%0 Journal Article
%T Fluoride Exposure Compromises Gas Exchange of Plants
%A Geisa Lima Mesquita
%A Eduardo Caruso Machado
%A Ricardo Machado
%A Heitor Cantarella
%A Dirceu Mattos Jr.
%J American Journal of Plant Sciences
%P 16-20
%@ 2158-2750
%D 2013
%I Scientific Research Publishing
%R 10.4236/ajps.2013.412A3003
%X <p class=\"MsoNormal\">
	<span lang=\"EN-US\"><span style=\"font-family:Verdana;\">Fluorine (F</span><sup><span style=\"font-family:Verdana;\">-</span></sup><span style=\"font-family:Verdana;\">) stands out for its phytotoxic potential, because it accumulates in plants, changes enzymes activity, reduces chlorophyll content and, consequently, affects growth and yield of crop plants. An experiment was conducted to evaluate the effects of F</span><sup><span style=\"font-family:Verdana;\">-</span></sup><span style=\"font-family:Verdana;\"> on leaf gas exchange in coffee and sweet orange plants, compared to sensitive (gladiolus) and tolerant (ryegrass) reference species. Plants grown in pots were exposed to F</span><sup><span style=\"font-family:Verdana;\">-</span></sup><span style=\"font-family:Verdana;\"> in a semi-open mist chamber. The experimental design was completely randomized with treatments defined by the combination of plant species and two intensities of exposure to atmospheric F, with nebulization of HF solutions (low = 0.065 mmol<span style=\"background-color:#ffffff;font-family:Verdana, Helvetica, Arial;white-space:normal;\">กค</span>m</span><sup><span style=\"font-family:Verdana;\">-3</span></sup><span style=\"font-family:Verdana;\"> and high = 0.260 mmol<span style=\"background-color:#ffffff;font-family:Verdana, Helvetica, Arial;white-space:normal;\">กค</span>m</span><sup><span style=\"font-family:Verdana;\">-3</span></sup><span style=\"font-family:Verdana;\">) in a mist chamber, as well as with non-exposed control samples. CO</span><sub><span style=\"font-family:Verdana;\">2</span></sub><span style=\"font-family:Verdana;\"> assimilation (</span><i><span style=\"font-family:Verdana;\">A</span></i><span style=\"font-family:Verdana;\">), transpiration (</span><i><span style=\"font-family:Verdana;\">E</span></i><span style=\"font-family:Verdana;\">), stomatal conductance (</span><i><span style=\"font-family:Verdana;\">g</span><sub><span style=\"font-family:Verdana;\">s</span></sub></i><span style=\"font-family:Verdana;\">) and chlorophyll fluorescence rates were measured after 27 days of treatment application. The leaf gas exchange variables in ryegrass and orange plants did not vary in response to the increase in atmospheric F, while an increase in </span><i><span style=\"font-family:Verdana;\">g</span><sub><span style=\"font-family:Verdana;\">s</span></sub></i><span style=\"font-family:Verdana;\"> and </span><i><span style=\"font-family:Verdana;\">E</span></i><span style=\"font-family:Verdana;\"> values was observed in gladiolus and coffee
%K Fluoride Pollution
%K Gas Exchange
%K Citrus
%K Coffee
%K Bioindicator Species
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=40833