High temperature effect on microflora of radish root-inhabited zone and nutrient solutions for radish growth Original Research Article

The effect of high temperatures (35 and 45 °C) on microflora of the root zone of radish plants grown in phytotron was evaluated by the response of microorganisms from 9 indicator groups. Phytotron air temperature elevated to 35 °C for 20 hours caused no significant changes in qualitative and quantitative composition of the root microflora in experimental plants. By the end of the experiment, the species diversity of microflora had changed. The amount of phytopathogenic microorganisms decreased which can be interpreted as more stable co-existence of microflora with plants. The numbers of microbes from other indicator groups was in dynamic equilibrium. The plantsʹ condition did not deteriorate either. Exposure to the temperature of 45 °C for 7 hours have been found to change the numbers and species diversity in the radish root zone microflora. The microorganisms were observed to increase their total numbers at the expense of certain indicator groups. Bacteria increased spore forms at the stage of spores. Colon bacillus bacteria of increased their numbers by the end of experiment by an order. By the end of experiment the roots of experiment plants had microscopic fungi from Mucor, Aspergillus, Trichoderma, Cladosporium genera. The observed changes in the microbial complex seem to be associated with the changes of root emissions and general deterioration of the plantsʹ condition. It is suggested that the response of the microorganisms can be indicative of the condition of plants under investigation.