engleski

Chlorophylls content and photosynthetic performance in Aleppo pine needles

Aleppo pine (Pinus halepensis L.) is widely spread Mediterranean woody species. Its natural and cultivated populations can be frequently found in the coastal area of the Adriatic Sea. Usually, needles fall down after the second year, what can be the reason for substantial crown defoliation under extreme environmental stress. The aim of this investigation was to compare the chlorophylls content and photosynthetic performance in current- year (CY) and previousyear (PY) A. pine needles. Chlorophylls concentrations were determined spectrophotometrically and the photosynthetic performance was determined by measuring the increase in chlorophyll a fluorescence (JIP test). Results revealed that concentrations of chlorophylls a and b were almost two folded in PY needles compared to CY ones, what was statistically significant. Chlorophylls a to b ratio and values of the maximum quantum yield of the photosystem II (Fv/Fm) showed no statistical significance between CY and PY needles. However, performance index (PIABS) was significantly higher in CY needles compared to PY ones. Based on the presented results it can be concluded that despite of considerably lower chlorophylls content, CY needles reveled enhanced photosynthetic performance than older needles. The analysis of JIP test parameters showed that the main reason for this was better utilization of absorbed light energy in CY needles due to their more competent photosynthetic electron transport, in comparison to PY needles.

Aleppo pine, chlorophyll a fluorescence, photosynthesis, photosystem II, Pinus

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