RESPONSES TO COLD OF CHILEAN WILD SOLANUM SPECIES

Changes in frost resistance, cold acclimation capacity, contents of to tal soluble carbohydrates, free proline, and polar lipids and their co nstituent fatty acids in response to cold were studied in genotypes of S. brevidens (CON 876, CON 870 and SPOO 4454) and S. tuberosum (CON 8 41) with different geographical distribution. Among the cold-untreated genotypes the least frost resistance was found in CON 841 (LT(50) = - 1.2 degrees C) and the greatest in CON 870 and CON 876 (LT(50) around -4 degrees C). No significant direct correlations between frost resist ance and altitudinal or latitudinal origin of the investigated genotyp es were observed. With the exception of CON 870, where a decrease of t he initial frost resistance was found after cold treatment, the other genotypes showed acclimation capacity. This capacity was associated wi th an increase in free proline and total soluble carbohydrates only in SPOO 4454. The acclimation capacity of CON 876 was associated with hi gher phospholipid and galactolipid contents, but not with an increase in linolenic (18:3) acid. Phospholipids decreased in the non-acclimate d CON 870 during cold treatment. In this genotype, PC decreased and it s 18:3 acid disappeared under cold treatment. CON 876 and CON 870 show ed a higher unsaturation ratio of fatty acids of some lipid fractions when cold treated. These ratios were higher in the non-acclimated geno type (CON 870), due to the increase in the 18:3 acid proportions. Thus , our results have not been able to provide a mechanistic insight into the cold acclimation processes of the Chilean wild Solanum species. G enetic variability among the physiological and metabolic responses to cold of these genotypes are discussed.