实时荧光定量PCR定量检测山核桃干腐病病菌潜伏侵染量方法的建立

由茶麋子葡萄座腔菌Botryosphaeria dothidea引起的山核桃Carya cathayensis干腐病是山核桃栽培过程中的主要病害,该病菌表现明显的潜伏侵染特性。研究山核桃树体中干腐病菌的定量检测技术对山核桃干腐病的预测预报及科学防治具有重要的指导意义。根据茶麋子葡萄座腔菌的EF1基因设计特异性引物,通过普通聚合酶链式反应（PCR）和实时荧光定量PCR（real-time PCR）扩增发现引物EFRT-F1/R1对山核桃干腐病病菌的特异性及扩增效率较高,可稳定扩增出230 bp的目标条带。应用此特异性引物建立的实时荧光定量PCR干腐病病菌检测方法能够定量检测出山核桃植株样品中的病菌含量,灵敏度要比普通PCR高100倍。图6参8     

Regeneration and transformation system in Mirabilis jalapa

Protocols for in vitro regeneration and production of in vitro-propagated plants and a transformation system were developed for Mirabilis jalapa (Nyctaginaceae). Among the types of explants and the different media tested, consistent shoot regeneration was obtained only from nodal segments grown in a regeneration medium consisting of Murshashige and Skoog medium supplemented with 2 mg l⁻¹ 6-benzyladenine, 2 mg l⁻¹ zeatin and 1 mg l⁻¹ indole acetic acid. Regeneration efficiency was dependent on the type of plant – white or pink flowers – used as the source of explants. Stable transformation was obtained following inoculation of nodal segments with Agrobacterium tumefasciens strain EHA105, which harbours the binary plasmid pAD1339 containing both nptII and gus genes under the control of the 35S promoter. Transformation was confirmed by PCR and Southern blot analysis of genomic DNA from mature regenerated plants. β-Glucuronidase (GUS) activity was observed only in tissues regenerated from in vitro-grown plants and not in tissues originating from greenhouse-grown plants. GUS expression was not uniform in regenerated leaves and showed a chimera pattern.     

海拔和密度对兰州百合产量的影响

在兰州市七里河区西果园镇和魏岭乡的3个不同海拔梯度研究了种植密度对兰州百合产量的影响.结果表明,百合出苗率只与海拔高度有关,与种植密度无关;海拔高度与百合的生物学性状呈负相关;种植密度与百合株高和叶片数呈负相关,而随种植密度的增加,单株重和种球周径均表现为先增加后减小的趋势.由效应方程可得,兰州百合最佳种植密度海拔22...     

Selection of food items for inclusion in a newly developed food-frequency questionnaire

OBJECTIVES: To highlight the differences between the food list required in a food-frequency questionnaire (FFQ) to rank people by their intake and the food items that contribute to absolute intake, and to discuss possible applications. METHODS: We conducted a nutritional survey among 1173 adults using an adapted 24-hour recall questionnaire. STATISTICAL ANALYSIS: To develop an FFQ, we analysed the 24-hour recall survey data by performing a stepwise multiple regression after grouping conceptually similar food items into 175 food groups. RESULTS: In total, 126 food groups were included in the developed FFQ in order to explain at least 80% of the variance in the consumption of each of 27 nutrients. The nutrients that were explained by a few food groups were vitamin A (one food group), alcohol (two), beta-carotene (two), vitamin E (three) and cholesterol (five). Nutrients that were explained by a large number of food groups were energy (37 food groups), potassium (31), magnesium (31), dietary fibre (30), phosphorus (31) and sodium (29). Using energy intake as an example, soft drinks were the best between-person energy classifiers, while providing only 2.4% of the total energy intake. Wine, seeds and nuts, which contributed highly to the variance, were minor energy contributors. In contrast, milk, sugar, fried chicken/turkey breast or whole chicken/turkey, which explained little of the variation in the population, were major energy contributors. CONCLUSIONS: Developing an FFQ on the basis of common foods may not explain the between-person variation required for ranking individual intake in diet-disease studies. Producing lists of "discriminating items" can be a useful application in developing mini-FFQs for selected nutrients.     

Effect of Phytohormones on Adventitious Bud Differentiation from Bulb Scales of Oriental Lily Test-tube Plantlets

[Objective] The purpose of this study is to investigate the effects of differ- ent phytohormones on the adventitious bud differentiation of oriental lily. [Method] The bulb scales of the test-tube plantlets of Tiber, Rodina and Constanta were cul- tured in media supplemented with different cytokinin and auxin at different concen- tration, and then the adventitious buds in each treatment were calculated. [Result] Cytokinins had different influence on the adventitious bud differentiation of the three oriental lily cultivars. Among them, 6-BA had the best effect to induce the adventi- tious bud differentiation from bulb scales of Tiber and Rodina, but there was some difference in the optimal concentration. KT had the best effect to induce the adven- titious bud differentiation of Constanta. The auxins had little influence on the quality of the adventitious bud of the three oriental lily cultivars, but caused some difference in differentiation coefficients. [Conclusion] The most suitable media for the adventi- tious bud differentiation from bulb scales in vitro of Tiber, Rodina and Constanta were MS＋0.2 mg/L 6-BA＋0.2 mg/L 2,4-D, MS＋I.0 mg/L 6-BA＋0.2 mg/L IAA, MS＋ 1.0 mg/L KT＋0.5 mg/L 2,4-D, respectively.     

Effects of salinity on the nail-holding power of dimension lumber used in light-frame wood building

We studied the effect of salinity on nail-hold-ing power in wood construction. In saline solution, the holding power of nails was less than in purified water. With the increase of salt concentration, t...