Activity of sucrose synthase, soluble acid invertase and fumarase in germinating seeds of Scots pine (Pinus sylvestris L.) of different quality

Two sub-lots were selected from a seed lot of Scots pine (Pinus sylvestris L.) according to the size of embryos based on X-ray image. The germination capacity (GC) and mean germination time (MGT) of these two sub-lots was 91. 5% and 6.6 days and 49.5% and 8.5 days. Each sub-lot was subjected to primi ng at 30% moisture content plus GA,,, and 6-benzylaminopurine. The activiti es of sucrose synthase, soluble acid invertase acid fumarase were determine d and correlated with developmental degree and seed quality. Priming decrea sed MGT by ca. 3 days. GA(4/7), 10(-7) M, increased the GC of poorly develo ped seeds from 49.5% to 57.4%. The sucrose synthase activity of poorly deve loped seeds was twice as high as that of well-developed seeds, indicating t hat the poorly developed seeds were interrupted in their development during maturation at a time when sucrose was still being transported into the see ds. Sucrose synthase activity is therefore a potential indicator of the dev elopmental degree (viability) of the seed. The activity of fumarase increas ed during priming, indicating that one important effect of the pre-treatmen t is an increased capacity for the mitochondrial degradation of stored lipi ds in the embryo and megagametophyte. Fumarase activity in the seed can the refore serve as an indicator of seed vigour.