Hernández-Cruz R., Barrón-Pacheco F., Sánchez D., Arias S., Vázquez-Santana S., Functional Dioecy in Echinocereus: Ontogenetic Patterns, Programmed Cell Death, and Evolutionary Significance, International Journal of Plant Sciences, 2018, 179(4):257-274, doi: 10.1086/697072
A comparative study of flower and seed development in five Echinocereus taxa. Controlled pollination, histology, electron microscopy and TUNEL assays revealed different timing of the loss of male and female function in the studied dioecious taxa. The authors discuss the association of sterility with programmed cell death and propose a heterochronic interpretation.