Comparison of 5 Pollen Storage Protocols for Subtropical Pine Species
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Date
2005-11-25
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Abstract
Storage of pine pollen for breeding and conservation purposes is essential to conserve valuable genetic material over time. Customized storage protocols are often necessary to address differing strategies and program goals for specific pine species. Subtropical pine pollen has been and will be important for forestry programs around the world, and the evaluation of pollen storage protocols for these species permits the determination of successful strategies to maintain viability over time. Germination of pollen grains using in vitro agar gel methodology has been shown to successfully predict in vivo germination of pollen tubes. Five methods commonly used for temperate pine pollen storage were evaluated for their efficacy for maintaining temperate (P. taeda, P. radiata) and subtropical species (Pinus tecunumanii, P. oocarpa, P. maximinoi) pollen after 6 months.
For best results, cryopreservation at -196°C should be used for subtropical pine pollen storage if available. When reliable resources for cryopreservation are limited, direct freezing at -20°C is recommended. Like the P. taeda and P. radiata pollen evaluated in this study, subtropical pine pollen exhibited increased in vitro germination rates when exposed to the lower temperatures evaluated after 6 months in storage. Temperate species pollen storage protocols evaluated in this study were used successfully for subtropical and tropical pine species.
The 3 subtropical pine species' pollen assessed diverged from temperate pollen behavior when only prestored pollen is considered. Cryogenic and direct freezing storage methods yielded higher in vitro germination rates for subtropical species than temperate species (P. taeda and P. radiata). Vacuum drying/freezing and refrigeration, however, yielded higher in vitro germination rates for temperate species. Additional research into the physiology of these differences and the correlations with evolutionary phylogeny information is recommended to determine the cause of these differences.
Key words: subtropical pines, pollen storage, pollen cryopreservation, in vitro germination
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Keywords
in vitro germination, pollen cryopreservation, subtropical pines, pollen storage
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Degree
MS
Discipline
Forestry
