Effect of lucerne saponins and Lotus condensed tannins on survival of grass grub,Costelytra zealandica

Abstract

Crude extracts of lucerne (Medicago sativa) and Lotus pedunculatus root were toxic when administered orally to third-instar Costelytra zealandica larvae. Purified saponins from lucerne root were alone found sufficiently toxic to account fully for the activity of the crude extract. Condensed tannins extracted from L. pedunculatus and L. corniculatus had no effect on larval survival when administered at levels equivalent to those present in crude extracts.     

Characterization of transgenic root cultures of Trifolium repens, Trifolium pratense and Lotus corniculatus and transgenic plants of Lotus corniculatus

Hairy root cultures of three species of legume, Lotus corniculatus, Trifolium repens and T. pratense were established using a wild-type strain (C58C1 with pRi 15834) of Agrobacterium rhizogenes. Southern hybridization analysis confirmed that the lines were genetically transformed. Copy numbers of TL-DNA in different lines varied from one to eight. Examination of the transformed root cultures revealed changes in anatomy, morphology and cytology. Plants that had regenerated from hairy roots of L. corniculatus showed changes in morphology, physiology and cytology but no change in several parameters of nitrogen fixation activity.     

Can we use photography to estimate radiation interception by a crop canopy?

Accuracy of determining radiation interception, and hence radiation use efficiency, depends on the method of measuring photosynthetically active radiation intercepted. Methods vary, from expensive instruments such as Sunfleck ceptometers to simple methods such as digital photography. However, before universal use of digital photography there is need to determine its reliability and compare it with conventional, but expensive, methods. In a series of experiments at Lincoln, New Zealand, canopy development for barley, wheat, white clover and four forage brassica species was determined using both digital photographs and Sunfleck ceptometer. Values obtained were used to calculate conversion coefficient (Kf/Ki) ratios between the two methods. Digital photographs were taken at 45° and 90° for barley, wheat and white clover and at only 90° for brassicas. There was an interaction of effects of crop and cultivar for the cereal crops. Barley closed canopies earlier than wheat, and ‘Emir’ barley and ‘Stettler’ wheat had consistently higher canopy cover than ‘Golden Promise’ and ‘HY459′, respectively. Canopy cover was consistently larger at 45° than 90° for cereals. However, for white clover, the angle of digital photography was not important. There was also an interaction between effects of species and method of determining canopy cover for brassicas. Photographs gave higher cover values than ceptometer for forage rape and turnip, but the relationship was variable for forage kale and swede. Kf/Ki ratios of 1.0–1.10 for cereals, white clover and forage rape and turnip show that digital photographs can be used to estimated radiation interception, in place of Sunfleck ceptometer, for these crops.     

Different strategies of Lotus japonicus, L. corniculatus and L. tenuis to deal with complete submergence at seedling stage

Two main strategies allow plants to deal with submergence: (i) escape from below water by means of shoot elongation, or (ii) remaining quiescent under the water until water subsides and then resume growth. We investigated these strategies in seedlings of Lotus japonicus, L. corniculatus and L. tenuis subjected to control and submergence for 12 days, with a subsequent 30-day recovery period. All three species survived submergence but used different strategies. Submerged seedlings of L. japonicus exhibited an escape strategy (emerging from water) as a result of preferential carbon allocation towards shoot mass and lengthening, in detriment to root growth. In contrast, seedlings of L. corniculatus and L. tenuis became quiescent, with no biomass accumulation, no new unfolding of leaves and no shoot elongation. Upon de-submergence, seedlings of L. japonicus had the lowest recovery growth (a biomass and shoot height 58% and 40% less than controls, respectively), L. corniculatus was intermediate and L. tenuis showed the greatest recovery growth. Previously submerged seedlings of L. tenuis did not differ from their controls, either in final shoot biomass or shoot height. Thus, for the studied species, quiescence appears to be an adequate strategy for tolerance of short-term (i.e., 12 days) complete submergence, being consistent with field observations of L. tenuis colonisation of flood-prone environments.     

贵州野生越桔种质资源及其开发利用

通过实地调查,并查阅相关文献,概述了贵州野生越桔种类、分布与生境及其资源利用情况,并对贵州野生越桔资源的开发提出建议。     

Development of a ploidy series from a single interspecific Trifolium repens L.Ā . nigrescens Viv. F1 hybrid

 The objective of the current research was to generate a ploidy series of backcross progenies from a single triploid (2n=3x=24) Trifolium repens×T. nigrescens F₁ hybrid (3x H-6909-5). The 3x H-6909-5 plant was highly sterile and produced no seeds from approximately 3000 reciprocal backcrosses to both parental species. Chromosome doubling by an in vitro colchicine method resulted in a marked increase in fertility. Pollen stainability was increased from 9.9% in 3x H-6909-5 to an average of 89.2% (range 87.7–90.9%) in the three chromosome-doubled 6x H-6909-5 plants. Subsequent backcrosses of 6x H-6909-5 and interbreeding of backcross derivatives resulted in an array of fertile hybrids at 4x, 5x and 7x levels and some aneuploids. The occurrence of 7x BC₁F₁ progeny from the T. repens×6x H-6909-5 (4x×6x) cross is the first unequivocal evidence of functional female 2n gametes in white clover. Meiotic pairing in F₁ and BC₁F₁ progeny indicated the presence of allosyndetic pairing, suggesting that genetic exchange between the two species is possible. Received: 17 October 1996 / Accepted: 8 November 1996     

四个齿爪鳃金龟类群分类地位的RAPD分析

本应用RAPD技术对齿爪鳃金龟属（Holotrichia)的四个类群进行了分类地位的研究,结果表明,不同类群间的平均遗传距离分别为：华北大黑鳃金龟的登种群与南京种群间为0．346,登种群与东北大黑锶金龟间为0．375,南京种群与东北大黑鳃金龟间为0．359,矮臂锶金龟与登种群,南京种群和东北大黑鳃金龟间分别为0．552,0．545和0．534。对RAPD指纹图谱进行UPGMA聚类分析,系统发育树将以上四个类群分为了差异显的两大类,综合各项研究指标,东北大黑鳃金龟与华北大黑鳃金龟之间的差异为种群水平的变化,东北大黑鳃金龟与华北大黑鳃金龟属同种昆虫,按照动物命名法规,东北大黑鳃金龟应为华北大黑鳃金龟的同物异名。     

Sources of resistance to stem nematode, Ditylenchus dipsaci (Kühn) Filipjev, in species of Medicago and Trifolium

The putatively resistant lucerne cv. Euver was as susceptible to 11 English and 11 French populations of ‘lucerne race’ stem nematode, Ditylenchus dipsaci, as the susceptible cv. Europe. The ‘resistant’ cv. Vertus showed some resistance to five of the English and four of the French populations but was just as susceptible as Europe to three English and four French populations. Twelve annual species of Medicago were very resistant to a mixture of two English and two French populations of the nematode. None of 13 perennial spp. of Medicago was very resistant to the same mixture of nematodes but resistant plants were identified in M. borealis, M. dzhawakhetica, M. glutinosa and M. romanica. Twenty six spp. of Trifolium were resistant to a mixture of two English and two French populations of ‘red clover race’ stem nematode.     

Meiotic abnormalities underlying pollen sterility in wild potato hybrids and spontaneous populations

Wild potato species are widely distributed in the Americas, where they spontaneously grow in very diverse habitats. These species - with low chromosome differentiation - form polyploid series with 2n = 2x, 3x, 4x and 6x (x =12). They are isolated in nature by external and internal hybridisation barriers that can be incomplete, allowing hybridisation in areas of sympatry. Nevertheless, most accessions in germplasm banks, regardless of genetic background of the sampled spontaneous populations, have been assigned specific categories based on morphological characters. To further investigate the extent of hybridisation in the group and for comparative purposes, pollen viability was estimated in (i) artificial hybrids between a commercial cultivar (Calén INTA) of the common potato (tetraploid Solanum tuberosum ssp. tuberosum) and the tetraploid cytotype of the related wild species S. gourlayi, and (ii) samples of plants (accessions) and inflorescences of natural populations from Argentina, tentatively classified as 'presumed hybrids' (S. infundibuliforme-S. gourlayi) and 'species' (S. infundibuliforme, S. gourlayi and S. chacoense). Regardless of origin, 98 out of 103 plants analysed had zero to 70% pollen viability (zero to 40% in eight of them). Pollen grains were of variable size and morphology and, in mostly male sterile plants, the only viable pollen grains were 2n and/or 4n. Furthermore, male sterile plants shared various abnormalities in meiosis I and II (unpaired chromosomes, unequal chromosome distribution, precocious/lagging chromosomes, parallel, tripolar, fused and multiple spindles, unequal size nuclei, dyads, triads and pentads in addition to normal tetrads, among others). These results provide novel evidence to support field observations of early potato botanists on the extent of spontaneous hybridisation in wild Argentinian potato populations, which is not reflected in the current taxonomy and has significant consequences for germplasm conservation and breeding.     

The comparative phosphorus requirements of some temperate perennial legumes

The phosphorus (P) responses of seven temperate perennial pasture legumes and two species of lupins were compared in a field trial over a range of nine P rates, from 0 to 800 kg ha^-1. The two lupins produced more than 5 t ha^-1 of dry matter in the absence of added P and showed no response to the fertiliser. In contrast, the pasture legumes initially failed to grow without added P and responded to applications of between 200 and 800 kg ha^-1. At the higher rates of P, dry matter production of the pasture legumes was equivalent to that of the lupins.In the first 2 years of the trial; the most productive pasture legume species at the higher rates of added P were also the most productive at the lower rates. Phosphorus requirements for 90% of maximum yield varied greatly between species, but were closely related to maximum yield. Thus species with low P requirements for maximum yield were not necessarily P-efficient species. In the third and subsequent years of the trial Lotus corniculatus performed better than the other pasture legumes at the lower rates of added P. In contrast to other studies Lotus pedunculatus showed no ability to outyield Trifolium repens at low rates of P. Critical P concentrations of the pasture species for the late spring-early summer period declined in the order Trifolium repens (0.34%) > Lotus pedunculatus (0.30%) > Triofolium pratense (0.28%) > Trifolium hybridum (0.27%) > Trifolium ambiguum (0.26%) > Lotus corniculatus (0.23%).Mineralisable nitrogen (N) levels were determined in soils under three species in the 7th year of the trial. At the lowest rates of added P, mineralisable N levels were much higher under Lupinus polyphyllus than under Trifolium repens or Lotus corniculatus. With increasing P rate, levels under the latter species increased, and at 100 kg P ha^-1 were equivalent to those under the lupin with no added P.     

应用RAPD技术辅助蝴蝶兰辐射育种

应用RAPD技术对蝴蝶兰辐射诱变苗进行分析。结果表明,对蝴蝶兰5种不同形态的诱变苗和对照苗进行PCR扩增,13个引物所产生的RAPD谱带大小为200~3 000 bp,共扩增77条带,多态性带61条,多态率79.22%。13个引物平均扩增的带数为5.92,引物S0036最多,为9条带。比较诱变苗与对照苗谱带,两者有差异,表明诱变苗是由基因突变引起。     

弯孢类炭疽菌菌株的RAPD分析与分类研究

通过RAPD分析对38个不同寄主来源的弯孢类炭疽菌菌株的系统发育及分类进行研究。结果表明:许多引物的RAPD扩增带型在种内是相似或一致的,而种间差异较大。UPGMA聚类分析的结果表明:38个弯孢类炭疽菌菌株被聚为6个类群,群内菌株之间遗传相似性较高,而群间遗传相似性较低;群与群之间分界明显,表明种的分界相当明显。因此,RAPD分析所反映的种间亲缘关系,将有助于疑难种分类地位的确定和近似种的区分。RAPD分析的结果还揭示了一些近似种的分类关系,如按传统方法分别鉴定为Colletotrichumtruncatum、C.circinans和辣椒炭疽菌C.capsici的许多菌株聚类在同一群内,有很高的遗传相似性,实验结果支持它们为同一个种。实验中还发现5条辣椒炭疽菌的特有片断,分别由引物OPE-14、OPH-15(2条)、OPM-12和OPM-20扩增产生。这些特异带的发现对该菌的快速检测和鉴定具有重要意义。     

Occurrence of Yeasts in Cloacae of Migratory Birds

Several species of yeast have been reported as pathogens in humans based on increases in immunodeficiency syndromes and as a result of immunosuppressant chemotherapy in cancer treatment. Domestic and wild birds are known to act as carriers of human pathogenic fungi. To gain additional information on the yeasts present in the cloacae of some species of migratory birds, 421 wild birds (24.39% out of 1726 birds caught in Romania, Hungary and Bulgaria) were sampled with the permission of the local judicial authority. The state of conservation of the birds (i.e. post-mortem alterations, colour of the mucosae etc.), along with their age and sex were determined. Samples were collected directly from the cloacae and cultured, and colonies were identified in each positive sample. Yeasts were isolated from 15.7% of the animals sampled, with the highest percentage found in coots (Fulica atra −58.8%) and the lowest in quails (Coturnix coturnix −1.7%). A total of 131 isolates belonging to 15 species of yeast were identified. Rhodotorula rubra was the yeast with the highest number of isolates (28.2%), followed by Cryptococcus albidus (18.4%), Candida albicans (9.2%), Trichosporon cutaneum (8.4%), Candida guilliermondii (6.1%), Candida tropicalis (6.1%) and other species. The present study represents the first survey on the occurrence of yeasts in the cloacae of migratory birds. The prevalence and species of yeasts isolated is discussed on the basis of the ecology, diet, and habitat of the birds.     

迷果芹（Sphallerocarpus gracilis）和红三叶（Trifolium pratense）的核型分析

对迷果芹（Sphallerocarpus gracilis(Bess.)K-Pol)和红三叶（Trifolium pratense L.)进行了染色体计数及核型分析。迷果芹的染色体数目为2n=20,核型公式为K（2n)＝2x=20=14m 4sm 2st(SAT);核型类型为2A,为较对称核型,该种植物的染色体数目及核型均为首次报道。红三叶的染色体数目有2n=14、16、28、32等类型,本研究首次报道了2n=14的核型公式为K（2n)=2x=14=2M 12m,核型类型为1B,为较原始的对称核型。