Ahmed N.,University of Agriculture at Faisalabad |
Tetlow I.J.,University of Guelph |
Nawaz S.,University of Agriculture at Faisalabad |
Iqbal A.,University of Agriculture at Faisalabad |
And 5 more authors.
Journal of the Science of Food and Agriculture | Year: 2015
BACKGROUND: High temperature during grain filling affects yield, starch amylose content and activity of starch biosynthesis enzymes in basmati rice. To investigate the physiological mechanisms underpinning the effects of high temperature on rice grain, basmati rice was grown under two temperature conditions - 32 and 22 °C - during grain filling. RESULTS: High temperature decreased the grain filling period from 32 to 26 days, reducing yield by 6%, and caused a reduction in total starch (3.1%) and amylose content (22%). Measurable activities of key enzymes involved in sucrose to starch conversion, sucrose synthase, ADP-glucose pyrophosphorylase, starch phosphorylase and soluble starch synthase in endosperms developed at 32 °C were lower than those at 22 °C compared with similar ripening stage on an endosperm basis. In particular, granule-bound starch synthase (GBSS) activity was significantly lower than corresponding activity in endosperms developing at 22 °C during all developmental stages analyzed. CONCLUSION: Results suggest changes in amylose/amylopectin ratio observed in plants grown at 32 °C was attributable to a reduction in activity of GBSS, the sole enzyme responsible for amylose biosynthesis. © 2014 Society of Chemical Industry.
Umagiliyage A.L.,Soil and Agricultural Systems |
Choudhary R.,Soil and Agricultural Systems |
Liang Y.,SIU |
Haddock J.,SIU |
Watson D.G.,Soil and Agricultural Systems
Industrial Crops and Products | Year: 2015
Sweet sorghum has been identified as a promising feedstock for biological conversion to fuels as well as other chemicals. The lignocellulosic stalk of sweet sorghum, called sweet sorghum bagasse (SSB) is a potential source of lignocellulosic biofuel. The primary goal of this study was to determine optimal alkali (lime: Ca(OH)2 and lye: NaOH) pretreatment conditions to obtain higher yield of total reducing sugar while reducing the lignin content for biofuel production from SSB. Biomass conversion and lignin removal were simultaneously optimized through four quadratic models analyzed by response surface methodology (RSM). The optimal conditions for lime pretreatment was 1.7% (w/v) lime concentration, 6.0% (w/v) SSB loading, 2.4h pretreatment time with predicted yields of 85.6 total biomass conversion and 35.5% lignin reduction. For lye pretreatment, 2% (w/v) alkali, 6.8% SSB loading and 2.3h duration were the optimal levels with predicted biomass conversion and lignin reduction of 92.9% and 50.0%, respectively. More intensive pretreatment conditions removed higher amounts of hemicelluloses and cellulose. Fourier transform infrared spectroscopy (FTIR) spectrum and scanning electron microscope (SEM) image revealed compositional and microstructural changes caused by the alkali pretreatment. © 2015 Elsevier B.V.