糯米糍荔枝果实内源激素与落果的关系

以糯米糍荔枝生理落果期的田间调查和胚胎发育研究为基础,探讨了内源激素与生理落果的关系.结果表明,糯米糍生理落果高峰的主要原因是:第1次因授粉受精不良导致的生长促进类激素尤其是CTK水平过低;第2次与胚乳为胚的发育所利用而消失、IAA和GAs急剧降低有关;第3次与胚的败育造成CTK、GAs和IAA的全面下降有关;第4次发生在假种皮(果肉)迅速生长期,与种皮和假种皮ABA升至高水平有关.此外,还探讨了ABA /(IAA+GAs+CTK)与生理落果的相关性,以及胚囊、珠被和假种皮等果实内部组分内源激素的变化特点.     

Identification of feline blood B and T lymphocytes by cell electrophoresis.

The electrokinetic properties of feline blood lymphocytes isolated by centrifugation over Ficoll-Isopaque gradient were investigated. A biphasic electrophoretic mobility (EPM) distribution was regularly observed with a low-mobility (LM) population (mean EPM: 0.82) accounting for 32% of blood lymphocytes and a high-mobility (HM) population (mean EPM: 1.09) representing 68% of blood lymphocytes. Following fractionation on nylon-wool columns, lymphocytes with B-cell properties (64% sIg⁺; 9% guinea pig erythrocytes (GPE)-rosette⁺, PHA and Con A unresponsive) were enriched in the adherent fraction and belonged mainly (78%) to the LM population. In contrast, lymphocytes with T properties (5% sIg⁺, 42% GPE-rosette⁺, PHA and Con A responsive) were recovered in the effluent fraction and comprised 84% of HM elements.Thus, in cat blood, LM lymphocytes are likely to represent in majority B cells and HM lymphocytes T cells. This indicates that cell electrophoresis provides an interesting mean for differentiating B and T cells in the cat.     

A method to test wheat leaves for their reactions to inoculation with Septoria species

The construction and application is described of a polystyrol humidity box in which wheat leaves, while continuing to function as parts of living plants, can be tested for their reactions toSeptoria spp. in an atmosphere nearly saturated with water, as is required for successful infection. The method is simple, accurate ans inexpensive.Samenvatting Voor dit doel is een z.g. vochtdoos geconstrueerd (Fig. 1A). Het te toetsen blad wordt daar doorheen geleid en in de doos geïnoculeerd met een druppel conidiën-suspensie van de schimmel. Onder het blad staat wat water in de doos (Fig. 1B). Na afsluiting ontstaat in de doos de hoge luchtvochtigheid van bijna 100% die nodig is voor de infectie. Dit wordt op deze wijze eenvoudig en goedkoop gerealiseerd. De bladeren die zo worden getoetst blijven onbeschadigd functioneren aan de plant. Na enkele dagen kan de doos worden geopend en kan de symptoom-ontwikkeling worden afgewacht en gevolgd (Fig. 3A, 3B en 4). De methode leent zich voor nauwkeurig werk en vereist zeer weinig infectiemateriaal. De Technische en Fysische Dienst voor de Landbouw (TFDL), Wageningen, ontwierp en construeerde een statief voor het gebruik van de vochtdozen in serie (Fig. 2).     

水稻苗田化学除草剂—封闭1号大面积苗田药效示范试验结果

通过多点水稻苗田大面积示范试验结果表明,通化市农科所研制的水稻苗田除草剂“封闭1号”具有除草效果好(90～100％)、安全、使用方便、成本低等特点。1988～1991年,累计推广面积(苗田)达15.6万亩,创造经济效益150万元。     

Bacterial diseases of potatoes: from classical phytobacteriology to molecular pathogenicity

Various bacterial pathogens attack potato plants and tubers. These pathogens includeErwinia, Corynebacterium (Clavibacter), Psuedomonas andStreptomyces. Over the past few years there have been significant advances in the molecular biological analysis of several of these pathogens and this is now helping us to understand the major aspects of virulence mechanisms. However, to date, such information is not sufficiently useful to allow us to intervene rationally in these potato diseases, except by the standard practises of good husbandry.     

Preliminary results of using in vitro axillary and adventitious buds in mutation breeding of Chinese gooseberry

Summary Aseptically cultured shoots of Chinese gooseberry exhibited growth disorder and morphological aberrances, and some died after being exposed to sufficient gamma-ray irradiation. The death rate was dose dependant and the LD₅₀ was 80–90 Gy and 50–60 Gy respectively for cv. Hayward and clone 4. All petiole explants irradiated with gamma-ray could form calli as the control, but the rate of differentiation of adventitious shoots of the petiole explants decreased and was dependant on dose. Sensitivity of the shoot or petiole explants to gamma-ray irradiation varied with species. Gamma-ray irradiation did not deter either the 2-node segments from producing axillary shoots M₁, M₂, and M₃ or the advantitious shoots originating in the petiole explants and the M₃ shoots from forming advantitious roots. Therefore, using aseptically cultured axillary or adventitious buds for mutation breeding of Chinese gooseberry is feasible. A bacterium surviving in the explants lessened the efficiency of these two in vitro techniques in mutation breeding of Chinese gooseberry.Abbreviations IAA 3-indole acetic acid - IBA -indole butyric acid - MS Murashige & Skoog (1962)     

ONCHOCERCA GUTTUROSA IN Danish cattle. Prevalence, geographic distribution and host-vector relationships.

1. Onchocerca gutturosa is reported in Danish cattle for the first time. Microfilariae were found in 38 (9.4%) of 406 cows that were 2 years or older.
2. Microfilariae were not randomly distributed throughout the skin but were concentrated in the umbilical area.
3. No difference in prevalence was observed between breeds of cattle.
4. Most of the infected cows had grazed on fields close to streams that contained Simulium ornatum, the vector of O. gutturosa.
5. Differences in preferred biting sites of S. ornatum from cow to cow were correlated with the arrangement of hair.

     

自由放养下绵羊的营养参数

根据绵羊的营养参数和饲养标准,结合日增重水平,计算了不同日增重水平对应的体重月平均动态及其所对应的粗蛋白日需要量和代谢能日需要量。不同日增重水平,达到生长期望所需要的日数不同,日增重水平越高,达到生长期望总所需要的粗蛋白和代谢能越少,但月平均的日需要量越多。自由放养的东北细毛羊当年生羔羊的日增重水平仅相当于舍饲饲养日增重的100g水平,根据代谢能计算,年总需干草340kg,可以作为计算载畜量的基本参数。自由放养情况下,即使能量满足需要,粗蛋白也短缺。当年生羔羊日增重在150￣200g,9￣10月龄内体重达到46￣50kg是北方草地家畜生产的理想目标,通过补饲可以实现。     

利用芥蓝×青花菜DH群体构建AFLP连锁图谱

 利用青花菜(Brassica oleracea var. italica) 与芥蓝(Brassica oleracea var. alboglabra) 杂交后代双单倍体(DH) 群体为材料, 通过AFLP技术构建了一个甘蓝类作物较高密度的遗传连锁图谱。该图谱包括9个主要连锁群及2个小连锁群, 总图距801.5 cM, 含337个AFLP标记, 标记间平均距离为3.6 cM,为甘蓝类作物基因定位、比较基因组学及重要经济性状QTL分析提供了一个框架图谱。