ASSESSMENT OF RECOVERY DYNAMICS OF PHYSIOLOGICAL AND BIOCHEMICAL INDICATORS IN LEAVES OF PEDUNCULATE OAK (QUERCUS ROBUR) FOLLOWING HEAT SHOCK
Petru CUZA, Nina ZDIORUC, Nicolai PLATOVSCHII, Universitatea de Stat din Moldova
Abstract
The leaves of pedunculate oak (Quercus robur L.) were collected from the Plaiul Fagului Reserve, representing
provenances from Edineț (north), Hârjauca (center), and Baimaclia (south). The study assessed the recovery dynamics of the chlorophyll index, the maximum relative yield of PSII, and the levels of phenols, tannins, and water in
the leaves following thermal shock (50°C for 20 and 40 minutes). Over the ten-day recovery period, the chlorophyll
index displayed low and variable values, with an increasing trend along the south-to-north gradient, suggesting more
pronounced senescence processes in the leaves from Baimaclia. The Edineț provenance stood out with a significantly
higher chlorophyll index and slightly elevated levels of the maximum relative yield of PSII, phenolic compounds,
tannins, and leaf water content compared to the other provenances, indicating a more effective adaptation to thermal
shock. Distant provenances, Edineț and Baimaclia, exhibited more pronounced adaptive responses compared to Hârjauca, which is geographically closer to the cultivation site.
Keywords: Quercus robur, leaves, provenance, heat shock, recovery, chlorophyll index, maximum relative yield of
PSII, phenols, tannins, water content.
