The effects of soil or in vitro grown plants, pretreatment conditions, donor tissue and isolation procedure on protoplast yield from cotyledons and leaves of tomato cv. 'Perkoz' and 'Zorza' were studied. The highest protoplast yield of 1.5 x l0(7) /g FW was obtained from leaves of in vitro grown plants. Low light intensity during donor plants in vitro culture and dark pretreatment were essential for successful protoplast isolation while cold pretreatment was not. Tissue preplasmolysis prior to transfer to enzyme mixture increased 4-fold the number of isolated protoplasts. Glycine and bovine serum albumin in the isolation medium did not significantly influence the protoplast yield.
The reactions of strawberry plants to infection with B. cinerea and treatment with salicylic acid has been studied. Infection of leaves with B. cinerea resulted in early increases in active oxygen species generation, superoxide dismutase and peroxidase activities and phenolic compounds content. Some increases of the above reactions were noticed in plants treated with salicylic acid but not in the plants treated with S A and then later infected with B. cinerea.
Using CM-Sepharose column chromatography it was shown that Fusarium avenaceum produced two forms of endo-polygalacturonase, one exo-polygalacturonase and two forms of endo-xylanase in infected lupin roots. A glycoprotein obtained from lupin seedlings inhibited endo-polygalacturonases, exo-polygalacturonases and xylanases but more the first ones. Two forms of endo-polygalacturonase did not differ in their sensitivity to the glycoprotein.