Figure 4

Sections from different samples of the aerial parts of pea (a,e,i,l,o,r), sunflower (b,f,j,m,p,s), tomato (c,g,k,n) and wheat (d,h,q,t). a) Detail of the crown of pea after 24 h of exposure to bioferrofluid. b) Idem in sunflower. c) Idem in tomato. d) Crown of wheat after 24 h of exposure, showing an intense accumulation of bioferrofluid in tissues. e) Detail of the crown of pea after 48 h of exposure to bioferrofluid. f) Idem in sunflower. g) Idem in tomato. h) Detail of a longitudinal section in wheat after 48 h of exposure to bioferrofluid. i) Detail of a cross section of the first internode of pea after 24 h of exposure to bioferrofluid. j) Idem in sunflower. k) Idem in tomato. l) Detail of a cross section of the first internode of pea after 48 h of exposure to bioferrofluid. m) Idem in sunflower. n) Idem in tomato. o) Detail of a cross section of the second internode of pea after 24 h of exposure to bioferrofluid. p) Idem in sunflower. q) Detail of a longitudinal section of the second internode in wheat after 24 h of exposure to bioferrofluid. r) Detail of a cross section of the second internode of pea after 48 h of exposure to bioferrofluid. s) Idem in sunflower. t) Detail of a longitudinal section of the second internode in wheat after 48 h of exposure to bioferrofluid. Scale bars represent 100 μm, except in g), q) and t) whereas it represents 50 μm. Arrows indicate accumulation of nanoparticles in vascular tissues in a-c), f), i-t), and in cortical cells in e), g), h). Arrowheads indicate accumulation of nanoparticles in cortical cells in a), l), r), and in trichomes in q). Asterisks (*) indicate localization of vascular bundles.