Use of the method of measurement of chlorophyll fluorescence to determine the phytotoxicity of mesotrione in poppy (Papaver somniferum) in relation to application factors [Využití metody měření fluorescence chlorofylu ke stanovení fytotoxicity mesotrioneu máku setého {papaver somniferum ve vztahu kaplikačním faktorům]

The aim of the research work was to evaluate phytotoxicity of mesotrione in poppy (Papaver somniferum). The amount of spraying water (150,300 and 4501 per hectare) was compared as well. In the end,the different growth stimulators (Atonik - 0.6 1.ha-1,Route - 0.8 l.ha-1) and the adjuvants (Atplus 463 - 0.5% solution,Silwet 77 - 0.1.ha-1) wre tested. Degree of phytotoxicity of individual variants was assessed by measuring chlorophyll fluorescence (parameter: maximum quantum yield of electron transport in photosystem II - QY) in 1st to 21st day after treatment. The results showed that the application of mesotrione caused phytotoxicity on poppy plants. The most significant phytotoxicity is evident at doses of 4501 spraying water per hectare. Addition of growth stimulators and adjuvants increases the phytotoxicity (decreases the value of QY) compared to the herbicide application itself. The mesotrione reduced the weight of dry plants by 15% (1501 of spraying water),1% (3001 of spraying water) and 64% (4501 of spraying water) compared to control variant.