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2. 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
3. Increase in resistance to low temperature photoinhibition following ascorbate feeding is attributable to an enhanced xanthophyll cycle activity in rice (Oryza sativa L.) leaves
- Creator:
- Xu, C.-C., Lin, R.-C., Li, L.-B., and Kuang, T.-Y.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- antheraxanthin, chilling, chlorophyll fluorescence, high irradiance, photochemical quenching, thermal energy dissipation, violaxanthin, and zeaxanthin
- Language:
- Multiple languages
- Description:
- The mechanistic basis for protection of exogenous ascorbate against photoinhibition at low temperature was examined in leaves of rice (Oryza sativa L.). Exposure of intact leaves to chilling temperature resulted in a drastic decrease in the speed of development of non-photochemical fluorescence quenching (NPQ). This was related to the low temperature-imposed restriction on the formation of the fast relaxing component of NPQ (qf). Feeding with 20 mM ascorbate markedly increased the rate of qf development at chilling temperature due primarily to the enhanced rate of zeaxanthin (Z) formation. On the other hand, ascorbate feeding had no influence on photosystem 2 (PS2)-driven electron flow. The reduced state of the PS2 primary electron acceptor QA decreased in ascorbate-fed leaves exposed to high irradiance at chilling temperature owing to the increased Z-associated thermal energy dissipation in the light-harvesting antenna system of PS2. Furthermore, ascorbate feeding increased the photosynthetic apparatus of rice leaves to resist photoinhibition at low temperature. The protective effect of exogenous ascorbate was fully accounted for by the enhanced xanthophyll cycle activity. and C.-C. Xu ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4. Responses of ribulose-1,5-bisphosphate carboxylase, protein content, and stomatal conductance to water deficit in maize, tomato, and bean
- Creator:
- Castrillo, M., Fernandez, D., A. M., Trujillo, I., and Guenni, L.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Lycopersicum esculentum, Phaseolus vulgaris, protein, water potential, and Zea mays
- Language:
- Multiple languages
- Description:
- We compared responses of maize, tomato, and bean plants to water stress. Maize reached a severe water deficit (leaf water potential -1.90 MPa) in a longer period of time as compared with tomato and bean plants. Maize stomatal conductance (gs) decreased at mild water deficit. gs of tomato and bean decreased gradually and did not reach values as low as in maize. The protein content was maintained in maize and decreased at low water potential (ψw); in tomato it fluctuated and also decreased at low ψw; in bean it gradually decreased. Ribulose-1,5-bisphosphate carboxylase/oxygenase activity remained high at mild and moderate stress in maize and tomato plants; in bean it remained high only at mild stress. and M. Castrillo ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public