白东魁和东魁不同发育阶段果实的花青苷组分及含量差异分析

白东魁是从东魁杨梅群体中发现的粉色果实的杨梅变异株系,为研究东魁和白东魁果实色泽差异的形成机理,运用液相色谱串联质谱（LC-MS/MS）技术分析了两个品种3个不同发育阶段果实中的花青苷种类和相对含量。结果表明：两个品种的成熟果实中均可以检测出7种花青苷,分别为矢车菊素-3-O-葡萄糖苷,矢车菊素-3-O-阿拉伯糖苷,矢车菊素-3-O-鼠李糖苷,飞燕草素-3-O-葡萄糖苷,飞燕草素-3,5-O-二葡萄糖苷,天竺葵素-3-O-葡萄糖苷和芍药色素-3-O-葡萄糖苷,但飞燕草素-3,5-O-二葡萄糖苷在东魁和白东魁的幼果期和转色期均未检测到。白东魁成熟果实中除矢车菊素-3-O-鼠李糖苷外,其它6种花青苷含量均显著低于东魁,尤其杨梅果实中最主要的矢车菊素-3-O-葡萄糖苷,在白东魁果实中的含量只有东魁的13.93 %,从而导致了两个品种成熟果实间色泽的巨大差异。     

基于纹理和位置特征的麦田杂草识别方法

以化学防除适期麦田杂草为研究对象,对利用条播作物的位置和纹理特征识别田间杂草的方法进行了研究。根据条播作物小麦作物行的间距相对固定等位置特征,利用植物像素直方图法确定作物行的中心线和行宽,并识别行间杂草。然后,以作物行中心为基准来选取纹理块,计算量化级数为8级的H颜色空间的共生矩阵,提取5个纹理特征参数,利用K均值聚类法判别分析各块的类别来识别行内杂草。研究结果表明,杂草的正确识别率约为93％,作物的错误识别率约为7％。     

Tapetal behaviour, gene action and breeding value in male-sterile peas

Eight non-allelic male-sterile mutants controlled by a single recessive gene were induced in garden pea (Pisum sativum) after EMS, DES and gamma-ray-mutagen treatments singly and in combination. These mutants differ in the time and type of tapetal development due to differential action of male-sterile (ms) genes over the sporogenous and non-sporogenous anther tissue. In the msg1 mutant, the sporogenous tissue breaks down during premeiosis, followed by tapetal degeneration. In msg2, sporogenous tissue and tapetal tissue exhibit anomalies at early and late prophase 1, respectively. Although in msg3 and msg5 the ms gene action over sporogenous tissue initiates during early and late prophase, respectively, the tapetal tissue breaks down during post-meiosis. In msg6, anomalies in the sporogenous tissue appear during prophase II, but the tapetum degenerates during the mononucleate stage. Although both the tapetal and sporogenous tissue anomalies appear simultaneously at pachytene in msg4, the tapetal breakdown is delayed until the microspore stage. In msg7 and msg8, anomalies in both these tissues occur simultaneously during the tetrad and post-meiotic stages, respectively. Despite differences in the timing of tapetal and sporogenous tissue breakdown, tapetal development is normal in msg1, msg5, msg6, msg7 and nisg8 but abnormal in msg2, msg3 and msg4. The ms gene action is dual in msg2, msg3 and msg4 but single in msg1, msg5, msg6, msg7 and msg8. In all these mutants, the time of tapetal anomaly exhibits no correlation with the time of ms gene action. The gene for open flower found in one male-sterile mutant needs to be introduced into fertile peas for commercial hybrid-pea breeding.     

水稻种子萌动期抗低温逆境突变体的筛选

利用粳稻(Oryza sativa L.subsp.japonica)中花11构建的转座子突变体库,进行了水稻种子萌动期抗低温逆境突变体的筛选.以不同年份的种子为材料,在低温下观察种子的发芽率.结果表明,在低温下粳稻突变体(编号T108A5和T237b1)种子的发芽率比对照亲本中花11高出近50%,同一株系不同年份种子的两次发芽率具有相关性,说明这种筛选耐低温突变体的方法是可行的,在分子水平上的进一步检测正在进行中.     

大肠杆菌不耐热肠毒素(LT)突变体LTR72的表达与鉴定

将重组质粒PLTR72和PLT分别转化大肠杆菌JM101，DH5α和C600，并接种于LB和CAYE-2中培养，用GM1-ELISA法检测菌体裂解液中2者的表达情况，将表达产物纯化后用SDS-PAGE等方法鉴定。结果表明，3种大肠杆菌在2种培养基中都可表达出LT突变体和LT，并可将产物分泌到大肠杆菌胞周质中，成为具有GM1结合活性的突变体蛋白，鉴定纯化后的突变体的组成形式与野生型LT相同。均是1A：5B。     

Characterization of sequence-related amplified polymorphism markers analysis of tree peony bud sports

Bud sports have been widely exploited for creating novel cultivars in vegetatively propagated plants. However, bud sports of tree peony have rarely occurred nor been applied to breeding. We used sequence related amplified polymorphism (SRAP) markers to characterize two tree peony groups with bud sports. ‘Er Qiao’ and ‘Luo Yang Hong’ formed group I and are derived from Chinese cultivars, while ‘Shima-nishiki’ and ‘Taiyō’ formed group II and are related to Japanese cultivars. The DNA samples were evaluated with 25 different primer pairs. This resulted in a total of 149 different amplicons in Group I, of which 80.5% were polymorphic. Group II generated a total of 57 amplicons, of which 63.2% were polymorphic. The two groups shared 43 amplicons. The genetic similarity among the cultivars ranged from 0.33 to 0.60. The two bud sports groups were apparently separated on the unweighted pair-group method with arithmetic averages cluster analysis tree. The results demonstrated that this marker system appeared effective in detecting molecular differences between original parents and their bud sports in tree peony. This study provides a technical base for characterizing plants with bud sports, which are valuable genetic resources for further breeding.     

The effect of plant-associative bacteria (Azospirillum and Pantoea) on the fruit quality of sweet pepper under limited nitrogen supply

This study investigates the influence of a commercial product, Biopron^®, consisting of the bacteria Azospirillum brasilense and Pantoea dispersa on sweet pepper fruits (Capsicum annuum L.) under limited N supply. When the N supply was reduced from 12 (control) to 7 mmol L⁻¹, the concentration of total-N in the fruits was significantly reduced in both inoculated and non-inoculated plants. The N supply or inoculation did not affect the dry matter content or fruit firmness, but non-inoculated fruit with low N showed a decrease in pericarp thickness and a significant increase in the color parameter a^* compared with the control. Under limited N, inoculation increased the concentration of citric, ascorbic and succinic acids in green fruit compared with non-inoculated fruit, which showed lower values than control fruit. At a later (yellow) stage of development, only succinic acid showed a response to inoculation. Fruit peroxidase (EC 1.11.1.7) activity in fruit of inoculated plants was lower than that observed for non-inoculated fruit grown at both high- and low-N. In contrast, in yellow fruit, total phenolic compounds were increased under N limitation, with no inoculation effect. Our study shows that the effect of plant associative bacteria is not directly related with the increased potential availability of nutrients for uptake, especially for fruit quality characteristics.     

城市色彩设计的新思考

城市色彩直接反映城市的历史文脉和整体风貌,是城市特色与品位的重要标志,也是城市魅力的重要构成。然而,城市的色彩构成是多元的,是一个复杂而庞大的色彩系统。本文将针对目前城市色彩存在的问题,探讨城市色彩设计的意义和原则,将色彩有序地运用到城市设计中去。     

Sensitivity to fluopicolide of wild type isolates and biological characteristics of fluopicolide-resistant mutants in Pseudoperonospora cubensis

Cucurbit downy mildew caused by the oomycete pathogen Pseudoperonospora cubensis is a devastating disease that is distributed worldwide and affects cucumber in open fields and greenhouses. Fluopicolide, which was a novel systemic fungicide and was released in 2008, it is very effective in controlling downy mildew on cucumber and grape, potato late blight and pepper Phythophthora blight and reduces the loss caused by the diseases, but so far the potential for P. cubensis to develop resistance to fluopicolide has not been investigated. Hence, a laboratory study was undertaken to assess the risk of P. cubensis developing resistance to fluopicolide. Baseline sensitivity to fluopicolide was determined by using 75 P. cubensis isolates collected from cucumber-growing greenhouses in Hebei province, where no fluopicolide had been used for control of cucumber downy mildew before. Values of effective concentrations for 50% inhibition (EC₅₀) of sporulation ranged from 0.02 to 0.40 μg ml⁻¹ and were distributed as a unimodal curve, indicating that all 75 isolates were sensitive to fluopicolide. Sporangia of nine sensitive isolates were ultraviolet (UV)-irradiated, and four fluopicolide-resistant mutants were acquired at a mutation frequency of 7.4 × 10⁻⁷. Seven mutants resistant to fluopicolide were obtained from seven isolates by sporangia adaptation on fluopicolide-treated leaves of cucumber. The EC₅₀ values for all eleven fluopicolide-resistant mutants ranged from 3.37 to 13.06 μg ml⁻¹ with mean resistance factors of 7.9–118.0. After 10 sporangia transfers on fungicide-free leaves of cucumber, all eleven resistant mutants remained resistant to fluopicolide with mean resistance factors of 8.2–81.3. Seven resistant mutants from the selection for resistance and one resistant mutant from UV mutagenesis exhibited stable resistance; however, the other three resistant mutants from UV irradiation became significantly less resistant. Compared to their respective sensitive parents, the eleven resistant mutants exhibited diversity in latent period, infection frequency, lesion extension and sporulation ability. Five out of the eleven resistant mutants exhibited prolonged latent period and three out of the eleven resistant mutants provided decreased infection frequency (IF) compared to their respective parents, indicating that in some cases, resistance mutation might affect the latent period and IF of P. cubensis. There were significant differences in pathogenicity and ability to produce sporangia, but this seemed not to be caused by resistance mutation. No cross-resistance was detected between fluopicolide and azoxystrobin, metalaxyl, dimethomorph, or cymoxanil. In all, there could be a moderate to high risk of field populations of P. cubensis developing resistance to fluopicolide, and populations of P. cubensis should be monitored regularly for their shift of sensitivity over years of application.     

松材线虫病木快速检疫技术的研究

根据松材线虫病死木的化学成分中酸性物质增加，ｐＨ值明显下降的规律（尤纪雪等，１９９４），本研究探讨了利用指示剂在松材线虫Ｂｕｒｓａｐｈｅｌｅｎｃｈｕｓ ｘｙｌｏｐｈｉｌｕｓ（Ｓｔｅｉｎｅｒ Ｂｕｒｈｅｒ）Ｎｉｃｋｌｅ病、健木钻木屑的乙醇提取液中的颜色反应来进行快速检疫检验的可行性。通过对我国江苏、安徽、浙江、广东４个疫区的５种松树的试验结果表明：利用指示剂１号进行快速检疫检验，其准确率黑松９６％；马尾松８９％；赤松１００％；火炬松９２％。除湿地松（江苏）外，均已达到检疫检验所要求的准确程度。本方法可操作性强，颜色反应直观，准确率高，简便快速，整个操作过程不超过１５ｍｉｎ，且多个样品可同时进行。在松材线虫病的检疫检验工作中具有广泛应用的实用价值。