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2. Effects of drought stress on growth and chlorophyll fluorescence of Lycium ruthenicum Murr. seedlings
- Creator:
- Guo, Y.-Y., Yu, H.-Y., Kong, D.-S., Yan, F., and Zhang, Y.-J.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, chlorofyl, photosynthesis, chlorophyll, tolerance sucha, relativní obsah vody, bazální průměr, koruna, list, kustovnice ruténská, drought tolerance, dry mass, relative water content, basal diameter, crown, chlorophyll fluorescence, leaf, nonphotochemical quenching, nonphotochemical quenching coefficient, 2, and 581
- Language:
- Multiple languages
- Description:
- The present study aimed to determine effects of drought stress on Lycium ruthenicum Murr. seedlings. Our results showed that mild drought stress was beneficial to growth of L. ruthenicum seedlings. Their height, basal diameter, crown, leaf number, stem dry mass, leaf and root dry mass increased gradually when the soil water content declined from 34.7 to 21.2%. However, with further decrease of the soil water content, the growth of L. ruthenicum seedlings was limited. After 28 d of treatment, the seedlings were apparently vulnerable to drought stress, which resulted in significant leaf shedding and slow growth. However, growth was restored after rehydration. Drought treatments led to a decrease in contents of chlorophyll (Chl) a, b, and Chl (a+b) and increase in the Chl a/b ratio. After rewatering, the Chl content recovered to the content of the control plants. Under drought stress, minimal fluorescence and nonphotochemical quenching coefficient increased, thereby indicating that L. ruthenicum seedlings could protect PSII reaction centres from damage. Maximum fluorescence, maximum quantum yield, actual quantum yield of PSII photochemistry, and photochemical quenching decreased, which suggested that drought stress impacted the openness of PSII reaction centres. A comparison of these responses might help identify the drought tolerance mechanisms of L. ruthenicum. This could be the reference for the planting location and irrigation arrangements during the growing period of L. ruthenicum., Y.-Y. Guo, H.-Y. Yu, D.-S. Kong, F. Yan, Y.-J. Zhang., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3. Effects of water deficit on photosynthetic rate and osmotic adjustment in tetraploid wheats
- Creator:
- Rekika, D., Nachit, M. M., Araus, J. L., and Monneveux, P.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- drought tolerance, durum wheat, intercellular CO2 concentration, leaf water status, Triticum, water stress, and wild emmer wheat
- Language:
- Multiple languages
- Description:
- Osmotic adjustment, accumulation of soluble saccharides, and photosynthetic gas exchange were studied in five durum wheat (Triticum turgidum L. var. durum) and one wild emmer wheat (Triticum turgidum L. var. dicoccoïdes) cultivars of contrasting drought tolerance and yield stability. Soil water contents (SWC) were 100, 31, 20, and 12 % of maximum capillary capacity. Under mild water stress (SWC 31 to 20 %), osmotic adjustment capacity and high accumulation of saccharides were found in cv. Cham1, a high yielding and drought tolerant cultivar, and in var. dicoccoïdes, while lowest values were noted in the durum wheat landraces Oued-Zenati and Jennah-Khotifa. Under more severe water stress (SWC 12 %), the cv. Cham1 maintained higher net photosynthetic rate (PN) than other genotypes. The observed changes in the ratio intercellular/ambient CO2 concentration (ci/ca) indicated that under mild and severe water stress, the decrease in PN was mainly due to stomatal and non-stomatal factors, respectively. and D. Rekika ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4. Impact of arbuscular mycorrhizal fungi on the growth, water status, and photosynthesis of hybrid poplar under drought stress and recovery
- Creator:
- Liu, T., Sheng, M., Wang, C. Y., Chen, H., Li, Z., and Tang, M.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, topol, photosynthesis, poplar, Shaanxi (Čína : provincie), Shaanxi (China : Province), drought tolerance, gas exchange, nonphotochemical quenching, photosynthetic capacity, relative water content, Rhizophagus irregularis, 2, and 581
- Language:
- Multiple languages
- Description:
- Poplars (Populus spp.) are widely used in the pulp and paper industry and as bioenergy resources. Poplars require a large amount of water for biomass accumulation and lack of water is a limiting factor for poplar growth. Arbuscular mycorrhizal (AM) fungi have been previously reported to afford some plant species with greater resistance to drought stress. However, the effects of AM fungi on hybrid poplar under drought stress and recovery have not been studied. The main aim of this study was to evaluate the effects of the AM fungus, Rhizophagus irregularis, on the growth, water status, chlorophyll (Chl) content and fluorescence, and photosynthesis of poplar seedlings. The experiment was divided into three stages. At each stage of the experiment, the seedlings were subjected to a different watering regime: well-watered (prior stress), drought, and then rewatering (recovery). Measurements were taken at the end of each stage of the experiment. The results showed that mycorrhizal plants had a higher net photosynthetic rate and Chl fluorescence compared with nonmycorrhizal plants, regardless of the stage. Mycorrhizal and nonmycorrhizal plants showed different responses to drought stress: mycorrhizal plants showed better water-use efficiency and water uptake under drought stress conditions. In general, the poplar seedlings that formed the AM symbiosis with R. irregularis showed enhanced growth and reduced loss of biomass during the drought stress compared with the nonmycorrhizal seedlings., T. Liu, M. Sheng, C. Y. Wang, H. Chen, Z. Li, M. Tang., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5. Sequence of physiological responses in groundnut (Arachis hypogaea L.) subjected to soil moisture deficit
- Creator:
- Jeyaramraja, P. R. and Thushara, S. S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, drought susceptibility, drought tolerance, net photosynthesis, peanut, physiological mechanism, water-use efficiency, 2, and 581
- Language:
- Multiple languages
- Description:
- Responses of drought-tolerant (DT) and drought-susceptible (DS) pot-grown groundnut (Arachis hypogaea L.) varieties to changes in leaf relative water content (RWC) were studied. Water stress (WS) was imposed on 30-day-old plants for 2 weeks. Leaf RWC decreased significantly under WS conditions with simultaneous decrease in net photosynthetic rate (PN) and stomatal conductance (gs). Even though no significant difference was observed between DT and DS varieties with regard to RWC, DT varieties were able to maintain significantly higher PN than DS varieties. Higher values of water use efficiency (WUE) were also observed in DT varieties during WS conditions. The decline in PN due to WS could be attributed to both reduction in g s (i.e. stomatal limitation) and to reduction in chlorophyll content (Chl). No significant difference in leaf area index (LAI) was found between DT and DS types and LAI was not reduced by WS. Significant differences were found among the studied groundnut varieties, but not between DT and DS types, in terms of root, aboveground, and total dry mass. These growth parameters significantly decreased under WS conditions. Based on the results, a sequence of physiological responses in groundnut crop subjected to WS was postulated. and P. R. Jeyaramraja, S. S. Thushara.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public