Limits...
High-susceptibility of photosynthesis to photoinhibition in the tropical plant Ficus microcarpa L. f. cv. Golden Leaves.

Takahashi S, Tamashiro A, Sakihama Y, Yamamoto Y, Kawamitsu Y, Yamasaki H - BMC Plant Biol. (2002)

Bottom Line: We compared the response of photosynthetic activities to strong light between GL and its wild-type (WT, Ficus microcarpa L. f.).In contrast, WT did not show any substantial changes of Fv/Fm values throughout the day (between 0.82 and 0.78).We conclude that the photosynthetic apparatus of GL is more highly susceptible to photoinhibition than that of WT.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Cell and Functional Biology, Faculty of Science, University of the Ryukyus, Okinawa, Japan. takahashishunichi@hotmail.com

ABSTRACT

Background: The tropical plant Ficus microcarpa L. f. cv. Golden Leaves (GL) is a high-light sensitive tropical fig tree in which sun-leaves are yellow and shade-leaves are green. We compared the response of photosynthetic activities to strong light between GL and its wild-type (WT, Ficus microcarpa L. f.).

Results: Field measurements of maximum photosystem II (PSII) efficiency (Fv/Fm) of intact sun-leaves in GL showed that photo synthetic activity was severely photoinhibited during the daytime (Fv/Fm = 0.46) and subsequently recovered in the evening (Fv/Fm = 0.76). In contrast, WT did not show any substantial changes of Fv/Fm values throughout the day (between 0.82 and 0.78). Light dependency of the CO2 assimilation rate in detached shade-leaves of GL showed a response similar to that in WT, suggesting no substantial difference in photosynthetic performance between them. Several indicators of photoinhibition, including declines in PSII reaction center protein (D1) content, Fv/Fm value, and O2 evolution and CO2 assimilation rates, all indicated that GL is much more susceptible to photoinhibition than WT. Kinetics of PAM chlorophyll a fluorescence revealed that nonphotochemical quenching (NPQ) capacity of GL was lower than that of WT.

Conclusion: We conclude that the photosynthetic apparatus of GL is more highly susceptible to photoinhibition than that of WT.

Show MeSH

Related in: MedlinePlus

Photoinhibition of GL observed in the field-grown conditions. Top panel, a typical diurnal change in PPFD (▪) on the leaves and atmospheric temperature (□) in the field. Bottom panel, a diurnal change in maximum PSII efficiency of intact attached leaves in the field. (•, blue), WT; (Δ red), GL. Fv/Fm value was measured as PSII efficiency with a portable chlorophyll a fluorometer (PAM-2000). Each data point is the mean of 10 separate measurements ± SD.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC102767&req=5

Figure 2: Photoinhibition of GL observed in the field-grown conditions. Top panel, a typical diurnal change in PPFD (▪) on the leaves and atmospheric temperature (□) in the field. Bottom panel, a diurnal change in maximum PSII efficiency of intact attached leaves in the field. (•, blue), WT; (Δ red), GL. Fv/Fm value was measured as PSII efficiency with a portable chlorophyll a fluorometer (PAM-2000). Each data point is the mean of 10 separate measurements ± SD.

Mentions: Figure 2 shows diurnal change of maximum PSII efficiency (Fv/Fm) in field grown attached sun-leaves collected from the canopy. Chlorophyll content of sun-leaves in GL (yellow) was 0.05 g m-2 and that in WT (green) was 0.44 g m-2. There was no significant difference between GL and WT in Fv/Fm values measured early in the morning (6 a.m.). The value of Fv/Fm in GL decreased from 0.77 (6 a.m.) to 0.46 (2 p.m.) and subsequently recovered to 0.74 in the evening (6 p.m.). In contrast to GL, Fv/Fm values in WT were almost constant throughout a day. Shade-leaves of GL(green), collected from the inside of tree, did not show any decrease in the Fv/Fm value (data not shown). These data obtained in the field conditions suggest that GL is highly susceptible to high-light.


High-susceptibility of photosynthesis to photoinhibition in the tropical plant Ficus microcarpa L. f. cv. Golden Leaves.

Takahashi S, Tamashiro A, Sakihama Y, Yamamoto Y, Kawamitsu Y, Yamasaki H - BMC Plant Biol. (2002)

Photoinhibition of GL observed in the field-grown conditions. Top panel, a typical diurnal change in PPFD (▪) on the leaves and atmospheric temperature (□) in the field. Bottom panel, a diurnal change in maximum PSII efficiency of intact attached leaves in the field. (•, blue), WT; (Δ red), GL. Fv/Fm value was measured as PSII efficiency with a portable chlorophyll a fluorometer (PAM-2000). Each data point is the mean of 10 separate measurements ± SD.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC102767&req=5

Figure 2: Photoinhibition of GL observed in the field-grown conditions. Top panel, a typical diurnal change in PPFD (▪) on the leaves and atmospheric temperature (□) in the field. Bottom panel, a diurnal change in maximum PSII efficiency of intact attached leaves in the field. (•, blue), WT; (Δ red), GL. Fv/Fm value was measured as PSII efficiency with a portable chlorophyll a fluorometer (PAM-2000). Each data point is the mean of 10 separate measurements ± SD.
Mentions: Figure 2 shows diurnal change of maximum PSII efficiency (Fv/Fm) in field grown attached sun-leaves collected from the canopy. Chlorophyll content of sun-leaves in GL (yellow) was 0.05 g m-2 and that in WT (green) was 0.44 g m-2. There was no significant difference between GL and WT in Fv/Fm values measured early in the morning (6 a.m.). The value of Fv/Fm in GL decreased from 0.77 (6 a.m.) to 0.46 (2 p.m.) and subsequently recovered to 0.74 in the evening (6 p.m.). In contrast to GL, Fv/Fm values in WT were almost constant throughout a day. Shade-leaves of GL(green), collected from the inside of tree, did not show any decrease in the Fv/Fm value (data not shown). These data obtained in the field conditions suggest that GL is highly susceptible to high-light.

Bottom Line: We compared the response of photosynthetic activities to strong light between GL and its wild-type (WT, Ficus microcarpa L. f.).In contrast, WT did not show any substantial changes of Fv/Fm values throughout the day (between 0.82 and 0.78).We conclude that the photosynthetic apparatus of GL is more highly susceptible to photoinhibition than that of WT.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Cell and Functional Biology, Faculty of Science, University of the Ryukyus, Okinawa, Japan. takahashishunichi@hotmail.com

ABSTRACT

Background: The tropical plant Ficus microcarpa L. f. cv. Golden Leaves (GL) is a high-light sensitive tropical fig tree in which sun-leaves are yellow and shade-leaves are green. We compared the response of photosynthetic activities to strong light between GL and its wild-type (WT, Ficus microcarpa L. f.).

Results: Field measurements of maximum photosystem II (PSII) efficiency (Fv/Fm) of intact sun-leaves in GL showed that photo synthetic activity was severely photoinhibited during the daytime (Fv/Fm = 0.46) and subsequently recovered in the evening (Fv/Fm = 0.76). In contrast, WT did not show any substantial changes of Fv/Fm values throughout the day (between 0.82 and 0.78). Light dependency of the CO2 assimilation rate in detached shade-leaves of GL showed a response similar to that in WT, suggesting no substantial difference in photosynthetic performance between them. Several indicators of photoinhibition, including declines in PSII reaction center protein (D1) content, Fv/Fm value, and O2 evolution and CO2 assimilation rates, all indicated that GL is much more susceptible to photoinhibition than WT. Kinetics of PAM chlorophyll a fluorescence revealed that nonphotochemical quenching (NPQ) capacity of GL was lower than that of WT.

Conclusion: We conclude that the photosynthetic apparatus of GL is more highly susceptible to photoinhibition than that of WT.

Show MeSH
Related in: MedlinePlus