Grain size and shape are important components of grain yield and quality and have been under selection since cereals were first domesticated. Here, we show that a quantitative trait locus GW8 is synonymous with OsSPL16, which encodes a protein that is a positive regulator of cell proliferation. Higher expression of this gene promotes cell division and grain filling, with positive consequences for grain width and yield in rice. Conversely, a loss-of-function mutation in Basmati rice is associated with the formation of a more slender grain and better quality of appearance. The correlation between grain size and allelic variation at the GW8 locus suggests that mutations within the promoter region were likely selected in rice breeding programs. We also show that a marker-assisted strategy targeted at elite alleles of GS3 and OsSPL16 underlying grain size and shape can be effectively used to simultaneously improve grain quality and yield.

A series of cyanoethyl cellulose (CEC) samples were synthesized from cellulose in NaOH/urea aqueous solutions by a homogeneous method. Structure and properties of CECs were characterized with FT-IR, 1 H and 13 C NMR, DSC, SEC-LLS, polarized light microscopy and solubility measurements. The total DS values of the obtained CECs were in the range of 0.26 to 1.93, and the relative reactivity of hydroxyl groups is in the order C-6 > C-2 > C-3. As the molar ratio of acrylonitrile to anhydroglucose unit (AGU) of cellulose increased to 5 : 1, the C-6 hydroxyl groups of AGU were fully substituted. The total DS value for water-soluble CEC is as low as 0.54. CEC could be dissolved in many organic solvents when its total DS value reached 1.37. Organic-soluble CEC samples displayed thermotropic liquid crystalline behavior in the temperature range of 180 to 280 C. Moreover, NaOH/urea aqueous solution was proved to be a stable medium for cyanoethylation of cellulose, the reaction products could be easy isolated and purified, and the solvents could be recycled by a simple filtration. Therefore, this work provides a facile method for the homogeneous synthesis of CEC in an aqueous system. Experimental MaterialsCellulose (cotton linter pulp) was supplied by Hubei Chemical Fiber Group Ltd. (Xiangfan, China), and the viscosity-average

Cellulose carbamates (CCs) were microwave-assisted synthesized from the native cellulose and urea under solvent-free and catalyst-free conditions. Types of raw materials, the effects of the reaction condition on the nitrogen content of CCs were investigated. CCs were characterized with infrared spectroscopy (FT-IR), 13 C NMR spectrometry, X-ray diffraction, scanning electron microscopy and thermogravimetry. The results indicated that various source of native celluloses such as cotton linter, reed, bagasse and wood pulps with different degree of polymerization could be successfully converted to CCs by the efficient and environmentally friendly procedure. The nitrogen content of CCs increased with an increase of the urea content and the mass of the mixtures, as well as the pulsed times of microwave irradiation. CCs retained the cellulose I crystalline form of the native cellulose and the degree of crystallinity decreased with the incorporation of carbamates. This work provided a novel pathway for the preparation of cellulose carbamate, which is expected to be useful for the CarbaCell process.

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