Pelecyphora vivipara

Name and distribution

Pelecyphora vivipara is an accepted species in POWO with a natural range from southern Canada to northern Mexico. The name in this genus was published in 2022 (formerly Escobaria vivipara). POWO includes the former var. arizonica and var. neomexicana within the accepted species. [2-WWW]

Chemia badanych nasion

Chen and colleagues described a high content of typical G/S lignin in seeds of material identified as Escobaria vivipara, with the designations arizonica and neomexicana (now Pelecyphora vivipara). G and S denote guaiacyl and syringyl units. The result concerns these seed batches, distinguished by the authors using former infraspecific names. [Chen et al. 2013, pp. 206–208, material list and description of fig. S2]

Microscopic examination of arizonica material served for comparison with seeds containing 5H lignin or no detectable lignin. The intensity of coat autofluorescence did not directly reflect the amount of this polymer. The chemical type of the walls was identified by combining degradation methods, NMR and microscopy. [Chen et al. 2013, pp. 207–209, Fig. 5]

Freezing of material historically called deserti

In 1981, Nobel studied Pelecyphora vivipara (Coryphantha vivipara var. deserti in the publication) from Mercury Valley in Nevada. Plants of the World Online places this historical variety in the synonymy of P. vivipara. Its origin at a single site remains relevant when assessing the freezing results. [Nobel 1981, pp. 194–195. POWO, 11 October 2026] [2-WWW]

In laboratory exposures over nine hours at night, five of five plants survived at −12°C, three of five at −15°C and none of five at −20°C. Survival was defined by the return of a positive nocturnal CO₂ balance within two months. Plants underwent successive trials after positive gas exchange had recovered. In survivors of −15°C, no positive CO₂ uptake was detected for the first ten nights, and after two months activity was still about half its initial value. [Nobel 1981, p. 195–196, ryc. 1–2]

Ice, cell dehydration and acclimation

During slow cooling, the stem remained supercooled to about −6°C, after which heat release indicated ice formation. The author interpreted this as freezing of water outside the protoplasts. Cells lost water and shrank as temperature fell. Observations of vital staining and plasmolysis linked survival to tolerance of this dehydration. The measured osmotic potential of the sap alone lowered the freezing temperature by only about 0.9°C. [Nobel 1981, p. 196–198, ryc. 3–4]

Gradually lowering the temperature at which plants were kept from 30 to −10°C in weekly steps shifted the temperature causing a 50% decline in the cells' capacity for vital staining from about −10 to −17°C. Acclimation was assessed at cellular level through a change in the selected viability indicator. The result applies to laboratory conditions with a specified exposure duration and prior temperature at which the plants were kept. [Nobel 1981, pp. 196–198]

Related articles

Materials from the author's archive

The species also appears in Konrad Szychowski's private material archive. [Kaktologia 2009b, file p. 9] [Neciu b.d., file p. 1] [Sukulenty b.d.b, file p. 3] [Kaktusy i Inne 2005a, file p. 7] [Modrakowski 2005, file p. 44] [Anonim b.d.r, file p. 99]