Progress 01/07/08 to 12/31/08
Outputs Progress Report Objectives (from AD-416) Evaluate quality of seed accessions collected on NPS lands and recommend storage procedures that will maximize seed longevity. Approach (from AD-416) Recent work provides new potential assays that quickly and noninvasively identify seeds that may be sensitive to low temperature storage. A technique using differential scanning calorimetry (DSC) measures thermal properties of storage lipids (triacylglycerol: TAG) quickly and non- invasively using < 10 mg of seeds and reveals a likely mechanism for the faster degradation. Another technique measures water affinity in seeds at different storage temperatures and likely reveals risks of inadvertent overdrying. Using these techniques as assays to identify species that are at risk allows collections managers to select the most appropriate storage conditions to maximize seed longevity (i.e., appropriate drying conditions and -18 versus cryogenic storage). Other emerging DSC techniques show promise in non-invasively detecting loss of viability during storage for NPS-CPC accessions regardless of their storage physiology, obviating the need to deplete seeds from the core collection periodically for germination monitoring. Significant Activities that Support Special Target Populations About 75% (109 accessions of 145) species-park units from the CPC-NPS agreement have been collected. About 80% of NPS acquisitions (86 of 109), representing 85 species from 44 national parks, have been sent to NCGRP for analysis and long term preservation. NCGRP received germplasm and evaluated different methods to log in accession information and evaluate quality of the seeds. Seed quality was evaluated in terms of percent of seeds with visible embryos, evidence of predation or fungal contamination, seed mass, and moisture level upon receipt at NCGRP. NCGRP also applied new techniques that evaluate thermal behavior of lipids. These methods are nondestructive and appear to flag materials inappropriate for -18oC storage and indicate sample deterioration during storage. When sufficient seed were available, NCGRP performed a germination assay which will be used to validate predictions of seed storage behavior and longevity made using noninvasive measurements. Time to germination was recorded and will be evaluated with storage duration as a measurement of after-ripening and seed deterioration. Seed fill was tested for some accessions by dissecting seeds (see attached figures). Assessments of seed fill were routinely performed on accessions containing larger seeds with low % germination, large amounts of associated chaff or evidence of predation. Interestingly, seed fill varied among maternal lines in some accessions. X-ray assessments are a new capability at NCGRP and are recommended for a subset of cleaned seeds collected from wild populations. The unique partnership between NPS, CPC and NCGRP represents new initiatives to capture the full value of banked germplasm as our environment faces rapid changes and imperiled populations suffer progressively dwindling population size.
Impacts (N/A)
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