Differential cold tolerance, starch, sugar, protein, and lipid of yellow and purple nutsedge tubers.
Märksõnad
Abstraktne
From measurements of viability after exposure of tubers to natural overwintering in the soil and 6 weeks exposure at 2 C, species cold tolerance of the tubers was ranked in decreasing order: yellow nutsedge ;I' (Cyperus esculentus L.), an ecotype originating in Illinois; yellow nutsedge ;G', an ecotype originating in Georgia; and purple nutsedge (Cyperus rotundus L.). The ratios of unsaturated-saturated fatty acids in tuber triglycerides, tuber polar lipids, and leaf polar lipids followed the same order as the cold tolerance rankings, with the most cold-hardy species having the highest ratios. Lipid content was less than 1% of dry weight in purple nutsedge tubers, but was from 5 to 7% in both yellow nutsedge tubers. Starch, sugar, and lipid contents increased significantly in the hardy yellow nutsedge ;I' tubers during a 6-week exposure to 2 C, but did not change in the susceptible purple nutsedge tubers; only sugar increased in yellow nutsedge ;G' tubers after this treatment. Protein content was not altered by the 2 C treatment in any of the tubers. Apparently, several factors involving starch, sugar, lipids, and fatty acids are related to the differences in tolerance to cold in these species.