An improvement to the topographic tetrazolium testing of Scots pine (Pinussylvestris L.) seeds

Fifteen different variants of the topographic tetrazolium (TZ) testing were examined in order to find a quick and reliable method for testing the viab ility of Scots Dine seeds. The variants of the conventional TZ-method diffe red in the area of cutting, premoistening before or after cutting and durat ion of staining. The accelerated infiltration of the staining solution into seed tissues under sub-atmospheric pressure was also tested. Good results were attained with the conventional method when seeds were cut at both ends before staining in a 1% 2,3,5-triphenyl tetrazolium chloride solution at 3 0 degrees C for 24 hours. In the vacuum method, dry seeds were cut at basal and epical ends before de-gassing in a vacuum desiccator three times for 1 0 minutes at 23,6 kPa in a 1% tetrazolium solution. The best results were o btained when seeds were completely soaked into stain while in the vacuum. S taining was completed by incubating seeds in the staining solution at 30 de grees C for four hours. The best vacuum and traditional TZ-methods gave sim ilar results for the same seed lot of Scots pine. The vacuum TZ-staining ta kes only 4 h 30 min, while the most efficient traditional method lakes 42 h (time for cutting and evaluation of seeds excluded).