Impact of flumioxazin herbicide on growth and carbohydrate physiology in Vitis vinifera L.

The impact of flumioxazin herbicide on in vitro-grown grapevine (Vitis vinifera L. cv. Chardonnay) was investigated. The herbicide treatments (1, 10 or 100 muM flumioxazin in MM medium) had a negative impact on photosynthesis, as revealed by a reduction in foliar chlorophyll and carotenoid contents, gas exchanges and alteration in plastid structure and, consequently, resulted in a strong inhibition of plantlet growth. Surprisingly, soluble sugars and starch accumulated in all organs, suggesting a stimulation of sugar uptake from the medium. Moreover, photosynthetic activity and starch content partially recovered within 3 weeks of treatment at the weakest herbicide concentration. These results provide new insights into the physiological responses of nontarget crops to flurnioxazin, showing that flumioxazin is active in photosynthetic tissues of the non-target grapevine via root uptake, which is contrary to what is mentioned in the literature, and that the in vitro-grown plantlet is a good model for investigating the physiological effects of pesticides on crop species.