EVALUATION OF MALATE-DEHYDROGENASE ACTIVI TY IN DETERIORATED SUNFLOWER SEEDS

Malate dehydrogenase (MDH) activity in sunflower (Helianthus annuus L. cv. Peredovik) seeds stored at 65 degrees C and 90 degrees C for 1, 3 , 5, 7, and 14 days was evaluated. This study was design to discern th e usefulness of this viability test for deteriorated seeds. Difference s in the resistance to the heat storage were detected between treatmen ts as reflected by changes in the evolution of MDH activity. A decreas e of MDH activity in both soluble and mitochondrial fractions was obse rved, which was more evident in seeds stored at high temperature. Thes e differences are poorly correlated to viability as determined by tetr azolium staining, and should be related to integrity of cellular membr anes as evidenced by differential MDH activity in soluble and mitochon drial fractions.