Follow-up of fluorine pollution effect on grapevine
Abstract
Effects of atmospheric pollution on three local grapevines, Asli, Jerbi and Tounsi, growing in the vicinity of a phosphate fertiliser factory, consist of an exhibition of characteristic necrosis on leaves and fruits. Analysis of necrotic leaf areas allowed us to distribute local vines into sensitivity classes. The follow-up, in function of time and space, of stomatal conductance and leaf fluoride content during the different seasons allowed us to reveal some offensive strategies allowing these vines to escape from pollutants toxicity and maintaining its vitality. Therefore, giving that fluorine is strange to its metabolism, grapevine tends to accumulate it, thanks to an external concentration mechanism, in the tips and leaf margins. Necrotic areas are delimited by a narrow brown border line. Thus, allowing the plant not only to avoid F- toxicity, but also to keep a big assimilation surface. In addition, possibilities as F- excluding, F- vacuol partitioning, temporary closing of stoma, F- trapping as CaF2, SiF4 are also to be considered.
By another way, our results seem to show that full mature grapevine leaves may constitute an efficient tool to assess fluorine pollution impact. Berries contamination seems to be affected directly by the factory smoke, there is no endogenous supply. Likewise, by its characteristic necrosis in the leaf boundaries, grapevine may be considered as a bioindicator variety of fluorine pollution which can be used in mapping polluted areas.