Application of Growth Regulators in Aqueous Media and Organic Solvents to Seeds of Picea abies and Pinus sylvestris

Incubation with acetone and dichloromethane had little effect on the germination of different lots of Norway spruce seeds. This was not the case with Scots pine where almost half the seed lots tested were adversely affected by acetone and dichloromethane. The auxins indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) were applied to Scots pine seeds in acetone, dichloromethane and phosphate-citrate buffer. The uptake of the two compounds was most rapid from acetone. Although the uptake from dichloromethane was slower than from acetone it reached the same level after 6 h. Uptake of the growth regulators from buffer was significantly lower than from the organic solvents. The accumulation of IAA and IBA into the seeds from both acetone and dichloromethane was linear between 0.5 and 10 mM, and between 0.5 and 15 mM from buffer. IAA and IBA levels in infused seeds declined over a 5-day germination period, the former more rapidly than the latter. The metabolic activity of the IAA degradation system was as effective in seeds after immersion in the organic solvents as seeds immersed in buffer.