scholarly journals Environmental effects on photosynthetic capacity of bean genotypes

2004 ◽  
Vol 39 (7) ◽  
pp. 615-623 ◽  
Author(s):  
Rafael Vasconcelos Ribeiro ◽  
Mauro Guida dos Santos ◽  
Gustavo Maia Souza ◽  
Eduardo Caruso Machado ◽  
Ricardo Ferraz de Oliveira ◽  
...  
Keyword(s):  
High Temperature ◽  
Natural Condition ◽  
Temperature Effects ◽  
Environmental Changes ◽  
Photosynthetic Capacity ◽  
Photosynthetic Apparatus ◽  
Co2 Assimilation ◽  
Fluorescence Yield ◽  
Environmental Condition ◽  
Response Curves

Photosynthetic responses to daily environmental changes were studied in bean (Phaseolus vulgaris L.) genotypes 'Carioca', 'Ouro Negro', and Guarumbé. Light response curves of CO2 assimilation and stomatal conductance (g s) were also evaluated under controlled (optimum) environmental condition. Under this condition, CO2 assimilation of 'Carioca' was not saturated at 2,000 µmol m-2 s-1, whereas Guarumbé and 'Ouro Negro' exhibited different levels of light saturation. All genotypes showed dynamic photoinhibition and reversible increase in the minimum chlorophyll fluorescence yield under natural condition, as well as lower photosynthetic capacity when compared with optimum environmental condition. Since differences in g s were not observed between natural and controlled conditions for Guarumbé and 'Ouro Negro', the lower photosynthetic capacity of these genotypes under natural condition seems to be caused by high temperature effects on biochemical reactions, as suggested by increased alternative electron sinks. The highest g s values of 'Carioca' were observed at controlled condition, providing evidences that reduction of photosynthetic capacity at natural condition was due to low g s in addition to the high temperature effects on the photosynthetic apparatus. 'Carioca' exhibited the highest photosynthetic rates under optimum environmental condition, and was more affected by daily changes of air temperature and leaf-to-air vapor pressure difference.

scholarly journals Influence of High Temperature on Photosynthesis, Antioxidative Capacity of Chloroplast, and Carbon Assimilation among Heat-tolerant and Heat-susceptible Genotypes of Nonheading Chinese Cabbage

HortScience ◽  
2017 ◽  
Vol 52 (11) ◽  
pp. 1464-1470 ◽  
Author(s):  
Lingyun Yuan ◽  
Yujie Yuan ◽  
Shan Liu ◽  
Jie Wang ◽  
Shidong Zhu ◽  
...  
Keyword(s):  
High Temperature ◽  
Chinese Cabbage ◽  
Photosynthetic Capacity ◽  
Photochemical Efficiency ◽  
Membrane Integrity ◽  
Photosynthetic Apparatus ◽  
Carbon Assimilation ◽  
Light Reaction ◽  
Chlorophyll Contents ◽  
Heat Tolerant

High temperature (HT) is a major environmental stress limiting oversummer production of nonheading Chinese cabbage (NHCC, Brassica campestris ssp. chinensis Makino). In the present study, the effects of HT on photosynthetic capacity, including light reaction and carbon assimilation, were completely investigated in two NHCC, ‘xd’ (heat-tolerant), and ‘sym’ (heat-susceptible). The two genotypes showed significant differences in plant morphology, photosynthetic capacity, and photosynthate metabolism (carboassimilation). HT caused a decrease in photosynthesis, chlorophyll contents, and photochemical activity in NHCC. However, these main photosynthetic-related parameters, including net photosynthetic rate (PN), maximal photochemical efficiency of PSII (Fv/Fm), and total chlorophyll content in ‘xd’, were significantly higher than those of ‘sym’ plants. The antioxidant contents and antioxidative enzyme activities of ascorbic acid-reduced glutathione cycle in the chloroplast of ‘xd’ were significantly higher than those of ‘sym’. Microscopic analyses revealed that HT affected the structure of photosynthetic apparatus and membrane integrity to a different extent, whereas ‘xd’ could maintain a better integrated chloroplast shape and thylakoid. Inhibited light reaction also hampered carbon assimilation, resulting in a decline of carboxylation efficiency and imbalance of carbohydrate metabolism. However, larger declined extents in these data were presented in ‘sym’ (heat-susceptible) than ‘xd’ (heat-tolerant). The heat-tolerant genotype ‘xd’ had a better capacity for self-protection by improved light reaction and carbon assimilation responding to HT stress.

scholarly journals High temperature effects on the response of photosynthesis to light in sweet orange plants infected with Xylella fastidiosa

2003 ◽  
Vol 15 (2) ◽  
pp. 89-97 ◽  
Author(s):  
Rafael Vasconcelos Ribeiro ◽  
Eduardo Caruso Machado ◽  
Ricardo Ferraz de Oliveira ◽  
Carlos Pimentel
Keyword(s):  
High Temperature ◽  
Photosystem Ii ◽  
Oxygen Evolution ◽  
Quantum Efficiency ◽  
Temperature Effects ◽  
Sweet Orange ◽  
Xylella Fastidiosa ◽  
Fluorescence Yield ◽  
Photosynthetic Oxygen Evolution ◽  
Photosynthetic Oxygen

The objective of this study was to evaluate the high temperature effects on the response of photosynthesis to light in sweet orange plants infected with Xylella fastidiosa. This vascular bacterium is the causal agent of the citrus variegated chlorosis that causes severe economical losses to the Brazilian citrus industry. The responses of the photosynthetic oxygen evolution and the parameters related to chlorophyll a fluorescence to the increase in light intensity were evaluated at 35ºC and 45ºC in both healthy and infected leaf discs. The increase in temperature affected the photosynthetic apparatus of both healthy and infected plants, although infected plants showed higher photochemical sensitivity at the higher temperature (e.g. in the potential quantum efficiency of photosystem II, maximum and basal fluorescence yield, and in the relation between variable and basal fluorescence yield). This higher sensitivity of infected plants was not reflected in the overall photosynthetic reaction, since photosynthetic oxygen evolution values did not vary at 45ºC. Healthy and infected plants showed differences in photosynthetic oxygen evolution but displayed similar effective quantum efficiency of photosystem II as well as apparent electron transport rates at 35ºC. These results suggest that the limitations in photosynthesis observed on the infected plants might arise through impaired biochemical reactions.

scholarly journals Economic and Environmental Changes in Shenzhen—A Technology Hub in Southern China

2021 ◽  
Vol 13 (10) ◽  
pp. 5545
Author(s):  
Wai-Ming To ◽  
Peter K. C. Lee ◽  
Antonio K. W. Lau
Keyword(s):  
Environmental Kuznets Curve ◽  
Environmental Changes ◽  
Value Added ◽  
Clean Energy ◽  
Manufacturing Industries ◽  
Kuznets Curve ◽  
Environmental Condition ◽  
Computer Communication ◽  
Electronic Product ◽  
Product Manufacturing

Shenzhen has been established as the technology and innovation center in China. The study reviews its economic development and environmental change over the past four decades. Specifically, it tests whether environmental Kuznets curve relationship between haze as a proxy indicator of environmental condition and gross domestic product (GDP) per capita holds in Shenzhen. The study also examines the contribution of Shenzhen’s secondary sector to its GDP and highlights some changes in the computer, communication and electronic product manufacturing industries over the years. We collected the official data from the Shenzhen Municipal Government. Economic, social and environmental changes in Shenzhen were identified using tables and stacked graphs. Environmental Kuznets curve revealed that the worst environmental condition appeared in Shenzhen during the period 2003–2004. Environmental analysis showed that Shenzhen’s computer, communication and electronic product manufacturing industries consumed 52,595 TJ of energy and produced 10.1 million tons CO2-eq in 2019. As gross output value of the industries was USD 336 billion in 2019, the industries had an energy efficiency of 156,716 MJ/million USD and an emission efficiency of 30.6 tons CO2-eq/million USD, improving by 74% and 65%, respectively, since 2008. Nevertheless, the industries should focus more on high value-added and low energy-intensive technologies and innovations. Additionally, the Shenzhen Government shall increase the use of clean energy sources such as nuclear, wind and solar power in order to sustain the continual improvement of energy and emission efficiencies for all industries.

High Temperature Effects in Li-Doped ZnO Thin Films

2004 ◽  
Vol 63 (1) ◽  
pp. 209-213 ◽  
Author(s):  
A. DEYNEKA ◽  
Z. HUBICKA ◽  
M. CADA ◽  
G. SUCHANECK ◽  
M. SAVINOV ◽  
...  
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Temperature Effects ◽  
Zno Thin Films ◽  
Doped Zno

Photosynthetic Capacity, Antioxidant Activity and Molecular Responses in Parthenocissus Quinquefolia (L.) Planch Under High Temperature Stress and Subsequent Recovery

2021 ◽  
Vol 50 (2) ◽  
pp. 433-436
Author(s):  
Yuan Xue Tao ◽  
Li Fu Ping
Keyword(s):  
High Temperature ◽  
Antioxidant Enzyme ◽  
Temperature Stress ◽  
Photosynthetic Capacity ◽  
D1 Protein ◽  
Temperature Limit ◽  
High Temperature Stress ◽  
Psii Activity ◽  
Increasing Temperature ◽  
Parthenocissus Quinquefolia

Photosynthetic capacity and photosystem II (PSII) activity decreased with increasing temperature, whereas antioxidant enzyme activity showed the opposite trend. High temperature stress induced a significant increase in Φf,D, and D1 protein turnover rate. Photosynthetic capacity, PSII activity, and antioxidant enzyme levels in plants treated at 35 and 40°C were restored to control levels upon stress relief, whereas those in plants grown at 45℃ were only partially restored. Therefore, the temperature limit for heat tolerance in Parthenocissus quinquefolia is between 40 and 45℃. Further, it was observed that antioxidant enzymes were crucial for high-temperature stress resistance in P. quinquefolia, with DEGP1 protein playing a major role in the rapid turnover of D1 protein for PSII repair. Bangladesh J. Bot. 50(2): 433-436, 2021 (June)

Could black anti-hail net have an extra role as an amelioration agent against heat stress in kiwifruit?

2021 ◽  
pp. 1-17
Author(s):  
Peter A. Roussos ◽  
Athanassios Tsafouros ◽  
Efstathios Ntanos ◽  
Nikoleta-Kleio Denaxa ◽  
Anna Kosta ◽  
...  
Keyword(s):  
High Temperature ◽  
Organic Acids ◽  
Antioxidant Capacity ◽  
Fruit Quality ◽  
Photosynthetic Capacity ◽  
Titratable Acidity ◽  
Soluble Solids ◽  
Hail Net ◽  
Future Production ◽  
Present Trial

BACKGROUND: Kiwifruit plants are extremely sensitive to hail storms. Black anti-hail nets are the most frequently used in kiwifruit culture, to protect both the plant and current as well as future production. OBJECTIVE: The present trial aimed to assess if the black hail net could also serve as an amelioration agent against high temperature and irradiance during the summer months. METHODS: The photosynthetic capacity, the yield, and fruit quality (carbohydrates, organic acids, phenolic compounds, and antioxidant capacity) of “Hayward” kiwifruit cultivar, both at harvest and after three months of storage were evaluated. RESULTS: Photosynthetic capacity under the net was slightly higher compared to control, while leaf temperature was always lower during the summer and autumn. The yield was significantly enhanced under the net, while the fruits exhibited higher titratable acidity, organic acids, and ascorbic acid concentration. After the storage, fruits produced from vines grown under net still had higher organic acid content, as well as total soluble solids but lower antioxidant capacity compared to control. CONCLUSIONS: Net installation above kiwifruit canopy seems to alleviate the effects of high temperature and heat load on kiwifruit vines, under saturating light intensity, inducing higher yields with good fruit quality.

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