followed in pure HEMA and embedding in the same
resin, in a Teflon holder until reaching polymerization (Gerrits and
Smid, 1983). Sections of 5 m thickness were made using a RM2245
rotary microtome (Leica®). Toluidine blue O in 0.05% sodium benzoate
buffer, pH 4.4 was used for staining (Feder and O’Brien, 1968).
Permanent slides were deposited in the collection at the Structural
Botany Laboratory of the Biology Department, UFSM. Observations
and photomicrographs in bright field and polarized light were performed
using a DM 2000 microscope (Leica®) with a DFC 295 image
capture system (Leica®).