THE EFFECT OF CO2 CONCENTRATION AND WATER SUPPLY ON PHOTOSYNTHESIS, DRY MATTER PRODUCTION AND NITRATE CONCENTRATIONS OF KOHLRABI (BRASSICA OLERACEA VAR. GONGYLODES L.) – REFEREED PAPER –

Kohlrabi plants were grown under controlled environmental conditions at two levels of CO2 concentration ( 300 μl.l^-1 and 900 μl.l^-1 ). They were supplied with modified Hoagland solution and subjected to three levels of water supply ( 100, 50 and 25% ) for three weeks.

At high CO2 concentration plants produced more leaf area, dry matter and had higher photosynthetic rates than those grown at low CO2. This effect was more pronounced at low water supply though the absolute rates of growth, dry matter, photosynthesis, transpiration and stomatal conductance were reduced.

The nitrate concentration in all plant organs were significantly reduced at high CO2. Low water supply resulted in increased NO3 concentrations especially in lamina and tuber.

These results indicate that CO2 enrichment and adequate water supply can reduce nitrate concentration considerably in Kohlrabi plants.

Possible control mechanisms and effects of CO2 on dry matter production and nitrogen metabolism at water stress are discussed.

IV International Symposium on CO2 in Protected Cultivation

R. Sritharan, F. Lenz

https://doi.org/10.17660/ActaHortic.1990.268.3