Effects of norflurazon on СО2 fixation and Rubisco activity in some C3 and C4 plants under different light intensity

Abstract

Norflurazon (NF) is a herbicide that is known to inhibit carotenoid biosynthesis, destroy chlorophylls, desintefrate chloroplasts, and ruin chloroplast ribosome. In this study, we clarify how light intensity modulates effects of NF on 2 fixation and activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in some C 3 and C4 plants. We investigate effects of NF on maize, barley, triticale, and radish under low light intensity (0.12 and 0.4 W/m 2 ), and on maize, wheat, bean, and radish under high light intensity (100 W/m 2 ). We show that the effects are modulated by light intensity and species peculiarities. Specifically, C3 plants, with no mechanism for CO2 recycling, loose carbon compounds easier compared to C4 plants, resulting in earlier manifestation of photodestruction under NF treat ment. Besides, we show that Rubisco activity increases as far as its content decreases. K e y w o r d s : CO2 fixation, Rubisco activity, light intensity, norflurazon, C3 plants, C4 plants, carotenoids, chlorophylls .., .., .. CO 2 Rubisco C3 C4 . () , , . CO2 Rubisco C 3 - C4- . , , (0,12 0,4 / 2 ), , , - (100 / 2 ) , . , C 3 -, CO2, , . , Rubisco .