Net Photosynthesis, Electron Transport Capacity, and Ultrastructure of Pisum sativum L. Exposed to Ultraviolet-B Radiation

Six pyridyl derivatives [benzylviologen, 2-anilinopyridine, 1,2-bis(4-pyridyl)ethane, 1,2-bis(4-pyridyl)ethylene, 2-benzoylpyridine, and 2-benzylaminopyridine] and five heme-iron derivatives [hemoglobin, hemin, hematin, ferritin, and ferrocene] were screened for their potential to counteract paraquat (1,1′-dimethyl-4.4′-bipyridinium ion) toxicity on pea (Pisum sativum L.) isolated chloroplasts. The H2O → methylviologen(MV)/O2 and H2O → ferredoxin(Fd)/NADP+ were two Hill reactions assayed with these compounds. Antagonists of paraquat toxicity should inhibit the first Hill reaction but not the latter. AU pyridyl derivatives examined did not inhibit the reaction H2O → MV/O2. Ferritin and ferrocene were also ineffective as inhibitors of this reaction. Hemoglobin inhibited the reaction H2O → MV/O2 without inhibiting the reaction H2O → Fd/NADP+, providing protection to pea chloroplasts against paraquat. Hemin and hematin inhibited both Hill reactions examined. They also inhibited H2O → diaminodurene(DAD)ox and durohydro- quinone → MV/O2 Hill reactions but not the dichlorophenol indophenolred → MV/O2 and DADred → MV/O2 Hill reactions. These results suggest that hemin and hematin are inhibiting the photo- synthetic electron transport in the plastoquinone-pool region.

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Counteraction of Paraquat Toxicity at the Chloroplast Level

Zeitschrift für Naturforschung C ◽

10.1515/znc-1987-7-814 ◽

1987 ◽

Vol 42 (7-8) ◽

pp. 824-828 ◽

Cited By ~ 2

Author(s):

Brad L. Upham ◽

Kriton K. Hatzios

Keyword(s):

Electron Transport ◽

Pisum Sativum ◽

Photosynthetic Electron Transport ◽

Heme Iron ◽

Hill Reaction ◽

Ion Toxicity ◽

Plastoquinone Pool ◽

Pisum Sativum L ◽

Paraquat Toxicity ◽

Isolated Chloroplasts

Six pyridyl derivatives [benzylviologen, 2-anilinopyridine, 1,2-bis(4-pyridyl)ethane, 1,2-bis(4- pyridyl)ethylene, 2-benzoylpyridine, and 2-benzylaminopyridine] and five heme-iron derivatives [hemoglobin, hemin, hematin, ferritin, and ferrocene] were screened for their potential to coun- teract paraquat (1,1′-dimethyl-4.4′-bipyridinium ion) toxicity on pea (Pisum sativum L.) isolated chloroplasts. The H2O -> methylviologen(MV)/O2 and H2O → ferredoxin(Fd)/NADP+ were two Hill reactions assayed with these compounds. Antagonists of paraquat toxicity should inhibit the first Hill reaction but not the latter. All pyridyl derivatives examined did not inhibit the reaction H2O → MV/O2. Ferritin and ferrocene were also ineffective as inhibitors of this reaction. Hemoglobin inhibited the reaction H2O → MV/O2 without inhibiting the reaction H2O → Fd/NADP+, providing protection to pea chloroplasts against paraquat. Hemin and hematin inhibited both Hill reactions examined. They also inhibited H2O → diaminodurene(DAD)ox and durohydro-quinone → MV/O2 Hill reactions but not the dichlorophenol indophenolred → MV/O2 and DADred → MV/O2 Hill reactions. These results suggest that hemin and hematin are inhibiting the photosynthetic electron transport in the plastoquinone-pool region.

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Importance of oxidative electron transport over oxidative phosphorylation in optimizing photosynthesis in mesophyll protoplasts of pea (Pisum sativum L.)

Physiologia Plantarum ◽

10.1034/j.1399-3054.1999.105321.x ◽

1999 ◽

Vol 105 (3) ◽

pp. 546-553 ◽

Cited By ~ 46

Author(s):

K. Padmasree ◽

A. S. Raghavendra

Keyword(s):

Electron Transport ◽

Pisum Sativum ◽

Oxidative Phosphorylation ◽

Mesophyll Protoplasts ◽

Pisum Sativum L

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Does salicylic acid mitigate the adverse effects of temperature and ultraviolet-B radiation on pea ( Pisum sativum ) plants?

Environmental and Experimental Botany ◽

10.1016/j.envexpbot.2015.09.002 ◽

2016 ◽

Vol 122 ◽

pp. 39-48 ◽

Cited By ~ 17

Author(s):

Ashley B. Martel ◽

Mirwais M. Qaderi

Keyword(s):

Salicylic Acid ◽

Pisum Sativum ◽

Adverse Effects ◽

Ultraviolet B ◽

Ultraviolet B Radiation ◽

Effects Of Temperature

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The effects of ultraviolet-B radiation and carbon dioxide on growth and photosynthesis of tomato

Canadian Journal of Botany ◽

10.1139/b97-022 ◽

1997 ◽

Vol 75 (2) ◽

pp. 213-219 ◽

Cited By ~ 6

Author(s):

Xiuming Hao ◽

Beverley A. Hale ◽

Douglas P. Ormrod

Keyword(s):

Lycopersicon Esculentum ◽

Leaf Area ◽

Plant Height ◽

Net Photosynthesis ◽

Dry Weight ◽

Ultraviolet B ◽

Radiation Level ◽

Ultraviolet B Radiation ◽

Lycopersicon Esculentum Mill ◽

Uv Absorbing Compounds

Tomato (Lycopersicon esculentum Mill.) plants were exposed, in controlled environments with 2.7 kJ/(m2 ∙ day) background ultraviolet-B (UV-B) radiation from fluorescent and incandescent lamps, to ambient (380 μL ∙ L−1) or elevated (600 μL−1) CO2 combined with a total of 7.2 or 13.1 kJ/(m2 ∙ day) UV-B radiation to determine effects on growth and photosynthesis. Ten consecutive days of exposure to the higher level of UV-B significantly reduced total and stem dry weight, leaf area, and plant height compared with the lower level. Only leaf area and plant height were significantly reduced after 19 consecutive days of exposure. To investigate whether plants recover from UV-B damage, the UV-B exposures were halted for 3 days after 19 days of UV-B exposure and then restarted for a further 2 days. The largest reduction in plant growth was found after 3 days with no UV-B followed by 2 days of the higher level of UV-B. Plants did not recover from UV-B damage during the 3 days with background UV-B. Significant CO2xUV-B interactions were detected on stem dry weight after 10 consecutive days of the higher level of UV-B and on total dry weight, leaf dry weight, stem dry weight, and plant height after 3 days with no UV-B followed by 2 days of the higher level of UV-B. The higher dose of enhanced UV-B resulted in more severe damage at 600 μL ∙ L−1 CO2, than at ambient CO2. The higher level of UV-B did not affect the leaf net photosynthesis rate on a leaf area basis, although this UV-B level may have inhibited tomato growth through reducing the photosynthetic area. UV-absorbing compounds in leaves in the highest UV-B radiation level for 19 days were greater than for leaves with the lower dose. These UV-absorbing compounds in the higher UV-B dose diminished more than in the lower dose plants during the 3 days without UV-B. The UV-absorbing compounds maintained by plants exposed to the highest level of UV-B radiation may have protected plants from UV-B damage, particularly between 10 and 19 consecutive days of exposure. Key words: CO2, growth, Lycopersicon esculentum Mill., photosynthesis, tomato, ultraviolet-B radiation (UV-B), UV-absorbing compounds.

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