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Cereal Research Communications
Authors: Y.P. Jing, D.T. Liu, X.R. Yu, F. Xiong, D.L. Li, Y.K. Zheng, Y.F. Hao, Y.J. Gu, and Z. Wang

Liu, Z., Wang, L.L., Zhou, W.D., Chen, Y.F., Wang, Z. 2011. The surface of the geometric characteristics analysis for rice endosperm starch granules by using Image J. J. of Chinese Electron Microscopy Society 30 :466–471. (in Chinese with English

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To study the development of starch granules in polyploid wheats, we investigated the expression of starch synthetic genes between the synthetic hexaploid wheat SHW-L1, its parents T. turgidum AS2255 and diploid Ae. tauschii AS60. The synthetic hexaploid wheat SHW-L1 showed significantly higher starch content and grain weight than its parents. Scanning electron microscopy (SEM) showed that SHW-L1 rapidly developed starch granules than AS2255 and AS60. The amount of B-type granule in AS60 was less than that in SHW-L1 and AS2255. RT-qPCR result showed that the starch synthetic genes AGPLSU1, AGPLSU2, AGPSSU1, AGPSSU2, GBSSI, SSIII, PHO1 and PHO2 expressed at earlier stages with larger quantity in SHW-L1 than in its parents during wheat grain development. The expression of the above mentioned genes in AS60 was slower than in SHW-L1 and AS2255. The expression pattern of starch synthase genes was also associated with the grain weight and starch content in all three genotypes. The results suggested that the synthetic hexaploid wheat inherited the pattern of starch granule development and starch synthase gene expression from tetraploid parent. The results suggest that tetraploid wheat could plays more important role for starch quality improvement in hexaploid wheat.

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Journal of Thermal Analysis and Calorimetry
Authors: L. Lacerda, M. da Silva Carvalho Filho, I. Demiate, G. Bannach, M. Ionashiro, and E. Schnitzler

Abstract  

Corn starch, partially hydrolyzed by fungal α-amylase was investigated by using thermal analysis, microscopy and X-ray diffraction. After enzymatic treatment lower degradation onset temperatures were observed. DSC analysis showed almost similar range of gelatinization temperature, however, the enthalpies of gelatinization increased for the partially hydrolyzed starch granules. According to the X-ray diffraction analysis, stronger cereal pattern peaks were recognized after enzymatic digestion. The results suggested that the hydrolysis was more pronounced in the amorphous part of the starch granules.

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Introduction Starch is an important polysaccharide that is stored in granular form in plants. Starch granules are composed of two biopolymers: amylose and amylopectin. Amylopectin is a highly branched molecule that consists of

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). L each , H.W. , M c C owen , L.D. & S choch , T.J. ( 1959 ): Structure of the starch granule I. Swelling and solubility patterns of various starches . Cereal Chem. , 36 , 534 – 544

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stone cells were found here; 3) T. asiatica stem bark was brown, more cork cells, calcium oxalate square crystals, brown clumps and starch granules were its main microscopic powder characteristics, which were similar to T. asiatica root bark; 4) T

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Structure of starches extracted from near isogenic wheat lines

Part I. Effect of different GBSS I combinations

Journal of Thermal Analysis and Calorimetry
Authors: S. Kozlov, T. Noda, E. Bertoft, and V. Yuryev

Abstract  

Differential scanning calorimetry (DSC), acidic hydrolysis and different physico-chemical approaches were used to study thermodynamic and structural characteristics of starches from near-isogenic wheat lines to establish the effect of different combinations of active granule-bound starch synthase isoforms, taking part in amylose biosynthesis, on the structure and thermodynamic properties of starches. Obtained results suggest that the effect of different GBSS I combinations is realized through altered amylose localization within starch granules, reflecting in changes of melting temperature of crystalline lamellae (T m) and rates of acidic hydrolysis. It has also been demonstrated that changes in T m values for native wheat starches are determined by amylose content in amylopectin clusters.

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Drought-tolerant Plainsman V and drought-sensitive Cappelle Desprez winter wheat genotypes were subjected to heat stress at 34/24°C combined with water withholding during early seed development in order to identify the joint effect of the stressors on embryo and endosperm development. During and after five days of treatment histological observations were made on the developing kernels and compared to yield data. Combined stress shortened the duration of the grain fill. With regard to kernel abortion, thousand-kernel weight and yield per spike, Plainsman V tolerated simultaneous elevated temperature and water withdrawal better than Cappelle Desprez. As a consequence of the stress the accumulation of B-type starch granules was almost completely absent in the endosperms of the sensitive genotype. The results indicate that compared to the drought-sensitive genotype, the tolerant genotype also showed increased tolerance of simultaneous drought and heat stress.

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Abstract  

The aim of this work was to study the glass transition, the glass transition of the maximally freeze-concentrated fractions, the ice melting and the gelatinization phenomenon in dispersions of starch prepared using glycerol-water solutions. The starch concentration was maintained constant at 50 g cassava starch/100 g starch dispersions, but the concentration of the glycerol solutions was variable (C g= 20, 40, 60, 80 and 100 mass/mass%). The phase transitions of these dispersions were studied by calorimetric methods, using a conventional differential scanning calorimeter (DSC) and a more sensitive equipment (micro-DSC). Apparently, in the glycerol diluted solutions (20 and 40%), the glycerol molecules interacted strongly with the glucose molecules of starch. While in the more concentrated glycerol domains (C g>40%), the behaviour was controlled by migration of water molecules from the starch granules, due to a hypertonic character of glycerol, which affected all phase transitions.

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This study was conducted to compare structural development and biochemical accumulation of waxy and non-waxy wheat (NW) caryopses. The caryopses’ microstructure of the waxy wheat (WW) and NW cultivars at different developmental stages were observed under light, fluorescence, and scanning electron microscope. The results were as follows: Compared with NW,WWhad a shorter maturation duration, which was reflected in several following characteristics. Programmed cell death of the pericarp began earlier, and the chlorophyll-containing layer in the pericarp was smaller. Vacuoles in chalazal cells accumulated more tannins at different developmental stages. Starch granules and protein bodies in the endosperm showed a higher accumulation level in developing caryopses, and aleurone cells were larger in size with larger numbers of aleurone grains. An analysis of the element content indicated that the mineral elements Mg, P, K, and Ca exhibited a higher content, while the heavy elements Cr, Cd, and Pb exhibited a lower content in the aleurone layer.

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