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Comparison of post‐germination mobilization of cell wall polysaccharides and non‐cell wall carbohydrates in soybean ( Glycine max L.) cotyledons
Author(s) -
Gronwald John W,
Jung HansJoachim G,
Litterer Lynn A,
Somers David A
Publication year - 2009
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.3665
Subject(s) - cotyledon , seedling , arabinose , glycine , germination , hypocotyl , polysaccharide , rhamnose , botany , cell wall , biology , horticulture , xylose , chemistry , biochemistry , amino acid , fermentation
BACKGROUND: In previous research, we demonstrated that cell wall polysaccharide (CWP) levels of soybean ( Glycine max L.) cotyledons are negatively correlated with the sum of seed oil and protein content. Although the results suggest that reducing cotyledon CWP levels would be desirable, it is not known whether CWP are mobilized during early seedling growth and, if so, to what extent mobilization contributes to seed reserves. RESULTS: Ungerminated (dry) seeds contained equivalent amounts [approximately 20 mg (cotyledon pair) −1 ] of non‐cell wall carbohydrates (NCWC) and CWP. Galactose and arabinose accounted for 47% of total CWP in cotyledons of dry seeds. Measured 14 days after planting (DAP), the levels of NCWC and CWP were reduced 98% and 34%, respectively, in cotyledons of seedlings grown under a 16‐h photoperiod. Measured 14 DAP, greater than 85% of cotyledon cell wall galactose plus arabinose was mobilized. The transformation of the cotyledon to a photosynthetic organ was associated with restructuring of the cell wall involving increases in uronic acids, glucose and rhamnose. CONCLUSION: CWP of soybean cotyledons are modified during early seedling growth due to mobilization and cell wall restructuring triggered by light. The amount of carbon mobilized makes only a small contribution to total cotyledon reserves. Published 2009 by John Wiley & Sons, Ltd.