Refinement of a clearing protocol to study crassinucellate ovules of the sugar beet (Beta vulgaris L., Amaranthaceae)

Table 1 Clearing effects of methyl salicylate on exemplary tenuinucellate and crassinucellate ovules in pre- and post-fertilization stages using the standard^a procedure or its modified^b version (n ≥ 15)

Ovule type	Species	Clearing procedure	Clearing effect^c
Tenuinucellate	Arabidopsis thaliana ^d	Standard	+
Tenuinucellate	Arabidopsis thaliana ^d	Modified	++
Crassinucellate	Biscutella laevigata	Standard	+
	Armeria maritima	Standard	+
	Viola banksii	Standard	+
	Beta vulgaris	Standard	−
		Modified	−

^aThe standard procedure: absolute ethanol : methyl salicylate, in proportions of 3:1, 1:1, 1:3, 0:1 (1.5 h each change)
^bThe modified procedure: as the standard, except the step of clearing in pure methyl salicylate, which was prolonged from 24 h to 4 weeks
^c(++) very well cleared ovules; (+) ovules cleared at an acceptable level; (−) ovules cleared at an unsatisfactory level
^dThe whole ovaries were cleared to prevent the material loss during its preparing process

ISSN: 1746-4811