Browsing by Person "Zhang, Xudong"

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    The effects of fermentation of Qu on the digestibility and structure of waxy maize starch
    (2022) Wu, Wenhao; Zhang, Xudong; Qu, Jianzhou; Xu, Renyuan; Liu, Na; Zhu, Chuanhao; Li, Huanhuan; Liu, Xingxun; Zhong, Yuyue; Guo, Dongwei
    The fermentation of Qu (FQ) could efficiently produce enzymatically modified starch at a low cost. However, it is poorly understood that how FQ influences the waxy maize starch (WMS) structure and the digestion behavior. In this study, WMS was fermented by Qu at different time and starches were isolated at each time point, and its physico-chemical properties and structural parameters were determined. Results showed that the resistant starch (RS), amylose content (AC), the average particle size [D(4,3)] the ratio of peaks at 1,022/995 cm–1, and the onset temperature of gelatinization (To) were increased significantly after 36 h. Conversely, the crystallinity, the values of peak viscosity (PV), breakdown (BD), gelatinization enthalpy (ΔH), and the phase transition temperature range (ΔT) were declined significantly after 36 h. It is noteworthy that smaller starch granules were appeared at 36 h, with wrinkles on the surface, and the particle size distribution was also changed from one sharp peak to bimodal. We suggested that the formation of smaller rearranged starch granules was the main reason for the pronounced increase of RS during the FQ process.
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    Translocation and storage of chloride in chlorine-stressed maize (Zea mays L.)
    (2020) Zhang, Xudong; Zörb, Christian
    Maize (Zea mays L.) is a moderately salt-sensitive species, its sensitivity to NaCl being mainly associated with the accretion of toxic sodium in shoots for example leading to the sodium-induced damage of leaf chloroplasts. However, less attention has been paid to the effects of chloride (Cl-). The work described in this dissertation therefore aims at elucidating the physiological adaptations of maize plants to Cl- salinity. It involves four research questions: 1) how do sensitive maize plants respond to Cl- salinity with regard to crop yield and plant performance; 2) how are the translocation and tissue storage patterns of Cl- correlated with tolerance to Cl- salinity; 3) how do osmotic stress and Cl- stress impact biomass, chlorophyll content, and nitrate reductase activity (NRA); 4) does sensitivity to Cl- salinity differ between maize and faba bean plants? Soil pot experiments and hydroponic culture experiments in the greenhouse have shown that maize is able to withstand Cl- salinity by being a shoot excluder. The relevant genotypic difference is believed to be based on its ability to undertake Cl- root-to-shoot translocation. The resistance mechanism of the genotype ES-metronom, which is a more Cl- -tolerant variety, has been attributed to its more efficient shoot exclusion of Cl-,whereas that of the genotype P8589, which is a more Cl- -sensitive variety has been ascribed to the preferable sequestration of Cl- away from the young photosynthetic tissues, such as into old leaf blades, and Cl- movement in roots possibly to achieve Cl- dilution. In the mildly tolerant genotype LG30215, osmotic stress does not interfere with NRA but slows down mass flow, which probably reduces NO3- transport to leaf tissues, whereas excess Cl- indirectly inhibits NRA through the antagonistic limitation of NO3- uptake. In comparison with maize, faba bean plants are more sensitive to Cl- salinity rather than to sodium toxicity.