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

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 (F_v/F_m) of intact sunleaves in GL showed that photo synthetic activity was severely photoinhibited during the daytime (F_v/F_m = 0.46) and subsequently recovered in the evening (F_v/F_m = 0.76). In contrast, WT did not show any substantial changes of F_v/F_m 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, F_v/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.

Digital Object Identifer:10.1186/1471-2229-2-2
Published with permission from the copyright holder. This is the institute's copy, as published in BMC Plant Biology, 2002, 2:2 (2 April 2002).
Publisher URL: http://dx.doi.org/10.1186/1471-2229-2-2
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