Fizjologiczne reakcje na N–NO3 i N–NH4 odpornych i wrażliwych na triazyny roślin przymiotna kanadyjskiego (Erigeron canadensis L.) [Physiological responses to N–NO3 and N–NH4 of triazine resistant and susceptible plants of horseweed (Erigeron canadensis L.)]

Ryszard Stanek

Abstract


Triazine resistant and susceptible biotypes of horseweed (Erigeron canadensis L.) were grown under controlled conditions in nutrient solution with NH4 or NO3 ions as nitrogen source. Indicators such as: dry matter, CO2 assimilation, chloroplasts activity, dark respiration and the content of K, Ca, Mg in the above ground parts displayed lower levels when plants were fed with NH4 than with NO ions. Reduction of these indicators was stronger for the triazine susceptible plants which grew better than their resistant counterparts when fed with N–NO3. The triazine resistant plants grown with N–NH4 contained more protein-N and K than the susceptible ones. Chloroplasts of the resistant plants were also less sensitive to NH4CL treatment. It is concluded that the resistant plants appear to be more tolerant to NH4 ions as compared with their susceptible counterparts. For this reason application of ammonium forms of nitrogen fertilization in horticultural practice could favour spreading of triazine resistant horseweed.

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