Pollen viability and longevity in Juniperus taxa native to Slovakia

Abstract

Abstract Pollen viability, its dispersion ability and longevity during a deep-freezer storage was studied in three Juniperus taxa naturally distributed in Slovakia. All these characteristics of pollen are closely related to the pollination and/or fertilization success of the junipers in nature. Pollen viability varied considerably between the three populations of J. communis and one population of each, J. sibirica and J. communis var. intermedia. Pollen germination rate ranged between 40,75% and 75,06%, pollen tube length between 30,32 µm and 40,41 µm. A clear tendency has appeared indicating higher germination rate of J. communis pollen from lower altitudes and reduced germination of J. sibirica and J. communis var. intermedia pollen from higher altitudes. Dispersion potential of the J. communis pollen during its shedding seems to be relatively low. In 2021, the density of pollen cloud was diluted of 68,1% at the 4 m distance from the test shrub. In 2022, this figure was represented by the 52,1% reduction at the 17 m distance from the pollen source. A deep-freezer storage of juniper pollen in double-walled polyethylene bag with silica gel was not efficient enough as indicated by the drop of pollen germination rate of 31,2% in J. communis and of 79,4% in J. sibirica during a 1-year storage period at -81ºC.