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Quantum yield by the intertidal seagrass Zostera noltii
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Abstract(s)
The maximum (Fv/FM) and the effective (F'v/F'm) quantum ise efficinecies of PSII were investigated in the intertidal seagrass Zostera noltii from Ria Formosa coastal lagoon (southern Portugal). Modulated chlorophyll fluorescence measurements were conducted monthly in both neap and spring tides over a yearly cycle. Other fluorescence parameters such as the Stern-Volmer non-photochemical quenching (NPQ) and the novel parameter LNP (which expresses the general decrease in PSII photochemical activity in the light) were derived from quantum use efficiency measurements. In all the samplings Fv/Fm presented a typical midday depression, which amplitude was higher during neap tides, when low tide occurs at noon and the plants are air-exposed. Annual patterns also emerged , revealing higher maximum quantum use efficiencies in winter and early spring, under mild temperatures and moderate irradiances. During summer months the maximum quantum use efficiency was at its lowest, most likely due to increased stress levels imposed by the combination of high temperature and strong irradiances. Relationships between quantum use efficiency (as revealed by chlorophyll fluorescence data) and critical environmental parameters (irradiance, temperature, air exposure) were explored through multifactorial analysis.
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Keywords
Seagrass Zostera noltii Quantum use efficiency Chlorophyll fluorescence
Citation
Silva J, Barrote I, Santos R (2009). Quantum use efficiency by the intertidal seagrass Zostera noltii. In Proceedings of the Mediterranean Seagrass Workshop 09, Hvar, Croatia (G Di Carlo, A Calladine and A Zuljevic eds). p.43