CENTRE ON THE PROBLEMS OF ECOLOGY AND PRODUCTIVITY OF FORESTS

RUSSIAN ACADEMY OF SCIENCES

A. G. Molchanov Intensity of Photosynthesis in Quercus robur Phenological Forms under Moisture Deficit // Forest Science (Lesovedenie). 2012. No 4. С.31-38.

The studies were conducted at the Tellerman Forestry of the Institute of Forestry, Russian Academy of Sciences (Voronezh region). The sample plots were located in a 250-year-old oak forest (quality class III) on the south-facing slope with a groundwater table of about 8-9 m, where the late-leafing form of oak trees predominated. The roots of this form reach the groundwater capillary fringe. At the same time, the studies were carried out in a solonetz oak forest of quality class III with the early-leafing form of oak trees whose roots were mainly spread in the shallow soil layer (10-40 cm). The investigations were carried out under insufficient humidity when the water potential of leaves was 1.6 MPa. Based on the daily course of photosynthesis and light curves of photosynthesis obtained in cloudy and fair with some cloud days, it was concluded that the early-leafing oak form endured a water deficit more easily as compared to the late-leafing form did. This circumstance explains the fact that the early-leafing form of oak is restricted to dry and very dry sites. In more favorable sites, this form cannot compete with the late-leafing one, since it is more often damaged by early spring frosts and phyllophages of the early spring complex.

Early-leafing form of oak, late-leafing form of oak, photosynthesis, moisture deficit, south forest-steppe..

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