In Broadleaved Evergreens Variations in Fv/Fm Induced by Photoinhibition are Coupled to Reductions in PSII RC Unit Size
Different sources of stress, when coupled to high light fluence, produce photoinhibitive damage on broadleaved evergreens at irradiations which are 4–5 times higher than reported on annual leaves. Quantum yield of PSII photochemistry Qy(p) as indicated by the ratio Fv/Fm at 692nm (Kitajima and Butler) was found to be quite a convenient probe of photoinhibitive damage; Bjorkman3 on Hedera canariensis, and same other authors on different species found highly signifiant relationship between quantum yield for oxygen evolution, Qy(ox) and Qy (p). The same procedure when applied to our plants resulted however in a trend lowered by a constant factor in respect to those experiences (fig.1).
KeywordsQuantum Yield Nitrogen Starvation PSII Photochemistry Primary Photochemistry Annual Leaf
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