Seed dormancy has been associated with red grain color in cereal crops for a century. The association was linked to qSD7-1/qPC7, a cluster of quantitative trait loci for seed dormancy/pericarp color in weedy red rice. This research delimited qSD7-1/qPC7 to the Os07g11020 or Rc locus encoding a basic helix-loop-helix family transcription factor by intragenic recombinants and provided unambiguous evidence that the association arises from pleiotropy. The pleiotropic gene expressed in early developing seeds promoted expression of key genes for biosynthesis of abscisic acid (ABA), resulting in an increase in accumulation of the dormancy-inducing hormone; activated a conserved network of eight genes for flavonoid biosynthesis to produce the pigments in the lower epidermal cells of the pericarp tissue; and enhanced seed weight. Thus, the pleiotropic locus most likely controls the dormancy and pigment traits by regulating ABA and flavonoid biosynthetic pathways, respectively. The dormancy effect could be eliminated by a heat treatment, but could not be completely overcome by gibberellic acid or physical removal of the seed maternal tissues. The dormancy-enhancing alleles differentiated into two groups basically associated with tropical and temperate ecotypes of weedy rice. Of the pleiotropic effects, seed dormancy could contribute most to the weed adaptation. Pleiotropy prevents the use of the dormancy gene to improve resistance of white pericarp cultivars against pre-harvest sprouting through conventional breeding approaches. SEEDS acquire primary dormancy during development to enhance adaptation of wild species to diverse environments by distributing germination over time and space. Domestication tends to reduce dormancy by selection for rapid, uniform germination (Harlan et al. 1973). Differentiation in seed dormancy between cereal crops and wild relatives has been associated with seed morphologies (Nilsson-Ehle 1914;Johnson 1935) and quantitative trait loci (QTL). Cloning of validated dormancy loci provides in-depth insights into regulatory mechanisms underlying natural variation in this adaptive or domestication-related trait (Bentsink et al. 2006;Sugimoto et al. 2010).Weedy rice refers to Oryza spp., which competes with cultivated rice (Oryza sativa L. and O. glaberrima Steud.) from tropical to temperate areas (Oka 1988;Delouche et al. 2007). The most persistent type of weedy rice is red rice, which is characterized by a red pericarp color. Red rice has strong seed dormancy (Cohn and Hughes 1981;Noldin et al. 2006). Genetic analysis has associated pericarp color with seed dormancy in red rice (Gu et al. 2005a).This association was first reported for wheat (Triticum aestivum L.), where red grain genotypes were more dormant than the white ones, and this morphology has been used to select cultivars for resistance to pre-harvest sprouting (NilssonEhle 1914;Flintham 2000). However, it remains unknown if the association in rice, wheat, and other crops arises from a tight linkage between genes for these two trai...

Capturing carbon dioxide is vital for the future of climate-friendly combustion, gasification, and steam-reforming processes. Dry processes utilizing simple sorbents have great potential in this regard. Long-term calcination/carbonation cycling was carried out in an atmospheric-pressure thermogravimetric reactor. Although dolomite gave better capture than limestone for a limited number of cycles, the advantage declined over many cycles. Under some circumstances, decreasing the carbonation temperature increased the rate of reaction because of the interaction between equilibrium and kinetic factors. Limestone and dolomite, after being pretreated thermally at high temperatures (1000 or 1100 °C), showed a substantial increase in calcium utilization over many calcination/carbonation cycles. Lengthening the pretreatment interval resulted in greater improvement. However, attrition was significantly greater for the pretreated sorbents. Greatly extending the duration of carbonation during one cycle was found to be capable of restoring the CO 2 capture ability of sorbents to their original behavior, offering a possible means of countering the long-term degradation of calcium sorbents for dry capture of carbon dioxide.

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