Ripening process in relation to temperature and sugar content in seeds of Scots pine (Pinus silvestris L.)
Kardell, Lars; Bobeck, Stina; Nyman, Bengt
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 1 September-1 April. Germination capacities, relative germination rates and concomitant changes of carbohydrates during the actual ripening period were studied. The end of the ripening process during September-October has been discussed in relation to frost temperatures during the same period. It has been stressed that unfavorable temperatures during sensitive 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, raffinose and stachyose were studied with gas-chromatography. For starch a colorimetric technique was used. The content of glucose and fructose evidently decreased with increasing ripeness during September-October. A concomitant new formation of sucrose, raffinose and stachyose was observed. Starch was found in all samples, irrespective of the sampling dates, with a minimum content in September and with a more irregular but similar trend of new formation. To correlate the degree of ripeness expressed in the germinability with some coincidental content of one of the carbohydrates has not been possible.
seed quality; Pinus silvestris; ripening process; sugar content
Studia Forestalia Suecica
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