茄子早熟育种研究Ⅱ选择指数与早熟性选择

研究结果表明,由性状果实最大周长,果实体积,门茄显蕾期,单株产量等性状构成的选择指数较好;进一步进行遗传相关分析结果认为,应用选择指数时应注意果实体积这个性状,单株产量是一个重要的辅助性状,门茄显蕾期是一个限制性因子。应用选择指数对品种评价结果认为,早熟性较好的品种有:天津早茄、西安绿茄、二民、七叶茄、白线茄和汉中荷包。     

柑橘属2n花粉自然发生与沙由柚2n花粉诱导研究

果树2n配子育种较其他植物起步晚，尤其是利用2n花粉进行育种的研究在柑橘上还无先例。试验中初步观察了柑橘属部分品种的2n花粉自然发生情况，证实了柑橘属内未减数花粉的存在。同时通过秋水仙碱不同浓度与作用时间处理促进了柑橘2n花粉的发生，将长寿沙田柚2n花粉发生比例由当年的自然发生率0．87％提高到9.76％。初步观察了2n花粉离体萌发状况，其萌发率与花粉管伸长速度较为正常，但萌发启动比单倍性花粉慢。     

小麦品种抗病性的ELECTRE法决策与应用软件

 用ELECTRE-I决策法评价若干小麦品种的抗赤霉病性,筛选出部分较好的原始材料。结果证明该方法精确性高,适用而广,在农业领域的多种评价研究中有重要应用价值。建议用主成分分析结果中的贡献率判定目标权重,为择权过程提供了一种实用方法。     

Effect of aluminum on callose synthesis in root tips of tea (Camellia sinensis L.) plants

Aluminum (Al) toxicity is a major factor limiting yield production on acid soils (Foy 1983). The initial symptom of Al toxicity in many plants is manifested by the inhibition of root elongation (Ownby and Popham 1990; Llugany et al. 1994; Sasaki et al. 1994; Horst et al. 1997), which occurs during a very short period of time after exposure to Al (Llugany et al. 1994; Staß and Horst 1995). In a large number of recent reports, it was shown that the root apex plays a major role in the Al-sensitivity and response mechanisms (Zhang et al. 1994; Sasaki et al. 1997; Sivaguru and Horst 1998). However, it is interesting to note that stimulatory effects of Al on the growth of plants have also been reported in some studies (Chenery 1955; Konishi et al. 1985; Huang and Bachelard 1993; Osaki et al. 1997). In tea plant (Camellia sinensis L.) a stimulatory effect of Al on the growth was also demonstrated in some experiments, using intact plant (Chenery 1955; Konishi et al. 1985), cultured roots (Tsuji et al. 1994), and pollen tubes (Yokota et al. 1997). The growth of tea roots was typically more stimulated than that of shoots by Al (Konishi et al. 1985). It was assumed that Al effects might be due to the amelioration of phosphorus absorption (Konishi et al. 1985), secretion of malic acid from roots to dissolve aluminum phosphate in the rhizosphere (Jayman and Sivasubramaniam 1975), stimulation of growth of microorganisms on the root surface (Konishi 1990) or replacement of some functions of boron (Konishi 1992; Yokota et al. 1997). However, the stimulatory effects of Al on tea plant growth have not yet been el ucidated.

The formation of callose (1,3-β-glucan) has been reported as a common plant response to a variety of stresses, as well as mechanical, biophysical, chemical, and biological injury (Jaffe and Leopold 1984; Zhang et al. 1994). Increased synthesis of callose has been observed upon exposure to excess amounts of some elements, such as boron (McNairn and Currier 1965), cobalt, nickel, zinc (Peterson and Rauser 1979), and manganese (Wissemeier and Horst} 1987, 1992). Callose synthesis was also induced by Al in the roots of Triticum aestivum (Zhang et al. 1994) and Zea mays (Horst et al. 1997; Sivaguru and Horst 1998), suspension-cultured cells of Glycine max (Staß and Horst 1995), and protoplasts of Avena sativa (Schaeffer and Walton 1990) and Zea mays (Wagatsuma et al. 1995). Induction of callose synthesis in roots seems to be a very rapid physiological indicator of Al-induced injury or genotypical differences in Al sensitivity (Wissemeier and Horst 1992; Zhang et al. 1994; Horst et al. 1997). Nevertheless, Al-induced callose synthesis in tea plant, whose growth is stimulated by suitable Al concentrations, has not been described yet. Therefore, to elucidate the physiological basic effects of Al on tea plant, callose synthesis affected by Al in the root tips of intact plants was analyzed in the present study.     

Effect of flutianil on the morphology and gene expression of powdery mildew

Flutianil, a fungicide effective only on powdery mildew, was previously reported to affect the host cell''s haustorial formation and nutrient absorption. Studies were conducted to investigate flutianil''s primary site of action on Blumeria graminis morphology using transmission electron microscope (TEM) observation and RNA sequencing (RAN-seq) techniques. TEM observation revealed that flutianil caused the extra-haustorial matrix and fungal cell wall to be obscured, without remarkable changes of other fungal organelles. RNA-seq analysis indicated that, unlike other powdery-mildew fungicides, flutianil did not significantly affect the constantly expressed genes for the survival of B. graminis. Genes whose expression is up- or downregulated by flutianil were found; these are the three sugar transporter genes and various effector genes, mainly expressed in haustoria. These findings indicate that the primary site of action of flutianil might be in the haustoria.     

北京地区规模化奶牛场牛病毒性腹泻病血清学调查

对北京郊区6个未进行牛病毒性腹泻病（BVD）免疫牛场的546份奶牛血清样品,使用牛病毒性腹泻抗体ELISA试剂盒进行检测,并对其中3个牛群进行牛病毒性腹泻病毒（BVDV）血清抗原筛查。共检出阳性血清514份,总阳性率94.1%,其中5个牛场的场内血清抗体阳性率在95%以上。牛病毒性腹泻持续性感染牛（PI牛）筛查的3个牛群均有阳性牛检出。结果表明,北京地区规模化奶牛场存在牛病毒性腹泻感染和接触史,应采取净化措施进行控制。     

Academic tenure and mandatory retirement under the new law

Federal abrogation of the age-based mandatory retirement provisions in existing academic tenure contracts calls for a review of tenure and salary policies. Here two alternative explanations for the institution of tenure are examined. Then five alternative policy responses that might be adopted by university administrations are described and analyzed. The proposal favored by the author consists of a two-track salary plan in which a distinction is drawn between tenure and employment.     

Chemical composition of an East African traditional beverage, togwa

Togwa is a starch-saccharified nonalcoholic traditional beverage consumed in sub-Saharan Africa. In the southern part of Tanzania, togwa is usually made from maize flour and finger millet malt. In this region, togwa is consumed by working people and also used as a refreshment as well as a weaning food. Togwa was prepared in the laboratory using a specific reactor and analyzed for its general chemical composition in both laboratory and field forms. From the analysis of the trace elements and amino acid contents in togwa and its materials, it has been clarified that togwa contains many kinds and a high quantity of minerals derived from finger millet malt. It was concluded that togwa should be nourishment and a major source of minerals as nutrients for the inhabitants of this region.     

湖北省地衣1个新记录属和3个新记录种

通过对后河国家级自然保护区地衣资源进行调查,发现湖北省地衣1个新记录属,即癞屑衣属,对应3个湖北省地衣新记录种,分别为膜癞屑衣、灰白癞屑衣、淡蓝癞屑衣并对其形态特征进行了简要描述,为湖北省地衣资源研究和利用提供新资料。     

Metabolic conversion of dietary quercetin from its conjugate to active aglycone following the induction of hepatocarcinogenesis in fisher 344 rats

Quercetin exhibits a potent anticarcinogenic activity. However, ingested quercetin circulates as the glucuronide/sulfate conjugates, which are less active compared to the aglycone in healthy individuals. This study aimed to develop further understandings of the cancer-preventing mechanism with dietary quercetin. According to a two-stage hepatocarcinogenesis model with N-diethylnitrosamine (DEN) and phenobarbital (PB), preneoplasms were induced specifically in the liver of Fisher 344 rats. In the liver, glutathione S-transferase placental form (GST-P) positive foci were produced 14 weeks later. beta-Glucuronidase activity increased significantly in the liver by 1.2-fold in the DEN/PB group compared to the activity in a saline group. In the kidney, thymus, lung, heart, and plasma, the activities were similar between both groups. When quercetin was dosed intragastrically 15 min before sacrifice, the aglycone level of quercetin in liver was significantly 1.9-fold higher in the DEN/PB group than in the saline group. On the other hand, quercetin was dosed to rats 3 times a week for 14 weeks. The treatment kept the aglycone level of quercetin at a significantly higher level and tended to suppress the formation of GST-P positive foci. The increase in beta-glucuronidase activity with carcinogenesis induction became insignificant following the frequent doses of quercetin. It was considered that quercetin aglycone played a preventative role and, thus, the conjugates were converted to the active aglycone by beta-glucuronidase that was induced by the generation of preneoplasms.