施氮量对糯小麦和非糯小麦籽粒淀粉组分与理化特性的影响

为探明氮肥对小麦籽粒淀粉组分和理化特性的影响,采用田间试验,分析了4个施氮量(0、100、200、300kg·hm~(-2))对糯小麦(农大糯50222)和非糯小麦(轮选987)籽粒淀粉组分与理化特性的影响。结果表明,随施氮量的增加,小麦籽粒淀粉含量降低,轮选987籽粒中B型淀粉粒的数目占比增加,而农大糯50222籽粒的B型淀粉粒数目占比呈减少趋势;增施氮肥能显著提高小麦籽粒淀粉的峰值黏度和谷值黏度。相同施氮量处理下,轮选987淀粉的被测糊化特征参数(除谷值黏度外)均大于农大糯50222。施氮量不同,2个品种籽粒淀粉X-衍射图谱中各峰的位置和相对强度明显不同。随施氮量的增加,轮选987淀粉的相对结晶度增大,而农大糯50222淀粉的相对结晶度减小。相关分析表明,小麦籽粒的直链淀粉含量和直支比与最终黏度、稀澥值、反弹值、糊化温度和峰值时间呈显著正相关,与谷值黏度和相对结晶度呈显著负相关;支链淀粉含量反之。小麦籽粒的B型淀粉粒数目占比与峰值黏度、稀澥值呈显著负相关。综上所述,施氮量可影响小麦籽粒的淀粉含量和粒度分布,进而改变其糊化特性和晶体特征。

Effect of Nitrogen Rate on Starch Composition and Physicochemical Properties of Waxy and Non-Waxy Wheat

To investigate the influence of nitrogen rate on wheat starch components and physicochemical properties,the waxy wheat Nongdanuo 50222(ND50222) and non-waxy wheat Lunxuan 987(LX987) were selected as the experimental materials to study the effect of nitrogen rate(0,100,200,and 300 kg N·hm^-2) on the composition and properties of starch. The results showed that with the increase of nitrogen rate ,wheat starch content was decreased; the ratio of B-type starch granule of LX987 was increased,while that of ND50222 was decreased. The increase of nitrogen application improved the peak viscosity and trough viscosity. The pasting parameters(except for the trough viscosity) of the LX987 starch were higher than those of ND50222 starch under the same nitrogen treatment. The position and the relative intensity of X-ray peak in the wheat starch were significantly changed with the different nitrogen rate.The relative crystallinity of LX987 starch was increased with the increase of nitrogen rate,however,that of ND50222 was decreased. Correlation analysis showed that amylose content and the amylose/amylopectin ratio were positive correlated with the peak viscosity,final viscosity,breakdown value,setback value,pasting temperature and the pasting time. The correlation between amylopectin content and the above indices were negative. The B-type starch granule proportion was significantly negatively correlated with peak viscosity and breakdown values. The application of nitrogen fertilizer affected the starch content and grain size distribution of wheat,and then affected the pasting properties and crystal properties.