STUDIA FORESTALIA SUECICA Ripening process in relation to tem- perature and sugar content in seeds of Scots pine (Pinus silvestris L.)

ODC 232.318: 174 Pinus silvestris +161.4 The investigation was performed on seeds of Scots pine (Pinus silvestris L.) from one and the same stand of trees in three consecutive years with samplings during I September-1 April. Germination capacities, relative germination rates and concomitant changes of carbohydrates during the actuul ripening period were studied. The end of the ripening process during September-October hay been discussed in relation t o frost temperatltres during the same period. It has been stressed that ztnfavo~trable temperatures during sen~i t ive phases of the ripening process can damage the seeds' further development, and jeopardize the well-known correlation between the mean temperatures for the months June-September and the ripeness. Quantitative changes of glucose, fructose, sucrose, ruffinose and stachyose were studied with gas-chromatography. For starch u colorimetric technique was used. T h e content of glucose and fructose evidently decreased with increasing ripeness during September-October. A concomitant new formation o f sucrose, raffinose and stachyose war observed. Starch was found in all ump le s , irrespective of the sampling dates, with a minimum content in September und with a more irregztlur but similar trend o f new formation. T o correlate the degree of r ipene~s a\ exprened in the germinability with yome coincidental content of one of the carbohydrates has 17ot been possible. Ms. received 1973-04-19