Jack pine (Pinus banksiana Lamb.) pollen effects on jack pine and black spruce (Picea mariana (P. Mill.) B.S.P.) seed germination and seedling growth
Bakke, Olaf Andreas
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Effects of jack pine pollen on jack Pine and black spruce seed germination and jack pine seedling growth were investigated. Generally, 'in vitro ' speed of seed germination and radicle growth of both species were negatively affected by normal pollen levels (average annual jack pine pollen rain, i.e. 8.5 kg/ha.yr). Black spruce weds under sterilized 'in vitro ' conditions germinated faster and produced longer hypocotyls when provided with jack pine pollen amounts equal to the annual rain. On mineral soil under controlled conditions, seed germination of both species was unaffected by jack pine pollen additions at 10x the annual jack pine pollen rain. Additions at 50x and 100x the annual jack pine pollen rain significantly reduced radicle length and resulted in up to 65% of germlings with infested (e.g. pathogenic fungi) radicles. Pollen application, of levels equal to annual pollen rain, to potted jack pine seedlings under greenhouse conditions increased seedling biomass by up to 12% at the end of the first growing season. In mineral soil field sites of west-central Manitoba, biomass and growth of jack pine seedlings were positively affected by supplements of increasing pollen levels up to 100x annual pollen rain. Possible nutritional and. hormonal effects of pollen on seed germination and seedling growth are discussed and topics for future research are identified.