春小麦抗穗发芽机理的研究

春小麦穗发芽与种子休眠密切相关。胚及果皮中含有发芽抑制物质是导致休眠的主要原因;果皮的结构,尤其外表皮细胞的排列方式、形状在一定程度上控制着休眠深度。α-淀粉酶活性与穗发芽并非正相关,应从籽粒成熟过程中的变化趋势确定其与穗发芽的关系,但胚乳对赤霉素的不敏感性可做为抗穗发芽选择指标。本文还讨论了颖片、芒中的抑制物质及温度对穗发芽的影响。     

贵农小麦系列穗发芽抗性研究

１９９８～１９９９年对遗农小麦系列的九个材料进行了穗发芽的抗性和α－淀粉酶的同工酶研究，结果表明九个材料的抗穗发芽性能有着显著的差异，其中以贵农１０的穗发芽率最小，经过一周的发芽率为１．０％，二周的发芽率为４．５％，对照绵阳２６的发芽率最高，第一周为６７．０％，第二周为９８．６％，而α－淀粉酶的同工酶酶谱也表现出差异，绵阳２６和丰产３号这两个穗发芽率最高材料的同工酶酶带是最强的，其他材料的酶带都比     

The effect of storage temperature on reducing sugar concentration and the activities of three amylolytic enzymes in tubers of the cultivated potato,Solanum tuberosum L.

Summary Reducing sugar content, and activities of three starch hydrolysing enzymes, alpha-amylase, beta-amylase and debranching enzyme were measured over several months in tubers of five cultivars stored at 4°C or 10°C. Cultivars differed in their sensitivity to storage temperature. Reducing sugar content of tubers and the activities of three starch hydrolysing enzymes increased sharply during the first weeks of storage at 4°C. At 10°C, reducing sugar content, and the activity of the three enzymes remained constant or increased only slightly. Deceased.     

水稻穗发芽与籽粒内可溶性糖和α-淀粉酶活性的品种差异

对四个穗发芽能力不同的水稻品种籽粒潜在发芽势,可溶性糖含量和α-淀粉酶活性的测定结果表明:(1)所有供试品种在始穗10天后均有部分籽粒可以发芽。其中易穗发芽的珍汕97B的潜在发芽能力明显地高于不易穗发芽的协优64,加系758;(2)易穗发芽品种籽粒发育前期(始穗后5～20天)可溶性糖含量高,维持时间长,其峰值出现迟于不易穗发芽的品种,而且始穗后30天又出现第二峰值;(3)籽粒成熟后期易穗发芽品种α-淀粉酶活性为不易穗发芽品种的2～5倍。抑制剂2号时珍汕97B发芽有较强的抑制作用,并能相应降低籽粒内α-淀粉酶活性和可溶性糖的含量。因此,水稻穗上发芽现象与籽粒内较长时间维持高的可溶性糖的含量和α-淀粉酶活性有密切关系。     

Genetic variability of preharvest sprouting – the South African situation

Preharvest sprouting resistance is a major breeding criterion in many regions. Screening for preharvest sprouting tolerance is difficult owing to the low heritability of the trait and its tendency to be expressed as a quantitatively inherited character. The screening procedure used currently at the ARC-Small Grain Institute is designed to assess variation of sprouting in intact heads. Five winter wheat cultivars were crossed in a complete diallel fashion. The objectives of the study were to determine the genetic variability of sprouting resistance in the progeny of five winter wheat cultivars, including Elands, a cultivar with excellent sprouting resistance. The preharvest sprouting response and α-amylase activity of these cultivars and their ensuing progeny were compared. Elands was identified as contributing positively towards preharvest sprouting tolerance in various combinations. Elands also had the best overall combining ability for the improvement of sprouting tolerance.     

烤烟烘烤过程中淀粉酶及淀粉含量的变化

 通过对烤烟品种红花大金元和K326的3个施氮量的烟叶烘烤过程中α－淀粉酶、β－淀粉酶活性的变化和烟叶淀粉含量的研究得出如下结论。2个品种3个施氮量处理烟叶α－淀粉酶变化曲线都呈现双峰曲线,两个高峰出现在烘烤过程的36 h和60 h. β－淀粉酶变化的曲线也呈现双峰曲线,两个高峰值出现在烘烤后36 h和72 h. 2个品种3种施氮量处理烟叶淀粉含量都是从烘烤开始至48 h均迅速下降,烘烤48 h至烘烤结束烟叶淀粉含量下降趋势趋于平稳。     

基于体外降糖活性的桑葚渣水提物的超声辅助工艺优化

以桑葚渣为原料,采用超声辅助提取方法获得水提物并对其α-淀粉酶和α-葡萄糖苷酶的抑制活性进行检测,通过L₉(3⁴)正交试验优化了桑葚渣水提物的超声辅助工艺。结果表明:在最佳的提取工艺,即提取时间1.5 h、料液比1∶40(g·mL^-1)、超声温度50 ℃、超声功率350 W条件下,提取液对α-淀粉酶和α-葡萄糖苷酶活性的抑制率分别为76.4%、81.4%。     

Production and field performance of transgenic alfalfa (Medicago sativa L.) expressing alpha-amylase and manganese-dependent lignin peroxidase

Summary Transgenic alfalfa plants expressinBacillus licheniformis alpha-amylase and mangaese-dependent lignin peroxidase (Mn-P) from Phanerochaete chrysosporium were produced using the Agrobacterium tumefaciens transformation system. In each case, there was a range of expression of the introduced gene among independent transgenic plants. Plants producing alpha-amylase showed no alteration of phenotype. Production of Mn-P in alfalfa, howeven, in most cases adversely affected plant growth and development. Affected plants were stunted with yellowing foliage, but survived and produced seed. Results from field trials showed that Mn-P production in transgenic alfalfa reduced dry matter yield and plant height. The extent of these symptoms and yield reduction was, for the most part, related to the level of foreign protein production as estimated by Western analysis. Field data from transgenic plants expressing alpha-amylase showed that there was no effect of foreign protein production on plant performance. Expression of Mn-P was shown to segregate in sexual progeny derived from transgenic plants.Abbreviations Mn-P manganese-dependent lignin peroxidase     

九孔鲍幼鲍生长性状的遗传参数估计

实验采用cDNA末端快速扩增（RACE）和反转录聚合酶链式反应（RT-PCR）技术对九孔鲍（Haliotis diversicolor supertexta）α-淀粉酶基因cDNA进行克隆,并分析该基因的组织表达及其与生长性状的相关性。结果表明,九孔鲍α-淀粉酶基因cDNA全长为2 260 bp,其中开放阅读框长度为2 088 bp,共编码695个氨基酸。经SingalP分析,α-淀粉酶多肽链中含有信号肽结构,且长度为18个氨基酸（MWAQYGIVSALLVLSASA）,由该多肽链折叠成的三级结构中含有domain A、domain C 2个结构域,并且在domain A第28~第396氨基酸处存在催化中心。该基因在九孔鲍右侧壳肌、肠、肝脏、胃、外套膜、吻、腹足7种组织中均有不同程度表达。其中在胃中表达量最高,表达量高达326.803;而在外套膜中表达量最低,表达量仅为0.35。经ANOVA分析,消化组织与非消化组织间的α-淀粉酶基因表达量存在显著差异（P < 0.05）。α-淀粉酶基因mRNA表达量与生长性状呈显著正相关（P < 0.05）。