Physiological and biochemical responses of Sorghum vulgare plants to supplemental ultraviolet-B radiation

1998 ◽  
Vol 76 (7) ◽  
pp. 1290-1294 ◽  
Author(s):  
Navin Kumar Ambasht ◽  
Madhoolika Agrawal
Keyword(s):  
Ascorbic Acid ◽  
Gas Exchange ◽  
Peroxidase Activity ◽  
Plant Biomass ◽  
Stratospheric Ozone ◽  
Ascorbic Acid Content ◽  
Ultraviolet B ◽  
Sorghum Vulgare ◽  
Ultraviolet B Radiation ◽  
Physiological And Biochemical

Sorghum (Sorghum vulgare (Pers.) cv. MSH 51) plants were grown in the field under ambient and supplemental levels of ultraviolet-B radiation (UV-B; supplemental daily dose corresponding to a 20% reduction in the stratospheric ozone column). Gas exchange characteristics, biomass, and levels of photosynthetic pigments, flavonoids, catalase, peroxidase activity, and ascorbic acid were determined to evaluate the changes induced by enhanced levels of UV-B irradiation. Gas exchange analysis indicated that one of the reasons for the decline in photosynthesis is stomatal limitation. Enhanced UV-B also caused reductions in chlorophyll and carotenoid pigments after 60 days of exposure. Concentrations of UV-B absorbing pigments increased linearly with age. UV-B irradiation also increased phenolic compounds. Catalase activity decreased, while peroxidase activity increased in response to elevated UV-B. There was a decrease in total plant biomass and ascorbic acid content of plants exposed to UV-B. Thus, an enhanced level of UV-B irradiation over a long period has a cumulative unfavourable effect on a number of physiological and biochemical processes, leading to a reduction in dry matter production.Key words: UV-B radiation, Sorghum vulgare, photosynthesis, stomatal resistance, flavonoids, peroxidase.

Changes in ascorbic acid content and ascorbate peroxidase activity during the development of Acetabularia mediterranea

1986 ◽  
Vol 33 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Federico J. Castillo ◽  
Geneviève Cotton ◽  
Claire Kevers ◽  
Hubert Greppin ◽  
Thomas Caspar ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Ascorbate Peroxidase ◽  
Peroxidase Activity ◽  
Acid Content ◽  
Ascorbic Acid Content ◽  
Acetabularia Mediterranea

Influence of ultraviolet-B radiation, stratospheric ozone variability, and thermal stratification on the phytoplankton biomass dynamics in a mesohumic lake

2000 ◽  
Vol 57 (3) ◽  
pp. 600-609 ◽  
Author(s):  
Marguerite A Xenopoulos ◽  
Yves T Prairie ◽  
David F Bird
Keyword(s):  
Phytoplankton Biomass ◽  
Thermal Stratification ◽  
Stratospheric Ozone ◽  
Negative Relationship ◽  
Taxonomic Composition ◽  
Ultraviolet B ◽  
Temporary Increase ◽  
Ultraviolet B Radiation ◽  
Major Shift ◽  
The Impact

Terrestrial ultraviolet radiation (UVR) is highly variable in both space and time, and phytoplankton in the mixed layer may be exposed at irregular intervals to significant daily doses. The influence of the natural UVR on phytoplankton dynamics was investigated in a small mesohumic lake, Lac Cromwell, in the Laurentian Hills by means of a time-intensive (about 60 days) daily study of the relationship between UVR flux and phytoplankton biomass. Following the onset of lake stratification, at which time the epilimnion became shallower than 2.5 m, the study revealed a strong negative relationship between ultraviolet-B radiation (UVB) and algal biomass at the surface (r 2 = 0.61) and at 1 m (r 2 = 0.38). Although this relationship held throughout the stratified period, chlorophyll a concentration declined particularly rapidly (-65%) during a short-lived ozone-thinning period. There was a major shift in the community taxonomic composition during the same period from a typical diatom-chrysophyte spring bloom towards a dinoflagellate-dominated community that was followed by cyanobacteria. Here, we present evidence that the impact of the temporary increase in UVB was intensified by a concurrent lack of mixing, indicating that turbulence and thermal stratification are key components modulating UVB effects in lakes.

Changes in ascorbic acid content and ascorbate peroxidase activity during the development of Acetabularia mediterranea

1987 ◽  
Vol 33 (3) ◽  
pp. 17-23
Author(s):  
Federico J. Castillo ◽  
Geneviève Cotton ◽  
Claire Kevers ◽  
Hubert Greppin ◽  
Thomas Gaspar ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Ascorbate Peroxidase ◽  
Peroxidase Activity ◽  
Acid Content ◽  
Ascorbic Acid Content ◽  
Acetabularia Mediterranea

scholarly journals Possible Effects of Greenhouse Gases to Ozone Profiles and DNA Active UV-B Irradiance at Ground Level

Atmosphere ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 228 ◽  
Author(s):  
Kostas Eleftheratos ◽  
John Kapsomenakis ◽  
Christos S. Zerefos ◽  
Alkiviadis F. Bais ◽  
Ilias Fountoulakis ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Total Ozone ◽  
Climate Models ◽  
Stratospheric Ozone ◽  
Ground Level ◽  
Chemical Processes ◽  
Ultraviolet B ◽  
Model Calculations ◽  
Ultraviolet B Radiation ◽  
Solar Ultraviolet

In this paper, we compare model calculations of ozone profiles and their variability for the period 1998 to 2016 with satellite and lidar profiles at five ground-based stations. Under the investigation is the temporal impact of the stratospheric halogen reduction (chemical processes) and increase in greenhouse gases (i.e., global warming) on stratospheric ozone changes. Attention is given to the effect of greenhouse gases on ultraviolet-B radiation at ground level. Our chemistry transport and chemistry climate models (Oslo CTM3 and EMAC CCM) indicate that (a) the effect of halogen reduction is maximized in ozone recovery at 1–7 hPa and observed at all lidar stations; and (b) significant impact of greenhouse gases on stratospheric ozone recovery is predicted after the year 2050. Our study indicates that solar ultraviolet-B irradiance that produces DNA damage would increase after the year 2050 by +1.3% per decade. Such change in the model is driven by a significant decrease in cloud cover due to the evolution of greenhouse gases in the future and an insignificant trend in total ozone. If our estimates prove to be true, then it is likely that the process of climate change will overwhelm the effect of ozone recovery on UV-B irradiance in midlatitudes.

Sign in / Sign up

Export Citation Format

Share Document