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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.

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Photograph of Ficus microcarpa L. f. (WT) and Ficus microcarpa L. f. cv. Golden Leaves (GL). Each branch was collected from canopy of mature trees grown in the field. Characteristic yellow leaves are observed only in sun-leaves of GL.
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Figure 1: Photograph of Ficus microcarpa L. f. (WT) and Ficus microcarpa L. f. cv. Golden Leaves (GL). Each branch was collected from canopy of mature trees grown in the field. Characteristic yellow leaves are observed only in sun-leaves of GL.

Mentions: GL is a cultivar of the tropical fig tree Ficus microcarpa L. f. (WT) that is natively distributed in subtropical/tropical regions of Asia and Oceania. A significant characteristic of GL is the presence of yellow leaves that contain high amounts of flavonoids and negligible amounts of chlorophyll and carotenoids [21]. The reduced content of photosynthetic pigments in the yellow leaves can be increased by shading them from high-light. In shade conditions, therefore, GL exhibits normal green leaves which cannot be morphologically distinguished from WT leaves (Fig. 1). We have suggested that high susceptibility of GL to photoinhibition could explain the phenomenon [21]. However, there was no direct evidence available to show the susceptibility of GL to photoinhibition.


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)

Photograph of Ficus microcarpa L. f. (WT) and Ficus microcarpa L. f. cv. Golden Leaves (GL). Each branch was collected from canopy of mature trees grown in the field. Characteristic yellow leaves are observed only in sun-leaves of GL.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 1: Photograph of Ficus microcarpa L. f. (WT) and Ficus microcarpa L. f. cv. Golden Leaves (GL). Each branch was collected from canopy of mature trees grown in the field. Characteristic yellow leaves are observed only in sun-leaves of GL.
Mentions: GL is a cultivar of the tropical fig tree Ficus microcarpa L. f. (WT) that is natively distributed in subtropical/tropical regions of Asia and Oceania. A significant characteristic of GL is the presence of yellow leaves that contain high amounts of flavonoids and negligible amounts of chlorophyll and carotenoids [21]. The reduced content of photosynthetic pigments in the yellow leaves can be increased by shading them from high-light. In shade conditions, therefore, GL exhibits normal green leaves which cannot be morphologically distinguished from WT leaves (Fig. 1). We have suggested that high susceptibility of GL to photoinhibition could explain the phenomenon [21]. However, there was no direct evidence available to show the susceptibility of GL to photoinhibition.

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