The use of physiological characteristics for comparison of organic compounds phytotoxicity.

The influence of intact (FLT) and photomodified (phFLT) fluoranthene (0.05, 0.5 and 5 micromol l(-1)) and herbicide Basagran (5, 20, 35 and 50 nmol l(-1)) on the germination, growth of seedlings and photosynthetic processes in pea plants (Pisum sativum L., cv. Garde) was investigated. The germination was significantly inhibited already by the lowest concentration (0.05 micromol l(-1)) of FLT and phFLT, while Basagran caused inhibition only in higher concentrations (35 and 50 nmol l(-1)). The growth of roots was significantly inhibited by higher concentration 5 micromol l(-1) of both FLT and phFLT and the shoot of seedlings was significantly influenced only by photomodified form. The length of root and shoot was inhibited already by concentration 5 nmol l(-1) of Basagran. Organic compounds applied on chloroplasts suspension influenced primary photochemical processes of photosynthesis. In chlorophyll fluorescence parameters, the significant increase of F(0) values and the decrease of F(V)/F(M) and Phi(II) values by application of FLT (0.5 and 5 micromol l(-1)) and phFLT (0.05, 0.5 and 5 micromol l(-1)) was recorded. The maximum capacity of PSII (F(V)/F(M)) was influenced by the highest (50 nmol l(-1)) and the effective quantum yield of PSII (Phi(II)) already by the lowest (5 nmol l(-1)) concentration of Basagran. Hill reaction activity decreased and was significantly inhibited by higher concentration (0.5 and 5 micromol l(-1)) of FLT and phFLT and already by the lowest concentration (5 nmol l(-1)) of Basagran.