Cleared-pistil and thick-sectioning techniques for detecting aposporous apomixis in grasses

Two techniques were evaluated for detecting sexual and aposporous embryo sacs in an apomictic grass. Pistils of Cenchrus ciliaris L. were fixed in formalin – acetic acid – alcohol (FAA), cleared in methyl salicylate, and examined in toto by interference contrast microscopy. The same pistils were then embedded in plastic, sectioned, and studied by conventional microscopy. The two methods yielded identical interpretations of embryo sac morphology. The cleared-pistil technique was simple and required about 1/10 the time of the sectioning method.