EFFECT OF DIFFERENT GROWING SUBSTRATES ON THE PHOTOSYNTHESIS PARAMETERS AND FRUIT YIELD OF GREENHOUSE-GROWN TOMATO

In the period 2009-2011, a study was conducted in a greenhouse, using fertigation, to determine the photosynthetic activity of leaves and tomato fruit yield of plants grown on different substrates. The plants were grown on rockwool slabs, 15 dm(3) in volume, and slabs of the same volume made of the following straw chaff: rape straw; rape straw + peat (3: 1); rape straw + pine bark (3:1); triticale straw; triticale straw + peat (3: 1), triticale straw + pine bark (3:1). Two tomato plants were grown on each slab, leaving 22 fruit clusters on each plant during the period from February to October. The obtained results showed that photosynthetic pigment content, chlorophyll fluorescence, rate of photosynthesis and substomatal CO2 concentration in the leaves of tomato grown on rockwool and on rape or triticale straw chaff substrates did not differ statistically significantly. No significant differences were found in total yield of tomato fruits. Peat or pine bark addition to the rape or triticale straw substrates had no significant effect on the change in their usefulness. The substrates used differed only in the content of total phenolic compounds after tomato harvest. The substrates prepared from triticale straw and its mixture with peat and bark as well as from rape straw with bark were characterized by a higher level of phenolic compounds than the other substrates. In the opinion of the present authors, substrates of rape or triticale straw alone, and even more so with the addition of peat or pine bark are not inferior in any way to commonly used rockwool.