Influence of growing season and donor plant age on anther culture response of some pepper cultivars (Capsicum annuum L.)

The effects of growing season and donor plant age on anther culture in Capsicum were investigated. Pepper cultivars Kekova and Sera Demre 8 were grown under unheated greenhouse conditions in winter season and field conditions in summer season. Flower buds were collected and cultured in weekly intervals from November to May in winter and from April to December in summer. The results of this study indicated that anthers from these two pepper genotypes gave different embryogenic response to seasonal effects. Kekova cultivar gave the highest embryogenic yield in summer season while this was occurred in winter season for Sera Demre 8 cultivar. The results of the study revealed that the effect of donor plant age was also an important factor in anther culture of pepper. Since 4-month-old plants gave the highest embryo yield in both cultivars in each seasons, it is possible to say that anthers collected from old plants have sufficient embryogenic response when the optimum developmental stage is selected.     

草地螟寄生蝇寄生规律及控害作用研究

田间调查和室内饲养观察表明,康保县草地螟的寄生蝇主要有伞裙追寄蝇、双斑截尾寄蝇等5种。草地螟寄生蝇一般只寄生幼虫,未见寄生其他虫态。寄生率随草地螟幼虫密度增大、虫龄增长而迅速升高。多年发生资料分析,寄生蝇寄生率高的年份,下年草地螟的发生为害程度明显减轻。     

杀虫植物非洲山毛豆的研究

非洲山毛豆原产于热带非洲,是一种优异的杀虫植物。本文对其生物活性、杀虫有效成分、作用机理、加工使用等方面进行了概述。     

药用植物半夏细胞悬浮培养和植株再生体系建立研究

为了建立甘肃产药用植物半夏的细胞悬浮培养和植株再生体系,通过对其不同外质体筛选、愈伤组织诱导和悬浮培养的愈伤组织类型、激素水平、起始密度、震荡速率等影响因素以及细胞生长状态、生长曲线和pH值变化等指标的研究.结果表明:以叶柄为外质体,选择"松散型"愈伤组织和2×105个/mL的起始培养密度,在附加2,4-D 2.0 mg/L BA 0.5 mg/L NAA0.5 mg/L的1/2 MS培养基上培养,温度(23±2)℃,转速90 rpm,pH值6.0,黑暗培养为最适悬浮培养体系;经检测细胞生长曲线呈"S"型,培养液pH随着细胞的生长先上升后下降,18 d时细胞基数达到最大值;悬浮继代培养后,通过降低或停止震荡转速,在添加BA 0.5 mg/L NAA0.5 mg/L的MS液体和固体培养基上可诱导分化出芽和根,进一步形成完整的植株.     

毛茛科植物提取物添加量对瘤胃微生物体外动态发酵的影响

试验采用活体外产气量法研究毛茛科植物提取物不同添加水平对瘤胃微生物体外发酵的影响。试验采用单因子完全随机化试验设计,以小麦面粉为底物进行体外发酵。瘤胃液供体动物为3头装有永久性瘤胃瘘管的本地黄牛,日粮精料水平为30%(日饲喂2次)。植物提取物添加水平分别为0、100、200、300和400mg/L。结果表明:随着毛茛科植物提取物添加水平的提高,小麦面粉24h的DM消化率呈线性下降(P=0.0002),活体外产气速度呈二次曲线规律降低(P=0.0001),而产气延滞期线性增加(P=0.0001),理论最大产气量呈二次曲线规律增加(P=0.0001)。随着植物提取物添加水平的提高,发酵液pH值呈二次曲线增加(P<0.024)。各培养时间点乳酸含量均较低(P<1mmol/L),且各处理之间差异不显著(P>0.10)。提高植物提取物添加水平导致tVFA产量呈二次曲线趋势下降(P<0.01)。通过本试验可得出:毛茛科植物提取物可以通过降低瘤胃发酵的产气速度、提高发酵液pH值以及乙酸和丁酸摩尔比例来调控瘤胃微生物体外发酵,其中植物提取物的适宜添加水平为200～300mg/L。     

Cryopreservation of carnation (Dianthus caryophyllus L.) shoot tips by encapsulation-vitrification

Shoot tips excised from in vitro cultured plants of Dianthus caryophyllus L. (cv. Pallas, cv. Pink Candy and cv. Wanessa) were successfully cryopreserved using an encapsulation-vitrification method. Shoot tips (2–3 mm in length) were encapsulated in sodium alginate, precultured on liquid Murashige and Skoog (1962) medium supplemented with various sucrose concentrations (0.25, 0.5, 0.75, 1.0 M) for 24 h or 48 h and dehydrated with the vitrification solution PVS2 (up to 4 h) at 24 °C or 0 °C prior to direct immersion in liquid nitrogen (−196 °C). A maximum of shoot regeneration from cryopreserved shoot tips was obtained with the following combinations: preculture in 0.5 M sucrose and 180 min dehydration treatment at 0 °C for cv. Pallas (60% shoot formation), or preculture in 0.75 M and 200 min dehydration at the same temperature for cv. Pink Candy (66.6% shoot formation) and cv. Wanessa (73% shoot formation).     

Rooting response of shoot cuttings from three peach growth habits

Current year shoot cuttings were collected in October and August from three growth habits of peach (Compact, Pillar, and Standard) and treated with one of four concentrations of indole butyric acid (0, 250, 1250, and 2500 mg L⁻¹ IBA). Rooting response was measured after 5 weeks in the greenhouse. Little or no rooting occurred with cuttings from any growth habit that was collected in October or in August when treated with 0 and 2500 mg L⁻¹ IBA. In August, the number of shoots that rooted was greater in cuttings from Pillar (79 and 45%) than Compact (13 and 3%) treated with 250 and 1250 mg L⁻¹ IBA, respectively. Cuttings from Standard trees had intermediate rooting of 56 and 6% at 250 and 1250 mg L⁻¹ IBA, respectively. Pillar trees consistently grew more roots with greater root length per cutting than the other growth habits. It is proposed that differences in rooting response among the growth habits may be associated with differences in endogenous auxin concentration that had been found in previous studies. Within peach and possibly other fruit trees, the capacity of shoot cuttings to develop adventitious roots can vary by cultivar and successful root induction with exogenous plant growth regulators may depend, in part, on endogenous hormone levels.     

Introductions of non-native plant pathogens into Great Britain, 1970–2004

An analysis of records of plant pathogens first identified in Great Britain from 1970 to 2004 (inclusive) was undertaken to determine the numbers of new species that have become established over time. Results show that the numbers of newly recorded pathogens have not varied significantly. Of the 234 pathogens recorded for the first time between 1970 and 2004, 157 were fungi, 27 were oomycetes, 26 were viruses, 23 were bacteria, and one was a phytoplasma. Approximately 53% of pathogens were found on ornamental crops, 16% on horticultural crops, 15% on wild native species, 12% on agricultural crops, 2% on pasture plants and 2% on exotic forestry tree species. Where the origin of introductions was known or strongly suspected, 47% came from the Netherlands. About 38% of newly recorded pathogens with information on the location of first record were discovered in the South East region of England. Plant Pathologists regarded 19% of all new pathogens as important because of actual or potential economic/environmental losses. The results indicate that the numbers of new or important pathogens establishing in recent years are not increasing and that most new findings are associated with ornamental plants.     

Effects of loosing Aigamo ducks on the growth of rice plants, weeds, and the number of arthropods in paddy fields

Aigamo duck farming has been noticed as one of the techniques of environmental conservation agriculture. This study was carried out to investigate the effects of loosing Aigamo ducks on the growth and production of rice plants, the quantity of weeds and arthropods, and the balance of nitrogen (N) in paddy fields by changing the density of the Aigamo ducks. A paddy field was divided into three test plots: a 10-Aigamo-duck plot, a five-Aigamo-duck plot, and a weeding plot. The results show that the height, number of culms, and yield crops of the rice plants increased more in the 10-Aigamo-duck plot and the five-Aigamo-duck plot than that of the weeding plot. Millet ( Echinochloa oryzicola ) remained in both the Aigamo duck plots. The weeding plot was covered with monochoria ( Monochoria vaginalis ). In both the Aigamo duck plots, the outbreak of total arthropods was lower than that of the weeding plot, but the number of rice plants damaged by grass leaf rollers ( Cnaphalocrocis medinalis ) was increased. The number of spiders, regarded as useful insects, did not differ that much between the experimental plots. The N content of the soil did not differ as an effect of loosing the Aigamo ducks. The rice plants in the 10-Aigamo-duck plot absorbed more N than the rice plants in the other plots.