EXPRESSION OF CUCUMBER STRESS-RELATED ANIONIC PEROXIDASES DURING FLOWER DEVELOPMENT OR A CRYPTIC INFECTIVE PROCESS

The striking diversity in the expression pattern of the stress-related anionic peroxidase was observed during development of female cucumber flower. While the isoenzyme Prx3 was accumulated constitutively in th e course of flower development, the expression patterns of other two i soenzymes (Prx1 and Prx2) were restricted to the period after flower o pening. The virus infection was simulated by careful opening of the in tact female flower buds 3 d before anthesis followed by exposition to the glasshouse environment for 3 d. The results obtained in this exper iment revealed a marked accumulation of the isoenzyme Prx1 and Prx2 at anthesis. Under normal flower development, the pistils did not accumu late these isoenzymes at this stage. In contrast, the pattern of expre ssion of Prx3 as well as of the pistil-specific peroxidase isoenzyme r emained unchanged, confirming a constitutive type of expression. Besid e the pistil, a 3-d exposition of the stripped flowers resulted in a m arked accumulation of Prx1 and Prx2 isoenzymes also in both adjacent n ewer organs - the ovary and the pedicel. At the same time of the norma l development of female flower these organs did not accumulate these i soenzymes.