| 摘要: |
| 【目的】探究不同胚乳类型玉米灌浆结实期籽粒的超微结构和品质指标的动态变化，为不同类型玉米的加工利用及品质改良提供理论依据。【方法】以超甜玉米超甜2000、糯玉米京科糯2000及普通玉米郑单958为试验材料，利用近红外光谱分析仪、扫描电镜，对不同胚乳类型玉米籽粒营养品质及超微结构进行观测分析。【结果】授粉后10 d时，超甜2000、京科糯2000和郑单958的淀粉粒均呈圆球状，随着灌浆进程，京科糯2000淀粉粒被挤压成多面体状和椭圆状，凹陷的淀粉粒较多，超甜2000淀粉粒为圆球状，表面光滑，郑单958淀粉粒为多面体状，凹陷的淀粉粒较少。授粉后10～20 d淀粉粒的体积、数目增加最快。淀粉粒的排列紧密程度表现为超甜2000＞郑单958＞京科糯2000，超甜2000胚乳细胞中蛋白质和可溶性糖含量较郑单958和京科糯2000丰富，且其淀粉粒与基质蛋白的结合更紧密。灌浆结实期，3种类型玉米籽粒淀粉的积累呈“S”型增长曲线，授粉后10～20 d增长速率最快，蛋白质和可溶性糖含量随授粉后时间的增加呈下降趋势，整个灌浆期内，甜玉米淀粉含量始终低于糯玉米和普通玉米。【结论】在灌浆结实期，超甜2000、京科糯2000和普通玉米郑单958淀粉粒的外形、数目及与基质蛋白和可溶性糖结合的紧密程度均存在差异，且随授粉后时间的延长，不同类型玉米籽粒淀粉上升的趋势与可溶性糖下降的趋势相吻合，结合籽粒超微结构观察，可初步鉴别玉米品质的优劣及鲜食玉米的适宜采收期。 |
| 关键词: 玉米籽粒 营养品质 超微结构 胚乳类型 |
| DOI： |
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| 基金项目:西北农林科技大学唐仲英育种基金项目(A212020802) |
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| Dynamic changes of ultra-structure and nutritional quality in maize kernels with different endosperm types |
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MA Xiu-feng,GUO Qiang,LIN Chong-ming,et al
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| Abstract: |
| 【Objective】This study explored the dynamic changes of nutritional quality and internal ultra structure in maize kernels with different endosperm types during grain filling period to provide theoretical basis for the processing and quality improvement of different corn varieties.【Method】Internal structures in kernels of super sweet corn (Super sweet 2000),waxy corn (Jingkenuo 2000) and common corn (Zhengdan 958) were explored using near infrared spectroscopy analyzer (NISA) and scanning electron microscopy (SEM).【Result】10 days after pollination,grains of Super sweet 2000,Jingkenuo 2000 and Zhengdan 958 starch were round in shape.With the processing of grain filling,the starch granules of Jingkenuo 2000 extruded into polyhedral and elliptical with many depressed starch granules,starch granules of Super sweet 2000 were spherical with smooth surface,while starch granules of Zhengdan 958 were polyhedral with small quantity of depressed starch granules.The number and size of starch grains rapidly increased 10 to 20 days after pollination.Starch granules arranged closely in the order of Super sweet 2000>Zhengdan 958>Jingkenuo 2000.Protein and soluble sugar contents in Super sweet 2000 endosperm cell were higher than in Zhengdan 958 and Jingkenuo 2000,and the starch grains and matrix protein combined more closely in Super sweet 2000 cell.In grain filling stage,the grain starch accumulation presented in “S shape” curve with the largest growth rate 10 to 20 days after pollination.Protein and soluble sugar contents gradually decreased and starch content of super sweet corn was always lower than that of waxy corn and common corn.【Conclusion】In the grain filling stage,the appearance,number and combination of matrix protein and soluble sugar of starch grains of Zhengdan 958,Jingkenuo 2000 and Super sweet 2000 were all different.With the extension of time after pollination,the upward trend of starch coincided with the downward trend of soluble sugar.Observation of grain ultra-structure could be used for preliminary identification of the maize quality and determination of suitable harvest time for fresh corn. |
| Key words: corn kernel nutrient quality ultra-structure endosperm type |
