Physiological adaptation to subantarctic climate by the Kerguelen cabbage, Pringlea antiscorbutica R. Br.

摘要

The Kerguelen cabbage,Pringlea antiscorbutica, is an endemic species restricted to some Subantarctic Islands, Up to now, all long term acclimatation assays of Kerguelen cabbage in the temperate zones remained unsuccessful. In the field, thePringlealeaf relative water content (RWC) never decreased below 83. At the same time the leaf diffusion resistance (LDR) remained low since the water flux was not limited in the plant as in these islands the soil water content is permanently high. Severe water deprivation was necessary to induce stomatal closure with excised leaves. In parallelin vitroexperiments, irreversible damage to photosynthesis and respiration were observed in leaf slices under osmotic stress. These results sustain the hypothesis that Kerguelen cabbage can not support water deprivation and is probably specifically adapted to the subantarctic climate.