Accumulation of soluble carbohydrates during seed development and maturation of low-raffinose, low-stachyose soybean
Soybean [Glycine max (L.) Merr.] seeds accumulate sucrose, raffinose family oligosaccharides (RFO), phytin, and small amounts of galactopinitols and fagopyritols during normal seed maturation. RFO and phytin are indigestible by non-ruminant animals and contribute to decreased feed efficiency, reduced mineral adsorption, and phosphorous pollution in manure. Low raffinose, stachyose, and phytin seed may have imbibitional chilling sensitivity and reduced field emergence. The objective was to characterize the profiles of soluble carbohydrates in cotyledons, axis, and seed coats of low raffinose and stachyose (LRS) seeds expressing the mutant stc1 phenotype; in low raffinose, stachyose, and phytin (LRSP1, LRSP2) seeds expressing the mutant mips phenotype; and in normal raffinose, stachyose, and phytin (CHECK) seeds expressing the Stc1 and Mips phenotype during 17 stages of soybean seed development, maturation, and desiccation. Seventy percent of RFO accumulated after maximum seed dry weight during seed desiccation. LRS, LRSP1, and LRSP2 seeds had low RFO, but LRS seeds accumulated higher galactinol and di- and tri-galactosides of myo-inositol, D-chiro-inositol, and D-pinitol earlier during seed maturation than CHECK, LRSP1, and LRSP2. LRSP1 and LRSP2 seed had low RFO and low galactosyl cyclitols during maturation and were reported to have imbibitional chilling sensitivity and reduced field emergence.