Abstract
It is believed that increased levels of ultraviolet B-radiation (UV-B;280-320 nm) will result in serious threat to plant. In the present study the effects of UV (particularly UV-B) were studied on chlorophyll fluorescence, ultraweak luminescence (UL) and plant growth. Parameters related to light emission were determined, and the effects of UV-B on hypocotyl elongation and levels of free IAA were examined. The plants were grown in greenhouse or in growth chambers and exposed to short or long term UV-B simulating different levels of ozone depletion. Short exposure of Hibiscus leaves to UV resulted in a gradual increase in both UL and peroxidase activity followed by a decline after 72 h and a decrease in variable chlorophyll fluorescence. The action of UV-B on sugar beet plants depended on light quality and irradiance and infection by Cercospora beticola Sacc. The interaction between UV-B and the disease resulted in a large reduction of dry weight and enhanced UL. The lowest Chl a and growth was found in plants grown under low irradiance and exposed to UV-B supplemented with UV-A (320-400 nm). UVB also inhibited photosystem II, increased UL and peroxidase activity. Under relatively high PAR, UV-B increased dry weight of laminae and UL
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Citation Formats
Panagopoulos, I.
Effects of ultraviolet radiation on Hibiscus rosa-sinensis, Beta vulgaris and Helianthus annuus.
Sweden: N. p.,
1992.
Web.
Panagopoulos, I.
Effects of ultraviolet radiation on Hibiscus rosa-sinensis, Beta vulgaris and Helianthus annuus.
Sweden.
Panagopoulos, I.
1992.
"Effects of ultraviolet radiation on Hibiscus rosa-sinensis, Beta vulgaris and Helianthus annuus."
Sweden.
@misc{etde_10127737,
title = {Effects of ultraviolet radiation on Hibiscus rosa-sinensis, Beta vulgaris and Helianthus annuus}
author = {Panagopoulos, I}
abstractNote = {It is believed that increased levels of ultraviolet B-radiation (UV-B;280-320 nm) will result in serious threat to plant. In the present study the effects of UV (particularly UV-B) were studied on chlorophyll fluorescence, ultraweak luminescence (UL) and plant growth. Parameters related to light emission were determined, and the effects of UV-B on hypocotyl elongation and levels of free IAA were examined. The plants were grown in greenhouse or in growth chambers and exposed to short or long term UV-B simulating different levels of ozone depletion. Short exposure of Hibiscus leaves to UV resulted in a gradual increase in both UL and peroxidase activity followed by a decline after 72 h and a decrease in variable chlorophyll fluorescence. The action of UV-B on sugar beet plants depended on light quality and irradiance and infection by Cercospora beticola Sacc. The interaction between UV-B and the disease resulted in a large reduction of dry weight and enhanced UL. The lowest Chl a and growth was found in plants grown under low irradiance and exposed to UV-B supplemented with UV-A (320-400 nm). UVB also inhibited photosystem II, increased UL and peroxidase activity. Under relatively high PAR, UV-B increased dry weight of laminae and UL but no effect on Chl content. Sugar beet plants grown with light depleted in the 320-400 nm region of the spectrum and exposed to UV-B died. Low levels of UV-B did neither affected hypocotyl elongation nor amounts of free IAA in sunflower plants grown under low (LL; 143 {mu}mol m{sup -2}s{sup -1}) or high PAR (HL; 800 {mu}mol m{sup -2}s{sup -1}). Three times more daily UV-B increased the amount of free IAA, but inhibited hypocotyl elongation. Higher F{sub v}/F{sub max} and F690/F735, Chl a and carotenoids were found in plants exposed to low UV-B. Indeed, UV-B can be harmful but may also have enhancing effects on plants. (au) (114 refs.).}
place = {Sweden}
year = {1992}
month = {Dec}
}
title = {Effects of ultraviolet radiation on Hibiscus rosa-sinensis, Beta vulgaris and Helianthus annuus}
author = {Panagopoulos, I}
abstractNote = {It is believed that increased levels of ultraviolet B-radiation (UV-B;280-320 nm) will result in serious threat to plant. In the present study the effects of UV (particularly UV-B) were studied on chlorophyll fluorescence, ultraweak luminescence (UL) and plant growth. Parameters related to light emission were determined, and the effects of UV-B on hypocotyl elongation and levels of free IAA were examined. The plants were grown in greenhouse or in growth chambers and exposed to short or long term UV-B simulating different levels of ozone depletion. Short exposure of Hibiscus leaves to UV resulted in a gradual increase in both UL and peroxidase activity followed by a decline after 72 h and a decrease in variable chlorophyll fluorescence. The action of UV-B on sugar beet plants depended on light quality and irradiance and infection by Cercospora beticola Sacc. The interaction between UV-B and the disease resulted in a large reduction of dry weight and enhanced UL. The lowest Chl a and growth was found in plants grown under low irradiance and exposed to UV-B supplemented with UV-A (320-400 nm). UVB also inhibited photosystem II, increased UL and peroxidase activity. Under relatively high PAR, UV-B increased dry weight of laminae and UL but no effect on Chl content. Sugar beet plants grown with light depleted in the 320-400 nm region of the spectrum and exposed to UV-B died. Low levels of UV-B did neither affected hypocotyl elongation nor amounts of free IAA in sunflower plants grown under low (LL; 143 {mu}mol m{sup -2}s{sup -1}) or high PAR (HL; 800 {mu}mol m{sup -2}s{sup -1}). Three times more daily UV-B increased the amount of free IAA, but inhibited hypocotyl elongation. Higher F{sub v}/F{sub max} and F690/F735, Chl a and carotenoids were found in plants exposed to low UV-B. Indeed, UV-B can be harmful but may also have enhancing effects on plants. (au) (114 refs.).}
place = {Sweden}
year = {1992}
month = {Dec}
}