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195. Phenotypes of Alb3p and carotenoid synthesis mutants show similarities regarding light sensitivity, thylakoid structure and protein stability

Creator:
Kugelmann, M., Fausser, A., Ossenbühl, F., and Brennicke, A.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, albino3, Arabidopsis thaliana, carotenoids, hcf106, protein transport, thylakoid membrane, 2, and 58
Language:
Multiple languages
Description:
Chloroplast proteins of the Alb3/YidC/Oxa1p family are necessary for assembly of photosynthetic complexes in the thylakoid membranes. Alb3p in Arabidopsis thaliana is essential for posttranslational LHCII-integration into thylakoid membranes and participates in cotranslational assembly of D1. However, the pleiotropic defects of an Alb3p mutant, albino3, suggest additional functions for Alb3p. To obtain an impression of such potential further Alb3p activities from phenotypic manifestations, properties of mutants disturbed in thylakoid membrane protein transport or carotenoid biosynthesis were compared with the albino3 mutant. Specific defects observed in albino3 were similar to those in a carotenoid synthesis mutant. While this correlation did not provide tangible evidence for Alb3p being involved in the integration of carotenoids in photosynthetic complexes, it suggests a possible avenue for future investigations., M. Kugelmann, A. Fausser, F. Ossenbühl, A. Brennicke, and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

196. Photosynthesis and activity of photosystem II in response to drought stress in Amur Grape (Vitis amurensis Rupr.)

Creator:
Wang, Z. X., Chen, L., Ai, J., Qin , H. Y., Liu, Y. X., Xu, P. L., Jiao, Z. Q., Zhao, Y., and Zhang, Q. T.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, Amur Grape, drought stress, JIP-test, net photosynthetic rate, photosystem II, 2, and 58
Language:
Multiple languages
Description:
The Amur Grape (Vitis amurensis Rupr.) cultivars ’shuangFeng’ and ‘ZuoShanyi’ were grown in shelter greenhouse under natural sunlight and subjected to drought. Sap flow rate, net photosynthetic rate (PN), and chlorophyll (Chl) fluorescence were measured on Amur Grape leaves subjected to different drought treatments. Significant decreases in P N were associated with increasing intercellular CO2 concentration (Ci), suggesting that the reduction in PN was caused by nonstomatal limitation. Analysis of OJIP transients according to the JIP-test protocol revealed that specific (per PSII reaction center) energy fluxes for light absorption, excitation energy trapping and electron transport have significantly changed. The appearance of a pronounced K-step and J-step in polyphasic rise of fluorescence transient suggested the oxygen-evolving complex and electron transport were inhibited. Drought stress has relatively little effect on the parameter maximal quantum yield of PSII photochemistry (Fv/Fm), but the performance index (PIABS) is more sensitive in different drought treatment. There are cultivar differences in the response of PSII activity to drought, the photosynthetic apparatus of ‘ZuoShanyi’ cultivar is more resistant to drought than that of ‘ShuangFeng’, and JIP-test could be a useful indicator for evaluation and selection to drought tolerance., Z. X. Wang ... [et al.]., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

197. Photosynthesis and nitrogen allocation in needles in the sun and shade crowns of hybrid larch saplings: effect of nitrogen application

Creator:
Mao, Q. Z., Watanabe, M., Imori, M., Kim, Y. S., Kita, K., and Koike, T.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, foliar nutrient, hybrid larch, nitrogen deposition, sun- and shade needles, 2, and 58
Language:
Multiple languages
Description:
We studied the effects of applying 50 kg(N) ha-1 year-1 of nitrogen (N) on needle photosynthesis, N allocation and nutrient content in the sun- and shade crowns of the hybrid larch F1 (Larix gmelinii var. japonica × L. kaempferi). The light-saturated net photosynthetic rate (PNmax) was not significantly affected by N application or crown position, although the contents of N, P, K, and chlorophyll (Chl), and the maximum rates of carboxylation and electron transport were lower in needles of the shade crown than of the sun crown. This difference was mainly due to an increase in the intercellular CO2 concentration (Ci) in the needles of the shade crown. Analysis of N allocation in photosynthetic systems revealed that more N was allocated to functions related to electron transport and ribulose-1,5-bisphosphate (RuBP) regeneration in needles of the shade crown. N allocation in needles of the hybrid larch F1 was regulated mainly by the light conditions, rather than by N application., Q. Z. Mao ... [et al.]., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

198. Photosynthesis and root characteristics of rice (Oryza sativa L.) in floating culture

Creator:
Wu, H.-X., Ma, Y.-Z., Xiao, J.-P., Zhang, Z.-H., and Shi, Z.-H.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, eutrophic lake, photosynthetic characteristics, productivity, root characteristics, tillage, 2, and 58
Language:
Multiple languages
Description:
To address the issue of water eutrophication and to use water more effectively, we conducted experiments on rice (Oryza sativa L.) grown in floating culture. From 2009 to 2011, we compared the photosynthesis and root characteristics of the rice, hybrid line Zhuliangyou 02, grown under a conventional tillage and in a floating culture in Huaihua, the home of hybrid rice. Rice in the floating culture showed a higher net photosynthetic rate and stomatal conductance than that under the conventional tillage. The activities of phosphoenolpyruvate carboxylase and NADP-malic enzyme were 32 and 28% higher, respectively, in rice in the floating culture than under the conventional tillage. Rice in the floating culture also showed significantly greater number of roots, root activity, and antioxidant enzyme activity than that under the conventional tillage. Compared with rice under the conventional tillage, rice in the floating culture had 18 and 24% higher tiller number and effective panicle number, respectively. These results suggested that the floating culture system can promote rice production through enhancing root absorption, increasing effective panicle number, and improving the photosynthetic rate. In addition, rice cultivated in the floating culture could remove excess nutrients from water, which addresses the problems of a lack of arable land and water pollution., H.-X. Wu ... [et al.]., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

199. Photosynthesis under stressful environments: an overview

Creator:
Ashraf, M. and Harris, P. J. C.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, drought, fluorescence, gas exchange, heat, photosynthesis, photosynthetic pigments, salinity, salinity stress, 2, and 58
Language:
Multiple languages
Description:
Stressful environments such as salinity, drought, and high temperature (heat) cause alterations in a wide range of physiological, biochemical, and molecular processes in plants. Photosynthesis, the most fundamental and intricate physiological process in all green plants, is also severely affected in all its phases by such stresses. Since the mechanism of photosynthesis involves various components, including photosynthetic pigments and photosystems, the electron transport system, and CO2 reduction pathways, any damage at any level caused by a stress may reduce the overall photosynthetic capacity of a green plant. Details of the stress-induced damage and adverse effects on different types of pigments, photosystems, components of electron transport system, alterations in the activities of enzymes involved in the mechanism of photosynthesis, and changes in various gas exchange characteristics, particularly of agricultural plants, are considered in this review. In addition, we discussed also progress made during the last two decades in producing transgenic lines of different C3 crops with enhanced photosynthetic performance, which was reached by either the overexpression of C3 enzymes or transcription factors or the incorporation of genes encoding C4 enzymes into C3 plants. We also discussed critically a current, worldwide effort to identify signaling components, such as transcription factors and protein kinases, particularly mitogen-activated protein kinases (MAPKs) involved in stress adaptation in agricultural plants., M. Ashraf, P. J. C. Harris., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

200. Photosynthesis, energy partitioning, and metabolic adjustments of the endangered Cistaceae species Tuberaria major under high temperature and drought

Creator:
Osório, M. L., Osório, J., and Romano, A.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, anthocyanins, chlorophyll fluorescence imaging, energy partitioning, malondialdehyde, proline, soluble sugars, 2, and 58
Language:
Multiple languages
Description:
In view of predicted climatic changes for the Mediterranean region, study of high temperature and drought impacts on physiological responses of endangered species regains relevance. In this context, micropropagated plants of Tuberaria major, a critically endangered species, endemic of Algarve, were transferred to a controlled-environment cabinet with day/night temperatures set at 25/18°C (Reference) or 32/21°C (HT). After 15 days of HT acclimation, some plants were subjected to progressive drought followed by rewatering. The enhancement of temperature alone did not affect water relations and photosynthetic rates (PN) but the stomatal conductance (gs) exhibited a 3-fold increase in comparison with reference plants. The maximum quantum yield of photosystem (PS) II (Fv/Fm), the effective quantum yield of PSII photochemistry (ΦPSII), carotenoid (Car) and anthocyanin content enhanced, whereas the quantum yields of regulated (ΦNPQ) and nonregulated (ΦNO) energy dissipation decreased. Drought combined with HT reduced predawn leaf water potential to values of about -1.3 MPa, which had adverse effects on gas exchange and PSII activity. Values of PN and gs were 71 and 79% lower than those of HT plants. An impairment of photochemical activity was also observed: the decrease in ΦPSII and the increase of ΦNPQ. However, an irreversible photoinhibitory damage had not occurred. Carotenoid and anthocyanin content remained elevated and soluble sugars (SS) increased twice, whereas proline and MDA accumulation was not detected. On the first 24 h after water-stress relief, gs, PN, ΦPSII, and ΦNPQ did not recover, but SS returned to the reference level. Overall, T. major acquired an adequate capacity for a protection against the development of oxidative stress during drought and water recovery under HT. These findings suggest that T. major is prepared to deal with predicted climate changes., M. L. Osório, J. Osório, A. Romano., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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