不同继代培养次数对苹果八棱海棠离体培养和遗传转化的影响

以苹果八棱海棠离体新梢和幼叶为外植体,研究不同继代次数对其离体繁殖、再生和遗传转化的影响。结果表明,随着继代培养次数的增加,继代10次和48次的八棱海棠离体增殖倍数、生根能力、不定芽的再生频率、每外植体再生芽数和GUS基因瞬时表达率均显著高于继代5次的;继代10次的增殖倍数和GUS阳性率明显多于继代48次的,其它指标相互间差异不显著;说明继代10次的芽苗较适合用于八棱海棠离体培养的外殖体材料,其幼叶较适于遗传转化研究。     

In Vitro propagation of juvenileNothofagus leoni Espinosa (Fagaceae)

Nothofagus leoni has a restricted distribution in Chilean forests. This work determines suitable culture conditions forin vitro multiplication and rooting through shoots obtained from seedlings. Broadleaved Tree Medium was suitable for shoot multiplication. A medium with a pulse of 0.55 μM BA in the first subculture and two subcultures on BA-free medium resulted in a multiplication rate at day 63 of × 5.7, without callus growth or shoot neoformation. Rooted shoots of good quality (number and length of roots without callus growth) were obtained with 1.23 μM IBA (91.4% of rooting). The first roots appeared at day 11, reaching a higher speed of rooting at day 15.     

松毛虫质型多角体病毒围栏增殖技术

病毒围栏增殖方法由云南省林科院经过１０多年病毒复制试验证明：该方法是增殖ＣＰＶ用以防治松毛虫最经济实用的方法。其病毒投入少,产量高,风险较小。设置围栏采集６～７龄文山松毛虫幼虫,选用１×１０７ＣＰＢ／ｍＬ的病毒感染浓度,接种后１３～１５天回收,感病虫回收率可达８０％以上,单虫多角体病毒含量达２０亿以上。本文详细介绍了围栏制作,增殖场地选择,围栏管理,最适病毒感染浓度及感病虫的回收时间和采集增殖病毒幼虫的方法。     

A rapid multiplication system for ‘Candidatus Liberibacter asiaticus’ through regeneration of axillary buds in vitro

‘Candidatus Liberibacter asiaticus (CLas)’, which causes citrus Huanglongbing (HLB) disease, has not been successfully cultured in vitro to date. Here, a rapid multiplication system for CLas was established through in vitro regeneration of axillary buds from CLas-infected ‘Changyecheng’ sweet orange (Citrus sinensis Osbeck). Stem segments with a single axillary bud were cultured in vitro to allow CLas to multiply in the regenerating axillary buds. A high CLas titer was detected in the regenerated shoots on an optimized medium at 30 days after germination (DAG). This titer was 28.2-fold higher than in the midribs from CLas-infected trees growing in the greenhouse. To minimize contamination during in vitro regeneration, CLas-infected axillary buds were micrografted onto seedlings of ‘Changyecheng’ sweet orange and cultured in a liquid medium. In this culture, the titers of CLas in regenerated shoots rapidly increased from 7.5×10⁴ to 1.4×10⁸ cells μg^–1 of citrus DNA during the first 40 DAG. The percentages of shoots with >1×10⁸ CLas cells μg^–1 DNA were 30 and 40% at 30 and 40 DAG, respectively. Direct tissue blot immunoassay (DTBIA) indicated that the distribution of CLas was much more uniform in regenerated plantlets than in CLas-infected trees growing in the greenhouse. The disease symptoms in the plantlets were die-back, stunted growth, leaf necrosis/yellowing, and defoliation. The death rate of the plantlets was 82.0% at 60 DAG. Our results show that CLas can effectively multiply in citrus plantlests in vitro. This method will be useful for studying plant-HLB interactions and for rapid screening of therapeutic compounds against CLas in citrus.     

百合试管苗快速繁殖技术的研究

对百合鳞片进行了试管快速繁殖研究．结果表明：外植体取样部位影响百合小鳞茎的增殖率,幼嫩的基部增殖率高,而外部、顶部细胞老化的鳞片增殖率低．百合小鳞茎的形成主要靠不定芽的形成．     

青蛤增养殖技术研究及开发

利用盐场原有设施进行青蛤增养殖技术研究,并对青蛤生长,幼苗放养季节,规格,密度等做了系统研究。增殖试验在一号水库内进行,分两个试验区,３８２．６公顷为资源繁殖保护区;８４．１公顷为移苗增殖区,经过二年多实施,资源繁殖保护区资源量将增９．１倍,净增９５９．３吨;移苗增殖区资源量净增８．７倍,净增资源量２７０．７吨,总效益７３２万元。     

Disease eradication and propagation of the initial seed potato material in Estonia

Summary The EVIKA Research Centre has developed a disease eradication system for the initial material of seed potato, which consists of 1. Selection of the initial material for eradication, plant thermotherapy, meristem tip cultivation and testing for viruses; 2. Re-eradication (thermotherapy of test-tube plants, cultivation of meristem tips, testing for viruses, testing of varietal quality and yield of disease-free meristem clones, and the selection of meristem clones with best varietal characteristics; 3. Renewing of the initial material (all processes as above, but the initial material is selected from the seed potatoes grown for at least 3 years in the field). Field trials were conducted after the second cycle of eradiaction to determine whether the plantlets were true-to-type and to assess the yield, disease resistance and tuber dry matter. Recently we have also started in vitro testing of meristem plants resistance to late blight, hoping that this approach will improve the selection efficiency. Propagation and growing of the seed tubers consists of 3 main steps: 1. Plantlet propagation in vitro; 2. Greenhouse propagation in plastic rolls; and 3. Planting the first generation tubers in the field. Under our conditions it is the cheapest, simplest and most effective way. Multiplication of the meristem-derived plants is done by shoot tip cuttings in a greenhouse in plastic rolls with peat as the growing medium. The first generation of seed tubers is grown in the field. In our trials plant productivity was affected by the method of multiplication, growing conditions and genotype. The highest yield per hectare was obtained with plants multiplied in plastic rolls. The in vitro plants had more tubers per plant than plants multiplied in plastic rolls. In seed production fields the productivity of plants was more influenced by following our instructions than by multiplication and growing methods. The number of tubers per plant obtained with over 0.5 million plants was 6.5–9.0. In the second generation of seed tubers, grown under equal density, the greater-sized tubers gave more tubers with lower weight than the smaller-sized tubers. Cutting tubers had no effect on the plant development and tuberization.     

第八师奶牛养殖产业现状及政策建议

八师奶牛养殖优势突出,已形成以奶牛养殖为基础、乳制品加工为支撑的“养-加-销”于一体的产业链条,掌握师市规模化奶牛场的生产、管理和发展现状。通过加强政策支持和技术服务支撑,提高繁育水平,降低饲养成本。助力师市奶牛养殖扩繁增量突破10万头的目标。     

西伯利亚花楸组培苗增殖扩繁培养

该试验采用不同的培养基配方针对西伯利亚花楸组培苗进行扩大培养,以得出最佳扩 繁培养基配方,结果表明:MS+6-BA 0.5 mg/L+NAA 0.12 mg/L+IBA 0.05 mg/L+GA3 1.0mg/L 配方最有利于西伯利亚花楸组培苗的扩繁。     

Thermal requirements and population dynamics of root‐knot nematodes on cucumber and yield losses under protected cultivation

Several studies were carried out to determine (i) thermal requirements for development, egg production and emergence of juveniles, and completion of the life cycle of Meloidogyne incognita and Meloidogyne javanica on cucumber, (ii) the maximum multiplication rate and the equilibrium density of root‐knot nematodes on cucumber and yield losses in pot and plastic greenhouse experiments, and (iii) the relationships between relative leaf chlorophyll content (RLCC) and relative cucumber dry top weight biomass (RDTWB) in relation to increasing nematode densities at planting (P_i) in pot experiments. Thermal requirements of M. incognita and M. javanica on cucumber did not differ, irrespective of the biological stage. In the pot experiments, M. javanica completed one generation. The maximum multiplication rate (a) was 833, and the equilibrium density (E) varied according to the effective inoculum densities. The relationship between RDTWB and P_i fitted the Seinhorst damage function model. The RLCC value at 40 or 50 days post‐inoculation also fitted the damage model and was related to RDTWB. In greenhouse experiments, conducted from 2009 to 2012, M. incognita completed three generations. The values for a and E were 1147 and 625 second stage juveniles (J2) per 250 cm³ soil, respectively. The tolerance limit was below zero, and the minimum relative yield ranged from 0·12 to 0·34.