一份新的水稻斑点叶突变体spl32的鉴定和基因定位

从F2(粤晶丝苗2号/H4)群体中,鉴定出一份显性斑点叶突变体spl32(spotted leaf 32)。其叶片褐色斑点受自然光诱导,在幼穗分化期从叶尖逐渐扩散至叶鞘,台盼蓝染色表明斑点并非由细胞死亡引起。以从F5杂合个体分离出的正常叶色植株为对照,斑点叶植株的穗粒数、结实率显著降低。斑点出现后,spl32的POD活性和MDA含量均显著高于对照;同时,spl32叶片光合色素含量降低,但荧光动力学参数并无显著变化。抽穗期人工接菌表明,spl32对水稻白叶枯病菌抗性较对照显著提高。遗传分析表明spl32斑点性状由一个显性基因Spl32(t)控制,利用F2(02428/spl32)群体将其定位在第11染色体Ind-c和RM206之间,推测该基因为一个新的水稻斑点叶基因。     

彩叶植物呈色机理及光合特性研究进展

 本文在阐述彩叶植物的定义及分类的基础上, 介绍了呈色机理的研究进展, 总结了环境因子对叶片呈色的影响, 并归纳了近年来对彩叶植物光合特性的研究, 最后提出了彩叶植物未来的研究重点。     

New degreening treatments to improve the quality of citrus fruit combining different periods with and without ethylene exposure

In the Mediterranean area, early-season citrus fruit reach acceptable internal maturity standards for marketing, while the fruit are still green. A degreening treatment is widely used as a postharvest practice to improve the external color. Nevertheless, the application of ethylene during this treatment can be associated with calyx senescence. The aim of this study was to evaluate new degreening treatments in order to reduce this disorder. ‘Clemenules’ mandarins and ‘Navelina’ oranges, harvested at different external colors, were submitted to different degreening treatments, combining periods with and without ethylene exposure. In both cultivars, the periods without ethylene exposure during degreening reduced the incidence of calyx disorders. To obtain a typical ‘Clemenules’ variety color with the lowest incidence of calyx alteration, the optimum degreening treatment was based on 72 h with ethylene and 48 h without ethylene when fruit were harvested with a color index of between −9 and −3. On the other hand, a treatment of 24 h with ethylene plus 48 h without ethylene is recommended for fruit with an external color index higher than −2. For ‘Navelina’ oranges, highly sensitive to calyx senescence during degreening, a treatment consisting of 24 h with ethylene plus 48 h without ethylene is recommended, which involves harvesting the fruit with a color index of over 0.     

响应曲面法优化青花椒护色工艺

[目的]探索青花椒护色的最佳工艺条件。[方法]选取新鲜青花椒为原料,研究了护色剂、抗氧化剂、pH和杀菌条件对护色的影响。在单因素试验的基础上,选择CuSO4浓度、VC浓度和杀菌时间3个影响较大的因素,以色差值为指标,采用响应面试验优化新鲜青花椒护色条件。[结果]新鲜青花椒的最佳护色工艺为CuSO4浓度550 mg/L、VC溶液浓度1 000 mg/L、杀菌时间20 min。在此条件下处理后的青花椒在第15天的色差为10。[结论]该研究可为青花椒的护色研究提供理论和试验依据。     

建筑外部环境空间以小见大的手法探析

解析了建筑外环境空间大小的含义,以及"以小见大"空间设计手法。从静态观察和动态体验过程以及建筑外部环境场的尺度设计3个角度,探讨了建筑外部环境空间如何由"小"来得到美而丰富的空间体验的方法与途径。旨在尊重自然、顺应自然、尊重历史的前提下,精心设计建筑环境景观空间。     

嗜酸乳杆菌突变株产共轭亚油酸异构酶的纯化研究

以嗜酸乳杆菌NCFM和Lakcid作为出发菌株,通过紫外诱变及化学诱变筛选得到突变株.代谢亚油酸生成共轭亚油酸(CLA),研究转化过程中的关键性酶-亚油酸异构酶的酶学性质,采用硫酸铵沉淀、透析等对该酶进行纯化,用SDS-PAGE测得该酶的亚基分子量为60.5 ku;并得出该酶的最适温度是44℃,最适pH是6.0左右,金属离子Fe2+、K+对异构酶的反应有促进作用,Zn2+等对反应都起抑制作用.     

烟叶分级操作技能研究

依据烤烟分级国家标准,针对烟叶分级实际操作过程中的难点,从部位、颜色、级别3个角度进行技能、技术、技巧性分析,从而提出了烟叶识别难度图、烟叶生长等级位置图,旨在提高分级人员的技术水平。     

根癌农杆菌介导的真菌遗传转化研究进展

 农杆菌介导遗传转化成为真菌实现菌种改良、新基因标记及目的基因的筛选、分离和克隆的重要方法之一。该方法操作简单、受体范围广、转化效率高、单拷贝率高及突变体遗传稳定,解决了传统转化方法的瓶颈。利用该方法成功实现了多种真菌大容量高质量突变体库的构建,且在各类真菌突变体库构建的基础上,相关基因的筛选和功能基因的验证工作成为下一步的研究热点,进而为各类病原菌致病机理的深入研究提供依据,为抗病育种等亟待解决的问题奠定基础。     

一株灰葡萄孢细胞壁完整性缺陷突变株的分子鉴定和表型分析

为探明灰葡萄孢细胞壁相关基因功能,用荧光增白剂Calcofluor White（CFW）从灰葡萄孢T-DNA插入突变体库中筛选细胞壁完整性缺陷突变株,发现一株突变株D-59对CFW的敏感性与野生型相比提高了2.8倍。通过TAIL-PCR扩增突变株的T-DNA插入位点的侧翼序列并对其进行序列分析表明,T-DNA插入于突变株BC1G₀0770.1基因的外显子部位。RT-PCR的结果显示,D-59的BC1G₀0770.1基因不表达。突变株D-59的表型分析表明,突变株的菌丝稀疏,菌落呈土黄色,产孢量明显下降,孢子萌发异常,致病能力减弱,细胞壁的几丁质含量下降了48%。     

Effects of UV-C treatment on inactivation of Escherichia coli O157:H7, microbial loads, and quality of button mushrooms

This study investigated the effects of ultraviolet-C (UV-C) light applied to both sides of mushrooms on microbial loads and product quality during storage for 21 d at 4 °C. Microflora populations, color, antioxidant activity, total phenolics, and ascorbic acid were measured at 1, 7, 14 and 21 d of storage. Additionally, the inactivation of Escherichia coli O157:H7 by UV-C was determined. Results showed that UV-C doses of 0.45-3.15 kJ m⁻² resulted in 0.67-1.13 log CFU g⁻¹ reduction of E. coli O157:H7 inoculated on mushroom cap surfaces. UV-C radiation also reduced total aerobic plate counts by 0.63-0.89 log CFU g⁻¹ on the surface of mushrooms. Although mushrooms treated with UV-C had more severe browning with increasing dosage after initial treatment, the control mushrooms also browned as indicted by lower L* and higher a* values after 21 d of storage at 4 °C. In addition, the UV-C treatments apparently inhibited lesion development on the mushroom surface. During the first 7 d, irradiated mushrooms had lower antioxidant activity, total phenolics, and ascorbic acid content compared to non-radiated samples. However, irradiated mushrooms reached similar amounts of these nutrients as the control after 14 d of storage at 4 °C. In summary, UV-C radiation could potentially be used for sanitizing fresh button mushrooms and extending shelf-life.