RESPONSES TO COLD OF CHILEAN WILD SOLANUM SPECIES

Changes in frost resistance, cold acclimation capacity, contents of total soluble carbohydrates, free proline, and polar lipids and their constituent fatty acids in response to cold were studied in genotypes of S. brevidens (CON 876, CON 870 and SPOO 4454) and S. tuberosum (CON 841) 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 resistance and altitudinal or latitudinal origin of the investigated genotypes were observed. With the exception of CON 870, where a decrease of the initial frost resistance was found after cold treatment, the other genotypes showed acclimation capacity. This capacity was associated with an increase in free proline and total soluble carbohydrates only in SPOO 4454. The acclimation capacity of CON 876 was associated with higher phospholipid and galactolipid contents, but not with an increase in linolenic (18:3) acid. Phospholipids decreased in the non-acclimated CON 870 during cold treatment. In this genotype, PC decreased and its 18:3 acid disappeared under cold treatment. CON 876 and CON 870 showed a higher unsaturation ratio of fatty acids of some lipid fractions when cold treated. These ratios were higher in the non-acclimated genotype (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. Genetic variability among the physiological and metabolic responses to cold of these genotypes are discussed.