EXPERIMENTAL FIGURE 20-44 An in vitro assay was used to identify molecules required for adherence of pollen tubes to the stylar ECM. In this assay, ECM collected from lily styles (SE) or an artificial ECM was dried on nitrocellulose membranes (NC). Pollen tubes containing sperm were then added, and their binding to the dried ECM was assessed. In this scanning electron micrograph, the tips of pollen tubes (arrows) can be seen binding to dried stylar ECM. This type of assay has shown that pollen adherence depends on stigma/stylar cysteine-rich adhesin (SCA) and a pectin that binds to SCA.

[Republished with permission of Springer, from Guang Yuh, J., et al., “Adhesion of lily pollen tubes on an artificial matrix,” Sex. Plant Reprod., 1997, 10:3, pp. 173–180.]