Fig. 9.

Pollination induces synthesis and release of NaStEP into the N. alata stigmatic exudate. Total protein from exudate of unpollinated and pollinated stigmas of N. alata cv Breakthrough were sequentially extracted, separated by SDS–PAGE, and blotted to nitrocellulose for immunostaining with anti-NaStEP (top) or silver nitrate stained (bottom). Equal volumes (30 μl) were loaded in each lane. (a) Total protein from exudate of unpollinated stigmas at anthesis and at 48 h old. (b) Total proteins from exudate after 5, 12, and 24 h of self-pollination. (c) Total proteins from exudate after 5, 12, and 24 h of pollination with N. tabacum pollen. (d), (e), and (f) Densitometric analysis of NaStEP expression and its presence in the stigmatic exudate of N. alata before and after pollination with self- and N. tabacum pollen. L, low-salt wash; H, high-salt wash; T, proteins remaining in the stigma after washes.