EFFECTS OF ASCOCHYTA BLIGHT CAUSED BY MYCOSPHAERELLA-PINODES ON THE TRANSLOCATION OF CARBOHYDRATES AND NITROGENOUS COMPOUNDS FROM THE LEAF AND HULL TO THE SEED OF DRIED-PEA

The effects of Ascochyta blight (caused by Mycosphaerella pinodes) on changes in dry weight and in water, carbohydrate, nitrogen and free am ino acid contents were studied in the leaf, the hull and the seeds on the second fructifer node of pea (Pisum sativum). Pea plants were grow n in a glasshouse and inoculated with various concentrations of conidi a at the beginning of seed filling, with uninoculated plants as contro ls. Disease induced a premature water loss of hulls and leaves, accele rated seed desiccation and reduced seed weight. Biochemical analyses r evealed a decline in the carbohydrate content and a lower nitrogen rem obilization in diseased leaves and hulls. Thus, Ascochyta blight alter s carbohydrate metabolism, protein remobilization and free amino acid translocation from these organs. Disease also reduced carbohydrate and nitrogen content in seeds and, in case of high disease severity, the carbohydrate/nitrogen ratio in the seeds was also affected (seed prote in concentration increased and starch concentration decreased).