Cylindropuntia bigelovii

Plant organisation

Cylindrical segments are densely covered with spines bearing pale sheaths, giving the plant its characteristic compact outline. The species is associated with desert areas of southwestern North America. Terminal segments can detach easily from the mother plant and provide vegetative propagation material. The older name used in physiological experiments is Opuntia bigelovii. [Mylo et al. 2022] [Nobel 1983] [2-WWW]

A junction that breaks

In a tensile experiment on segment junctions, median maximum force was 14.4 N. In the younger and older Opuntia ficus-indica junctions compared, it was 51.2 and 153 N, respectively. After accounting for cross-sectional area, tensile strength was also lower in the cholla examined. Results describe the experimental material, in which C. bigelovii segments came from one plant. [Mylo et al. 2022]

The fracture surface often formed a cone and matching depression. Some vascular tissue and parenchyma were torn from the neighbouring segment. The geometry of the constriction and differences in tissue stiffness influence stress concentration and crack propagation. [Mylo et al. 2022] [Striet et al. 2025]

Wound closure

After controlled incision of external tissues, the wound edge gradually curled inward and the surface layer died. A barrier rich in lipophilic substances developed in the first days, followed by lignification changes and wound periderm. After 31 days, both plants studied, cholla and opuntia, had new protective tissue. [Mylo et al. 2020]

In C. bigelovii, partial recovery of some stiffness parameters was recorded after wounding. Mechanical measures changed differently, so rebuilding the surface barrier and recovering load-bearing capacity are separate stages in describing regeneration. [Mylo et al. 2020]

Spines, light and metabolism

Nobel compared nocturnal acidity increases at different daily light doses, retaining or removing spines for the experiment. After removal, the tissue examined reached 90% of maximum response at lower radiation incident on the plant. Spines changed the number of photons reaching the green surface, explaining part of the difference in curve shape. [Nobel 1983]

Cloning and variation

In the 2025 genetic comparison of six chollas, C. bigelovii represented a strongly clonal taxon. Material was assigned to a triploid population from earlier site data. Repeated occurrence of the same genotype was considered alongside SNP markers and the different reproductive systems of the other species. [Ramadoss et al. 2025]