THE EFFECTS OF MILDEW INFECTIONS ON THE CARBON BALANCE OF YOUNG LEAVES OF BLACK CURRANT (RIBES NIGRUM L.)

Graduated levels of mildew infections were established in sprayed and unsprayed plants of Ribes nigrum. Infection levels were judged on single young leaves of terminal shoots on a scale from 1 (no infection) to 5 (fully infected). Carbon gas exchange was measured on leaves at all infection levels.
The various levels did not affect the general shape of the light response curve.
When control leaves were compared with infection up to level 4, no effect could be observed on the photosynthetic rate at light saturation.
However, on highly infected leaves (level 5) a 40 % reduction in photosynthetic rate was observed.
Neither the respiration levels during dark periods nor the light compensation point was affected by the infection.
Overall, respiration levels were very low and light compensation was reached at light intensities of 30-40 μmol PPFD m^-2s^-1 and apparently the mildew infections did not affect carbon losses to a significant degree.
The effect of mildew on leaf photosynthetic rate was low or not existent, unless the leaf was fully infected.

Euro Berry Symposium – COST-Action 836 Final Workshop

T.B. Toldam-Andersen, P. Braun, H. Lindhard Pedersen

Ribes nigrum L., gas exchange, photosynthesis, mini cuvette systems

https://doi.org/10.17660/ActaHortic.2004.649.55