SELF-POLLINATION SHORTENS FLOWER LIFE-SPAN IN PORTULACA-UMBRATICOLA HBK (PORTULACACEAE)

I compared median Lifespan of exogenously unpollinated, hand self-, and hand cross-pollinated flowers of partially autogamous Portulaca umbraticola. Self-pollination consistently shortened flower lifespan in comparison with either cross-pollination or absence of hand-pollination. Median flower lifespan of cross-pollinated flowers did not differ from the median lifespan of unpollinated flowers. Seed set was greatly increased following hand-pollination but did not show significant differences between self- and cross-pollination treatments. Nevertheless, early self-pollination in natural populations of this species could lead to pollen limitation, a decrease in opportunities for outcrossing, and/or a decrease in pollen export by causing premature flower senescence of already short-lived flowers.