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Low‐Temperature Tolerance and Cold Hardening of Cacti
Author(s) -
Nobel Park S.
Publication year - 1982
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1940106
Subject(s) - cold tolerance , ecology , cold hardening , hardening (computing) , freezing tolerance , biology , botany , materials science , nanotechnology , biochemistry , layer (electronics) , gene
Reduced uptake by the chlorenchyma cells of cacti of a stain (neutral red) was used as an indicator of low—temperature damage resulting from cooling stems in the laboratory. Necrosis set in a few degrees below the temperature at which the fraction of cells accumulating stain was reduced by 50%, Coryphantha vivipara, Opuntia polyacantha, and Pediocactus simpsonii, which range to over 3000 m altitude in southern Wyoming, were quite cold tolerant (50% inhibition of staining occurred from —17° to —20°C)m while O. bigelovii and O. ramosissima, which are restricted to much warmer habitats, were not very cold tolerant (50% inhibition from —4° to —7°). Relationship among tissue cold sensitivity, morphological features which protect the stems from low temperatures, and the occurrence of species in progressively colder regions were investigated. Differences in tissue cold sensitivity accounted for the °600 m higher elevational limit of Coryphantha vivipara var. rosea compared to the morphologically similar var. deserti in southern Nevada. In contrast, morphological differences alone could adequately explain the relative northern limits of the columnar cacti Carnegiea gigantea vs. Stenocereus gummosus and the barrel cacti Ferocactus acanthodes vs. F. wislizenii in the southwestern United States, as previously indicated using a computer model. Differences in both morphology and tissue cold sensitivity apparently influenced the relative northern ranges of Lophocereus schottii with respect to the other columnar cacti and F. covillei with respect to the other barrel cacti, as well as the relative elevational range of Denmoza rhodacantha with respect to Trichocereus candicans in northcentral Argentina. Cold hardening in response to decreasing day/night air temperatures was observed for 10 species. A decrease from 50°/40° to 10°/0° lowered by 4° the temperature at which the fraction of the chloirenchyma cells taking up stain was reduced 50% for both D. rhodacantha and T. candicans, with a half—time for the shift of °3 d. The tolerance of subzero temperatures and the ability to cold harden allow cacti to range into regions with considerable wintertime freezing.