Changes of respiration intensity and chlo'rophyll content in needles of Normay spruce (Picea abies L. Karst) seedlings treated with 2,4,5-T and dalapon

Jan Tonecki


The results of investigations on the effect of 2,4,5-T (butyl ester of 2,4,5-trichlorophenoxy acetic acid) and dalapon (sodium salt of 2,2-dichloropropionic acid) on chlorophyll content and rate of respiration in needles of spruce seedlings, treated with different concentrations of both herbicides before bud development and during bud formation' are presented. 2,4,5-T and dalapon decreased chlorophyll a and b content in the needles. The chlorophyll a : b ratio increased after treatment with these herbicides. The lower concentrations tested produced a higher value of this coefficient. Depending on concentration both herbicides caused disturbances in respiration of needles of seedlings treated during bud formation. Stimulation of respiration by both herbicides in the newly formed needles of seedlings treated before bud development was observed.

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