leaf with high CO2 in the dark the .chamber is switched into the burst channel and the desolubilized CO2 is measured. Preliminary measurements show that the CO2 capacity of a sunflower leaf decreases when the CO2 concentration is increased from 0.03 to 15 %, because of saturation of buffers. The systém can be ušed for direct, non-destructive measurements of pH and buffer capacity in leaf chloroplasts in order to investigate the influence of pH on photosynthesis, the operation of proton pumps and other pH-stabilising mechanisms.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2630. Gas-exchange characteristics, leaf water potential and chlorophyll a fluorescence in oil palm (Elaeis guineensis Jacq.) seedlings under water stress and recovery
- Creator:
- Suresh, K., Nagamani, C., Ramachandrudu, K., and Mathur, R. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, Elaeis guineensis, photosynthesis, photosystem II, stomatal conductance, and transpiration
- Language:
- Multiple languages
- Description:
- The gas-exchange characteristics, leaf water potential and chlorophyll (Chl) a fluorescence of oil palm (Elaeis guineensis Jacq.) seedlings subjected to water stress and recovery were investigated in a greenhouse experiment. At 24 days after imposition of stress, leaf water potential in water-stressed seedlings was doubled compared to that of control and there was a drastic decline in gas-exchange parameters viz. photosynthesis, transpiration, and stomatal conductance. Water stress did not irreversibly affect gas-exchange parameters and quantum efficiency of photosystem II, as seedlings exhibited total recovery of photosynthetic apparatus by 12th day of rehydration. These findings indicate that oil palm exhibits physiological plasticity to water stress during the seedling stage. and K. Suresh ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public