摘要
【目的】淀粉粒粒度分布是评价淀粉品质的一个重要因素,环境因素对淀粉粒粒度分布的影响较大,水分和氮肥是玉米高产优质栽培中的主要农艺措施。因此,明确补充灌溉和施氮对玉米籽粒淀粉粒粒度分布特征的影响及其与淀粉糊化特性、粒重和淀粉组分之间的关系,能为玉米淀粉品质调控提供理论依据,也有利于玉米淀粉的定向加工利用。【方法】以郑单958为供试材料,设置雨养(W1)与补充灌溉(W2)两个水分处理,其中补充灌溉处理以土壤含水量是否低于田间持水量的60%来确定是否灌水,以灌水后土壤含水量达到田间持水量的80%来确定灌水量,其计算公式为m=10ρbH(?i-?j),式中m为补灌量(mm),H为该时段补充灌溉深度(cm),ρb为补充灌溉深度土壤容重(g·cm-3),βi为目标含水量(田间持水量×目标相对含水量),βj为自然含水量;按每生产100 kg籽粒耗氮3 kg,在67 500株/hm2种植密度下产量达10 500 kg·hm-2的标准设计最高氮肥处理,即设0(N1)、160(N2)、320(N3)kg·hm-2 3个氮肥处理。采用激光衍射粒度分析仪测定成熟期玉米籽粒淀粉粒体积、数目和表面积分布特性,借助RVA仪测定淀粉糊化特性,采用双波长法测定淀粉组分含量,并对淀粉粒体积分布与糊化特性、粒重、产量及淀粉组分做相关性分析。【结果】玉米籽粒淀粉粒粒径分布范围为0.38—39.78μm,其上限介于30.07—39.78μm。淀粉粒的体积和表面积表现为三峰分布,参照小麦研究中以双峰曲线凹处为分界线的分类方法,以3.5μm和7.4μm为界线,将玉米淀粉粒分为小型(<3.5μm)、中型(3.5—7.4μm)和大型(>7.4μm)三类。淀粉粒的数目表现为单峰分布,其中小型淀粉粒数目占总数的98%以上。增施氮肥及补充灌溉降低小型淀粉粒体积、表面积和数目的百分比,提高大型淀粉粒体积的百分比。施氮和补充灌溉增加玉米淀粉峰值黏度、谷值黏度、崩解值、最终黏度、回复值及籽粒产量、粒重、总淀粉和支链淀粉含量,降低峰值时间、糊化温度及直链淀粉含量和直/支比。直链淀粉含量、直/支比、峰值时间和糊化温度与小型淀粉粒的体积百分比呈极显著正相关,与大型淀粉粒的体积百分比呈极显著负相关;产量、粒重、支链淀粉和总淀粉含量、峰值黏度、谷值黏度、崩解值、最终黏度、回复值与小型淀粉粒的体积百分比呈极显著负相关,与大型淀粉粒的体积百分比呈(极)显著正相关。【结论】水分和氮肥处理显著影响淀粉粒的粒度分布和糊化特性,补充灌溉和施氮320 kg·hm-2时小型淀粉粒体积比最低,大型淀粉粒体积比最高,淀粉糊化特性最优。
[ Objective ] Starch granule size distribution is an important factor to evaluate starch quality and is greatly influenced by environmental factor. Irrigation and nitrogen are the major agronomic measures for high yield and good quality of maize. Therefore, it is very important for quality control and directional utilization of starch to clarify the effects of supplemental irrigation and nitrogen application on starch granule size distribution, and analyze the relationship between starch granule size distribution, grain weight, starch pasting properties and starch components of maize grain. [Method] In this study, Zhengdan 958 was used. Two water treatments were carried out, rain-fed （Wl） and supplemental irrigation （W2）. Supplemental irrigation treatment and irrigation amount were determined by soil water content. If soil water content was lower than 60% of field capacity, irrigation was applied. If soil water content after irrigation arrived 80% of field capacity, irrigation was stopped. Irrigation amount was calculated according to the formula of m=lOpbH（βi -βj）, where m is the amount of supplementary irrigation （mm）, H is the supplementary irrigation depth （cm） of the period, pb is soil bulk density（g.cm^-3） of the supplementary irrigation depth, βi is the objective water content （field capacityxobjective and relative water content）, βi is the natural water content. The highest nitrogen application rate was determined according to 3 kg nitrogen requirement for 100 kg kernels and the yield standard of 10 500 kg＇hm2 in 67 500 plants＇hm2 density. So, three nitrogen treatments were carried out, 0 （N1）, 160 （N2） and 320 （N3） kg.hm2. The volume, number and surface area distribution of starch granule in mature maize endosperm in irrigation and nitrogen application treatments were determined using laser particle size analyzer. Starch pasting properties were measured by RVA analyzer. Starch components were determined according to the double wavelengh method. The correlations between volume distribution of starch granule and starch pasting properties, kernel weight, yield and starch components were analyzed. [ Result] Starch granule of maize was in the range of 0.38-39.78 prn, and the upper limit was 30.07-39.78 prn. Starch granule volume and surface area showed a three-peak curve. According to the concave point of the double peak curve, taking 3.5 Ixm and 7.4 pm as limit, starch granules were divided into three types： small （〈3.5 gm）, middle （3.5-7.4 gm） and large （〉7.4 pm）. Starch granule number showed a single peak curve. Starch granule of maize grain was mainly composed of small starch granule, which accounted for over 98% of total starch granule. Nitrogen fertilization and supplemental irrigation reduced the percentages of volume, surface area and number of small starch granule, and increased the volume percentage of large starch granule. Nitrogen fertilization and supplementary irrigation increased starch peak viscosity, trough viscosity, breakdown, final viscosity, setback, grain yield and weight, total starch and amylopectin content, reduced peak time, pasting temperature, amylose content and the ratio of amylose to amylopectin. Correlation analysis indicated that amylose content, the ratio of amylose to amylopectin, peak time and pasting temperature were positively correlated with volume percentage of small starch granule, and negatively correlated with volume percentage of large starch granule. Grain yield and weight, amylopectin and total starch content, peak viscosity, trough viscosity, breakdown, final viscosity and setback were negatively correlated with volume percentage of small starch granule, and positively correlated with volume percentage of large starch granule. [ Conclusion] Water and nitrogen fertilization significantly affected starch granule size distribution and pasting properties. Supplemental irrigation and 320 kg.hm^2 nitrogen fertilization treatment had the lowest volume percentage of small starch granule, the highest volume percentage of large starch granule and the best starch pasting properties.
出处
《中国农业科学》
CAS
CSCD
北大核心
2014年第4期633-643,共11页
Scientia Agricultura Sinica
基金
国家自然科学基金(31101100)
作物生物学国家重点实验室开放课题(2013KF05)
山东省泰山学者建设工程项目
关键词
玉米
补充灌溉
施氮
淀粉
粒度分布
糊化特性
maize
supplemental irrigation
nitrogen application
starch
size distribution
pasting properties
