Longevity of seeds

8b similarly nitrogen requirements do not appear to

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Unformatted text preview: carbon allocated to seed production also does not appear to correlate with seed longevity in a small, but representative, subset of the species from the NPGS collection (Fig. 8B). Similarly, nitrogen requirements do not appear to influence seed longevity (Fig. 8C), although this statistic may be meaningless under cultivation scenarios where nitrogen is not a limiting resource. 18 C. Walters et al. Figure 7. The relationship between species P50 values listed in Table 1 and soluble protein and ortho-dihydroxyphenol content in mature seeds (data from Hendry et al., 1994). Ortho-dihydroxyphenol has fungistatic properties and is associated with persistence of seeds in the soil. Symbols represent different families (e.g. Poaceae (solid circle), Fabaceae (open square), Asteraceae (open circle), Brassicaceae (closed triangle)], with the full key given in Table 1. Summary and conclusions This paper consolidates germination data from over 30 years of storage at 5 and 2 188C and near optimal moisture conditions for 276 species in the USDA NPGS collection. Summarized datasets for species are available from the corresponding author. The analyses provide general information on the storage behaviour of species and provide a broader context for the hypothesis that seeds of individual species have characteristic potential life spans. Consistent ranking of relative seed longevity among storage experiments is an important step in verifying that species have particular ageing tendencies. Further studies are required to show that the demonstrated variation of ageing rates among species is greater than the intraspecific variation. Documentation of the Figure 8. The relationship between species P50 values and parameters relating to resource allocation to seeds: seed mass (A) (data from Jones and Earle, 1966; AOSA, 2003), relative yield (B) and nitrogen uptake by plants (C) (data for B and C from Sinclair and DeWit, 1975). Symbols represent different families [e.g. Poaceae (solid circle), Fabaceae (open square), Asteraceae (open circle), Cucurbitaceae (closed square), Brassicaceae (closed triangle)], with the full key given in Table 1. general trends and variability of seed longevity provides a foundation for future investigations on the mechanisms of damage and protection during ageing stress. The idea that species have characteristic seed longevities is important in genebank scenarios, where the frequency of monitoring viability is set by arbitrary standards if biological standards are undefined. Genebank operators must also be able to predict if an accession will have superior or substandard Longevity of seedbank-stored seeds storage, which requires a reference to expected behaviour. The study of species with exceptional (either short or long) shelf lives in an evolutionary context should provide better insights about the genetic factors that contribute to seed storability, and lead to a better understanding of the mechanisms of seed deterioration in storage and the role of seed longevity in the domestication of crops. Acknowledgements The authors wish to ackn...
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This note was uploaded on 03/03/2013 for the course SFSF 202 taught by Professor Sf during the Spring '13 term at Cambridge.

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