Martínez-Peralta C., Mandujano M. C., Pollen Limitation in a Rare Cactus with Synchronous Mass Flowering, Haseltonia, 2016, 22:2-8, doi: 10.2985/026.022.0102
The 2007 experiment on Ariocarpus kotschoubeyanus from Tula compares natural pollination with added mixed pollen from ten donors. After some flowers were damaged, samples contained 17 and 19 flowers. Additional pollen increased mean seeds per fruit and seed production relative to mean ovule number. The proportion of fruiting flowers remained similar. The paper also covers flower lifespan and nectar measurements.