Water uptake and oil distribution during imbibition of seeds of western white pine (Pinus monticola Dougl. ex D. Don) monitored in vivo using magnetic resonance imaging.
ABSTRACT Dry or fully imbibed seeds of western white pine (Pinus monticola Dougl. ex D. Don) were studied using high-resolution magnetic resonance imaging (MRI). Analyses of the dry seed revealed many of the gross anatomical features of seed structure. Furthermore, the non-invasive nature of MRI allowed for a study of the dynamics of water and oil distribution during in situ imbibition of a single seed with time-lapse chemical shift selective MRI. During soaking of the dry seed, water penetrated through the seed coat and megagametophyte. The cotyledons of the embryo (located in the chalazal end of the seed) were the first to show hydration followed by the hypocotyl and later the radicle. After penetrating the seed coat, water in the micropylar end of the seed likely also contributed to further hydration of the embryo; however, the micropyle itself did not appear to be a site for water entry into the seed. A model that describes the kinetics of the earlier stages of imbibition is proposed. Non-viable pine seeds captured with MRI displayed atypical imbibition kinetics and were distinguished by their rapid and uncontrolled water uptake. The potential of MR microimaging for detailed studies of water uptake and distribution during the soaking, moist chilling ("stratification"), and germination of conifer seeds is discussed.
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ABSTRACT: Magnetic resonance imaging (MRI) is a superior noninvasive diagnostic tool widely used in clinical medicine, with more than 60 million MRI tests performed each year worldwide. More specialized high-resolution MRI systems capable of a resolution that is 100-1,000 times higher than standard MRI instruments are used primarily in materials science, but are used with increasing frequency in plant physiology. We have shown that high-resolution (1)H-nuclear magnetic resonance (NMR) microimaging can provide a wealth of information about the internal anatomy of plant seeds as small as 1 mm or even smaller. This chapter covers the methods associated with these imaging techniques in detail. We also discuss the application of (1)H-NMR microimaging to study in vivo seed imbibition, germination, and early seedling growth.Methods in molecular biology (Clifton, N.J.) 01/2011; 773:319-27.
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ABSTRACT: Low field NMR has been successfully used for the evaluation of seed composition and quality, but largely only in crop species. We show here that 1.5T NMR provides a reliable means for analysing the seed lipid fraction present in a wide range of species, where both the seed size and lipid concentration differed by >10 fold. Little use of high field NMR has been made in seed research to date, even though it potentially offers many opportunities for studying seed development, metabolism and storage. Here we demonstrate how 17.5T and 20T NMR can be applied to image seed structure, and analyse lipid and metabolite distribution. We suggest that further technical developments in NMR/MRI will facilitate significant advances in our understanding of seed biology.Materials 08/2011; 4(8):1426-1439. · 1.68 Impact Factor