The Effect of Low Temperature upon Starch, Sucrose and Fructan Synthesis in Leaves

Measurements on plants in a temperature gradient tunnel show that diurnal accumulation of starch in illuminated leaves was greatly reduced at temperatures below 8 °C, whereas sucrose synthesis was less affected under similar conditions. High chilling sensitivity for leaf starch accumulation was observed in a number of chilling resistant temperate species. Enzymes of sucrose and fructan metabolism from mature leaves of Lolium temulentum were less strongly inhibited at low temperatures than enzymes involved in starch synthesis. These results are discussed in relation to carbon partitioning in species which grow and are metabolically active at chilling temperatures.