马铃薯块茎淀粉组分高效检测体系的建立及应用

马铃薯块茎淀粉组分(直链/支链淀粉比AM/AP)影响淀粉特性以及决定其在食品和其他工业上的应用。AM/AP的测定对其合理利用以及选育特异淀粉组分的专用品种等具有重要意义。采用96孔板双波长法对马铃薯不同AM/AP比率标准样品进行测试,发现当测试样品AM/AP比率超过制作标准曲线的AM/AP比率(33.3%)时,测试结果明显高估直链淀粉含量。基于96孔板的碘染分析,建立了马铃薯AM/AP比率和最大吸收峰下波长的标准曲线:y=601.88x0.0215,R2=0.9999。该方法进一步提高了测试准确度和应用范围。利用该方法测试了198个马铃薯品种(系)以及高直链淀粉组分的转基因块茎,明确了收集的马铃薯品种(系)的直链淀粉组成范围为17.4%~33.3%。新建立的马铃薯淀粉组分测试方法为高效准确筛选遗传育种材料以及改良淀粉组分株系提供了方便。     

GA3对葡萄果实淀粉积累及代谢相关酶活性的影响

以3a生全球红葡萄为试材,研究了用不同浓度的赤霉素（GA₃）在花前、花后2次处理葡萄果穗后,测定其对葡萄果实淀粉积累规律以及淀粉代谢酶活性的影响。结果表明:GA₃处理增加了葡萄果实可溶性糖积累速率,蔗糖合成酶（SS）活性增加,以20mg/L GA₃处理最为显著;经GA₃处理的果实前期淀粉含量有不同程度的增加,总淀粉酶、α-淀粉酶活性增大,而对β-淀粉酶无明显影响。因此,GA₃与淀粉积累调控机理之间存在密切的联系。     

高抗性淀粉粳稻新品系稻米淀粉链长分布与主要品质特征差异

 【目的】通过对水稻抗性淀粉性状的遗传研究,为高抗性淀粉水稻资源创新与育种提供理论和实践依据。【方法】以抗性淀粉含量有显著差异的粳稻品系为材料,比较分析高低抗性淀粉粳稻品系类型间的支链淀粉链长分布、稻米RVA谱特性值、膳食纤维和直链淀粉含量等主要品质特性的差异及其相关性。【结果】高低抗性淀粉水稻品系间支链淀粉链长分布差异显著,高抗性淀粉水稻品系的支链淀粉中短链部分即聚合度为5～12所占的相对百分比率显著低于低抗性淀粉类型品系,而长链尤其是聚合度为13以上的长链比率明显高于低抗性淀粉类型品系。膳食纤维和直链淀粉含量,高抗性淀粉品系显著高于低抗性淀粉品系,最高黏度值、最终黏度值、热浆黏度值和崩解值等,高抗性淀粉品系均显著或极显著低于低抗性淀粉类型品系。抗性淀粉含量与支链淀粉短链聚合度（DP≤12）呈极显著负相关,但与支链淀粉的中长链聚合度（12＜DP≤36）呈极显著正相关,与直链淀粉含量和膳食纤维含量呈极显著正相关。【结论】水稻中支链淀粉的链长分布、直链淀粉含量和稻米RVA谱特性值与稻米抗性淀粉含量关系密切,在育种实践中可作为育种选择指标之一。     

Evaluation of the waxy endosperm trait in proso millet (Panicum miliaceum)*

The entire USDA‐ARS maintained collection of 650 accessions of proso millet (Panicum miliaceum L.) was evaluated for the presence of accessions with waxy (amylose‐free) endosperm starch. Six accessions, five of which derived from mainland China, were identified. Segregation ratios for waxy endosperm were evaluated in F₂ and F₃ populations derived from crosses between two waxy accessions, PI 436625 (Lung Shu 16) and PI 436626 (Lung Shu 18), and several wild‐type accessions. The waxy trait was found to be under the control of duplicate recessive alleles at two loci, herein designated wx‐1 and wx‐2. Wild‐type alleles at these loci were designated Wx‐1 and Wx‐2. Iodine‐binding revealed a mean grain‐starch amylose concentration of 3.5% in waxy lines and 25.3% in wild‐type proso. Expression of the granule‐bound starch synthase (waxy protein) in waxy lines was reduced to approximately one‐tenth that of wild‐type accessions. The waxy accessions identified now are available for the introgression of this trait into breeding lines adapted to the Great Plains of North America.     

双波长比色法测定糜子中直链/支链淀粉含量

为建立一种同时测定糜子中直链和支链淀粉含量的简便方法,充实糜子理化性质的相关研究,首先应用双波长比色法,结合糜子直链淀粉/支链淀粉—碘复合物的吸收光谱图,确定其测定波长与参比波长。并利用标准工作曲线,求出样品中直链/支链淀粉的含量。由全波长扫描图谱确定了糜子中直链淀粉测定波长与参比波长分别为613 nm与520 nm,支链淀粉的测定波长和参比波长分别为538 nm与700 nm。结果表明,直链淀粉与支链淀粉的浓度分别在0~0.15 mg/mL和0~0.125 mg/mL呈线性相关。实验室用此法对15份糜子种质中直链与支链淀粉的含量进行测定。通过精密度与回收率实验,测得直链与支链淀粉的6次的标准偏差分别为0.145与0.022,回收率范围85.3%~97.9%。试验结果均满足分析要求,所建立的方法具有简便、快速、准确等特点,可用于测定糜子中直链和支链淀粉的含量。可对糜子口感及品质进行评价,从而筛选出优良种质。     

面包长期贮存过程中的硬化研究

本文研究了面包在长期贮存过程中的硬度变化。结果表明,面包硬度在贮存前几周不断增加,随后增加缓慢;检测分析发现,面包中支链淀粉的结晶和水分的迁移变化规律相似,合理使用添加剂可以延缓面包的硬化。     

Characterization of waxy grain sorghum lines in relation to granule-bound starch synthase

The waxy phenotype, associated with endosperm containing little or no amylose, has been recognized in sorghum (Sorghum bicolor L. Moench) since 1933. Although variants of the waxy gene are well characterized in other cereals, the waxy trait has been assumed to be controlled by a single allele, wx, in sorghum. Recent improvements in technologies encourage re-examination of the waxy sorghums. The objectives of this research were therefore to identify and characterize sorghum lines with differing waxy alleles and to describe the actions of those alleles in crosses. Grain of eight waxy sorghum lines (BTxARG1, BTx630, Tx2907, B.9307, 94C274, 94C278, 94C289, 94C369), three wild-type checks (BWheatland, RTx430, BN122), and F₂ families from crosses among a subset of these lines were evaluated for presence or absence of granule-bound starch synthase (GBSS), the gene product of the wx locus, and wild-type vs. waxy endosperm. The F₂ segregation ratios were tested for fit to a 3:1 ratio using Chi-square analyses. Two distinctly different naturally occurring waxy alleles were identified: One with no GBSS (GBSS−), and one with apparently inactive GBSS present (GBSS+). We propose that the waxy allele with no GBSS be designated wx^a, and that waxy allele with apparently inactive GBSS present be designated wx^b. These two alleles are located in close proximity on the waxy locus. The wx^b allele is dominant to the wx^a allele in terms of GBSS production, and both are recessive to the wild-type Wx in terms of amylose content. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

饲粮直链/支链淀粉和淀粉酶对肉鸡生长性能的影响及其互作效应研究

本试验旨在研究饲粮直链/支链淀粉和淀粉酶对肉鸡生长性能和营养物质表观消化率的影响。试验采用4×3双因子设计,选用1日龄爱拔益加(AA)肉仔鸡960只,随机分为12个组,每组5个重复,每个重复16羽肉鸡,饲粮直链/支链淀粉分别为0.11、0.23、0.35、0.47,淀粉酶的添加量分别为0、3000、6000U/kg。试验期为21d。试验测定了肉鸡生长性能和营养物质表观消化率。结果表明:1)直链/支链淀粉为0.23的饲粮组肉鸡的平均日增重显著提高(P<0.05),料重比以直链/支链淀粉为0.47的饲粮组最高(P<0.05),其他组间差异不显著(P>0.05);饲粮中添加6000U/kg淀粉酶显著降低肉鸡平均日增重(P<0.05),但对料重比影响不显著(P>0.05);二者的互作效应不显著(P>0.05)。2)能量、粗蛋白质、干物质、粗脂肪以及钙表观消化率以直链/支链淀粉为0.11的饲粮组最高(P<0.05),直链/支链淀粉为0.47的饲粮组最低(P<0.05);饲粮中添加淀粉酶对营养物质表观消化率影响不显著(P>0.05);二者的互作效应对营养物质表观消化率影响显著(P<0.05)。综上所述,饲喂直链/支链淀粉为0.23和淀粉酶添加量为3 000 U/kg的饲粮可提高肉鸡的生长性能。