RELATIONSHIP BETWEEN SOIL WATER CONTENT, LEAF WATER POTENTIAL AND FRUIT GROWTH DURING DIFFERENT FRUIT GROWING PHASES OF PEACH TREES

Leaf water potential (₁) before sunrise was a useful indicator of available water content in the soil; these variables were well correlated (r = 0.94).

During the first stress cycle (pit-hardening stage), a direct relationship (r = 0.94) between leaf water potential and fruit growth was noticed.

During the second stress cycle (third stage) it was noticed that the three parameters measured, i.e. predawn ₁, available soil water and fruit growth, were in multiple correlation with r = 0.99.

After field capacity had been re-established, leaf water potential recovered rapidly but stomatal opening recovered more slowly. This stomatal inertia is responsible, at least partly, for the incomplete leaf water potential recovery.

A week after re-establishment of field capacity fruit size on the stressed plants was still smaller. Slower fruit growth was more marked in the second stress cycle, that is before the fruit ripening stage.

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