3.2.3. Evaluating stigmatic receptivity
Pollination success is dependent on stigmatic receptivity since only insect visits to receptive stigmas can be considered as effective pollination visits. A receptive stigma allows pollen grain adhesion that can be followed by pollen hydration and germination. Stigmatic receptivity can be evaluated directly by studying conspecific pollen germination (see 3.2.4.) or indirectly by studying activity of enzymes (Dafni et al., 2005) such as esterase (with a benzidine solution) or peroxidase (with alpha-naphthyl acetate) or the presence of exudates in wet stigmas stained with Sudan black or auramine O (Kearns and Inouye, 1993). Herein, we discuss determining stigmatic receptivity only by studying conspecific pollen germination.