Abstract: It was found that there were calcium phosphate crystals inMammillaria schumannii. The tubercles ofM. schumanniiwere observed using a scanning electron microscope and an X-ray energy spectrum. The results showed that the mineral crystals, contained the O, Ca, and P elements, which were calcium phosphate and mainly embedded in the cortical cell wall with sporadic distribution in the cells. The majority of their morphological features resemble bouquets dispersed in all directions or just one, and rarely, olive balls coated with membranes could be seen. After weak-light treatment inM. schumannii, it was found that the crystal density in tubercles decreased obviously, a little amount of calcium phosphate crystals gathered together, and the overall size also decreased significantly (P<0.001). The results here provided a better understanding of the morphological characteristics of plant calcium phosphate as well as their roles in plants.

Key words: biomineralization;Mammillaria schumannii, calcium phosphate, morphological feature microscopy, scanning electron microscopy