Abstract:

Seasonal differences in the water content of fourCodringtoniaspecies were investigated using specimens collected from the field. In addition, rate of water loss and expression of heat-shock protein 70 (Hsp70) were measured in a laboratory setting with sixCodringtoniaspecies subjected to a short-term heat shock. Using a phylogenetic framework, both the Hsp70 expression levels and the rate of water loss were inves tigated for their correlation with spatial and climatic variables. As indicated by the field-collected samples, during summer aestivation only C. helenaeexhibited a tendency for water loss. During the short-term heat shock the rate of water loss inC. helenaewas also significantly greater. No interspecific differences could be detected in the levels of Hsp70 in the species subjected to short-term heat shock. A singleCodringtoniaspecies seemed to maintain increased Hsp70 protein levels. In the species subjected to short-term heat shock, a positive relationship was found between Hsp70 levels and rate of water loss. On the other hand, the Hsp70 levels under normal conditions showed a negative correlation with altitude and mean summer precipitation of the sampling localities. Thus, species seem to adapt to harsher environmental conditions by maintaining higher levels of Hsp70.