‘黑珍珠’番茄植株再生体系的研究

为了研究‘黑珍珠’番茄植株再生,以‘黑珍珠’番茄幼嫩叶片为外植体诱导愈伤组织,通过愈伤组织诱导培养、愈伤组织分化培养、不定芽增殖培养、生根培养和试管苗移栽,建立高效快速的‘黑珍珠’番茄再生体系。结果表明：最适宜的诱导叶片愈伤组织的培养基为MS+ 1.0 mg/L 6-BA+ 0.1 mg/L NAA,叶片外植体愈伤组织诱导率最高可达98.2%;诱导出的愈伤组织在MS+ 1.5 mg/L 6-BA+ 0.2 mg/L IBA培养基上能很好的分化出不定芽;MS+4.0 mg/L KT+ 0.01 mg/L IBA 培养基可实现不定芽芽增殖;最适宜的生根培养基为1/2MS+ (0.05~0.08) mg/L NAA,试管苗移栽成活率达92%。     

野生软枣猕猴桃组织培养及褐变处理

以野生软枣猕猴桃嫩芽、幼嫩叶片以及茎段作为外植体,研究野生软枣猕猴桃组织培养整个过程,以建立快速高效的野生软枣猕猴桃再生体系。结果表明：最适宜的诱导叶片、茎段愈伤组织的培养基分别为MS+0.5 mg/L 6-BA+1.0 mg/L NAA和MS+0.5 mg/L 6-BA+0.1 mg/L NAA;诱导出愈伤组织在MS+0.6 mg/L 6-BA+0.05 mg/L NAA培养基上能很好地分化不定芽苗;诱导幼芽产生丛生芽的培养基为MS+1.0 mg/L 6-BA+0.1 mg/L NAA;较适宜的生根培养基为1/2MS。愈伤组织继代中发现细胞生长素NAA可以防止愈伤褐化。在愈伤组织分化中,发现将分化出的芽苗再次愈伤化,可以提高分化率。     

新疆杨组培再生体系建立

以新疆杨叶片为外植体,研究新疆杨组织培养再生体系建立的主要影响因素。结果表明:诱导愈伤组织的最佳培养基组合为MS+0.5 mg/L 6-BA+0.5 mg/L 2,4-D;愈伤组织分化的最佳培养基组合为MS+0.1 mg/L TDZ+0.3 mg/L IBA,不定芽增殖的最佳培养基组合为MS+1.0 mg/L 6-BA+0.3 mg/L IBA,诱导生根的最佳培养基组合为1/2MS+0.5 mg/L IBA,新疆杨组培苗在生根培养基上形成的根条数多,苗体健壮,生根率达到100%。本研究成功建立了新疆杨组织培养再生体系,为其转基因研究工作奠定了基础。     

胡麻品种内亚7号下胚轴组织培养再生体系的建立

以胡麻品种内亚7号下胚轴为外植体,探索其下胚轴进行组织培养的培养基条件。结果表明,用75%的乙醇和1g/L的HgCl2溶液各处理种子3min是最佳的消毒方法。用MS+3.0mg/L 6-BA+0.25mg/L IAA培养基诱导外植体的出愈率最高,为98.48%,生长速率最大,是愈伤组织生长的最佳培养基。用MS+2.0mg/L 6-BA+0.5mg/L IAA培养基诱导不定芽的分化率最高,为95%,不定芽增殖系数最大,为7.67,是不定芽分化及增殖的最佳培养基;用MS+0.01 mg/L6-BA+0.75mg/L IAA培养基诱导不定芽的生根率最高,为52.26%,是不定芽生根的最佳培养基。由此建立的组织培养再生体系,其出愈率、愈伤组织的生长速率及不定芽的诱导率、增殖率高,生根情况良好,可作为胡麻品种内亚7号的适宜组织培养再生体系。     

大花绣球‘无尽夏’组培苗叶片再生植株的研究

为建立大花绣球‘无尽夏’规模化无性繁殖和高效遗传转化体系,以‘无尽夏’组培苗叶片为外植体,研究叶位、暗培养时间及不同激素组合等因素对叶片诱导形成愈伤及分化不定芽的影响。结果表明,‘无尽夏’组培苗植株中上部叶片的愈伤诱导效果好,适宜的外植体取样叶位为第3~6位叶片。初始暗培养有利于叶片形成愈伤,暗培养15~25天的效果最佳。诱导‘无尽夏’组培苗叶片形成愈伤的适宜培养基为MS+CPPU 3.0 mg/L+IBA 0.1 mg/L,其愈伤诱导率达到98%以上;愈伤增殖与不定芽分化培养基为MS+6-BA 1.0~2.25 mg/L+IBA 0.1 mg/L。     

蜈蚣珊瑚愈伤诱导及其分化正交试验设计

本研究以蜈蚣珊瑚茎段为外植体,采用正交试验设计,进行愈伤组织诱导及分化研究,并建立植株再生体系。研究表明:愈伤组织诱导的最佳外植体为带叶茎段,最佳灭菌时间为0.1%的升汞6 min;愈伤组织诱导的最佳培养基为MS+4.0 mg/L 6-BA+0.2 mg/L IBA+0.1 mg/L NAA;不定芽增殖最佳培养基为MS+3.0 mg/L 6-BA+0.3 mg/LNAA,最佳继代次数为4次;愈伤组织不定芽诱导最佳碳源为蔗糖;生根培养最佳培养基为1/2 MS+0.4 mg/L IBA。本研究通过对蜈蚣珊瑚进行离体培养,初步获得组织培养各阶段最佳培养基配方,从而实现蜈蚣珊瑚离体快繁的目的,为蜈蚣珊瑚工厂化育苗提供理论基础及技术指导。     

玉蝉花愈伤组织的诱导及植株再生研究

以玉蝉花的茎尖和嫩叶为外植体进行愈伤组织诱导和再分化研究,成功建立了通过茎尖愈伤诱导途径的植株再生体系。研究得出:玉蝉花茎尖诱导愈伤的最佳培养基为MS+6-BA 1.0mg/L+NAA 0.5mg/L+2,4-D 1.0mg/L,最高诱导率为51.51%;不定芽诱导的培养基为MS+6-BA 1.0mg/L+NAA 0.5mg/L+KT 1.0mg/L,分化率达到72.31%,平均分化不定芽数为5.81;不定芽生根最佳培养基为MS+NAA 1.5mg/L,生根率为100%。     

苎麻叶片组织培养再生植株的研究

摘要：以中苎一号叶片为外植体,研究了外植体消毒时间、培养基、生长调节物质对苎麻品种中苎一号叶片愈伤诱导、分化不定芽和生根的影响。其结果表明：先用75%酒精消毒10秒,再用0.1%升汞灭菌8分钟,同时滴入1-2滴1% HCL效果最好。中苎一号最佳叶片愈伤组织诱导基本培养基为1/2MS;最佳叶片愈伤组织诱导培养基组合为:1/2MS+0.05mg/L TDZ+0.01mg/L IAA+0.03mg/L 2,4-D;最佳愈伤分化培养基为: 1/2MS+0.5mg/L TDZ+0.02mg/L 2,4-D+0.03mg/L IAA;最佳生根培养基为:1/2MS+0.02mg/L TDZ+O.O5mg/L NAA+0.02mg/L IAA, 形成了较为完善的组织培养再生体系,再生率达到了26%以上     

降香黄檀愈伤组织培养与植株再生研究

为了实现降香黄檀工厂化快速繁殖和扩大栽培,并为降香黄檀抗寒基因导入打下一定的基础,以降香黄檀无菌实生苗茎段、叶片、根尖为外植体,MS为基本培养基,对各器官愈伤组织诱导与分化的最适培养基成分进行了研究。结果表明,可从降香黄檀无菌实生苗茎段、叶片、根尖成功地进行愈伤组织培养和植株再生。茎段、叶片、根尖诱导愈伤组织的最适培养基分别为1/2MS+6-BA 1.5 mg/L+NAA 0.10 mg/L、1/2MS+6-BA 0.5 mg/L+NAA 0.10 mg/L和1/4MS+6-BA 1.5 mg/L+NAA 0.05 mg/L;茎段、叶片、根尖的愈伤组织诱导丛生芽最适培养基分别为1/2MS+6-BA 1.5 mg/L+2,4-D 4.0 mg/L、1/2MS+6-BA 1.5 mg/L+2,4-D 3.5 mg/L和1/2MS+6-BA 1.5 mg/L+2,4-D 3.5 mg/L;茎段、叶片、根尖来源的单芽,其最佳生根培养基分别为MS+NAA 1.5 mg/L、MS+NAA 1.0 mg/L和MS+NAA 2.0 mg/L。比较茎段、叶片与根尖的愈伤组织诱导率、丛生芽诱导率和单芽生根率,得出以无菌实生苗根尖作为外植体是降香黄檀愈伤组织培养和植株再生的最佳选择。     

巴戟天胚乳诱导愈伤组织及三倍体再生

目的:利用巴戟天种子内胚乳为外植体进行离体培养获得三倍体。方法:选取未成熟巴戟天种子内胚乳,置于不同培养基上诱导愈伤组织和分化再生植株,并对植株倍性进行根尖染色体鉴定。结果:在MS+2,4-D(2,4-二氯苯氧乙酸)2.0 mg/L+6-BA(6-苄基嘌呤)1.0 mg/L培养基上诱导获得愈伤组织,诱导频率达58.9%。愈伤组织在MS+6-BA1.0~2.0 mg/L+IBA 0.1~0.5 mg/L分化培养基上分化出不定芽。不定芽在1/2 MS+IBA 0.5 mg/L上诱导生根,生根率100%。再生植株根尖细胞染色体数目为2 n=3 x=33。结论:利用巴戟天胚乳培养获得三倍体是创造多倍体新种质的有效途径。     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Mechanisms and diversity of resistance to sorghum shoot fly,Atherigona soccata

Sorghum shoot fly, Atherigona soccata, is one of the important pests of postrainy season sorghums. Of the 90 sorghum genotypes evaluated for resistance to this pest, RHRB 12, ICSV 713, 25026, 93046 and 25027, IS 33844‐5, Giddi Maldandi and RVRT 3 exhibited resistance in postrainy season, while ICSB 463, Phule Anuradha, RHRB 19, Parbhani Moti, ICSV 705, PS 35805, IS 5480, 5622, 17726, 18368 and 34722, RVRT 1, ICSR 93031 and Dagidi Solapur showed resistance in rainy season, suggesting season‐specific expression of resistance to A. soccata. ICSB 461, ICSB 463, Phule Yasodha, M 35‐1, ICSV 700, 711, 25010, 25019 and 93089, IS 18662, Phule Vasudha, IS 18551 and 33844‐5 and Barsizoot had fewer deadhearts than plants with eggs across seasons, suggesting antibiosis as one of the resistance mechanism. Five genotypes exhibited resistance with high grain yield across seasons. Correlation, path and stepwise regression analyses indicated that leaf glossiness, seedling vigour, trichome density, oviposition and leaf sheath pigmentation were associated with the expression of resistance/susceptibility to shoot fly, and these can be used as marker traits to select and develop shoot fly‐resistant sorghums.     

Reaction of tritordeum to Fusarium culmorum and Septoria nodorum

Summary Hordeum chilense is a wild barley extensively used in wide crosses in the Triticeae. It could be a valuable source of resistance to Fusarium culmorum and Septoria nodorum. Some H. chilense x Triticum spp. amphiploids, named tritordeums, were more resistant than the parental wheat line to these diseases, others were not. Average contents of ergosterol and deoxynivalenol (DON) suggested that resistance to colonization by Fusarium was the highest for Hordeum chilense, followed by tritordeum and wheat in decreasing order. In particular, the H. chilense genotypes H7 and H17 enhanced the wheat resistance to F. culmorum in its tritordeum offsprings. Resistance to S. nodorum in tritordeum was not associated with tall plant height. There is sufficient genetic variation for resistance to F. culmorum and S. nodorum among tritordeum to allow the breeding of lines combining short straw and resistance to both diseases.     

Disease resistance in protected crops and mushrooms

Summary Cultivars of tomatoes, cucumbers, lettuce and peppers have been bred for resistance to one or more pathogens. Some tomato and cucumber cultivars have resistance to a wide range of diseases. Resistance has been transient in many cases and a succession of cultivars with new genes or new combinations of resistance genes has been necessary to maintain control. There has been a number of notable exceptions and these have included durable resistance to such pathogens asFulvia fulva and tomato mosaic virus. With lettuce the resistance situation is complicated by the occurrence of fungicide resistant pathotypes. There are no strains ofAgaricus bisporus purposely bred for disease resistance.In protected flower crops only resistance to Fusarium wilt in carnations has been purposely bred but differences in disease resistance are apparent in cultivars of many ornamental crops. This is particularly so in chrysanthemums where there are cultivars with resistance to many of the major pathogens. Similar situations occur with other flower crops and pot plants. Cultivars of some species have not been systematically investigated for resistance.The need for genetic resistance will increase with the further reduction, in the limits on pesticide use and an increasing public awareness and importance of pesticide pollution.ADAS is an executive agency of the Ministry of Agiculture, Fisheries and Food and the Welsh Office.     

Genetic constitution and diversity in four narrow endemic redwoods from the family Cupressaceae

The genetic constitution and diversity of four relictual redwoods are discussed in this review. These include monotypic genera of the family Cupressaceae: coast redwood (Sequoia sempervirens), giant sequoia (Sequoiadendron giganteum), dawn redwood (Metasequoia glyptostroboides), and alerce (Fitzroya cupressoides). All four species are narrow endemics, share a number of common phenotypic traits, including red wood, and are threatened species. Fossil history suggests that the ancestors of redwoods probably originated during the Cretaceous and Tertiary periods and flourished thereafter for millions of years. Towards the end of the Tertiary period began their decline and struggle for existence that continued during the subsequent geologic upheavals and climate changes, until the survival of the present-day redwoods in the current restricted locations in the world (USA, China, and South America). Although two species, Sequoiadendron and Metasequoia, are diploids (2n = 22), and the other two are polyploids: Fitzroya a tetraploid (2n = 4x = 44), and Sequoia a hexaploid (2n = 6x = 66); they all share the same basic chromosome number x = 11. The genome size in the hexaploid Sequoia is one of the largest (31,500 MB) in the conifers, while the genome sizes of diploid Metasequoia and Sequoiadendron are about one-third (~10,000 MB) of Sequoia. Genetic diversity in the redwoods is lower than most other gymnosperms, except in Sequoia, which seems to rank near the upper quarter of the coniferous forest trees. Genomic research is sparse in the redwoods, and should be pursued for a better understanding of their genome structure, function, and adaptive genetic diversity.     

The induction in vitro of adventitious shoots in Rosa

Summary Adventitious shoots were formed on excised leaves, roots and callus of Rosa persica x xanthina and on excised leaves of R. laevigata and R. wichuraiana on culture media that included BAP and NAA as growth regulators. Shoots formed freely on freshly cultured callus of R. persica x xanthina but their production declined in successive cultures and ceased after twelve weeks. Transplantation to soil was improved by rooting plantlets in cellulose plugs in vitro and transferring plantlets to soil while still in the plugs.     

Distribution,ecology and reproductive biology of wild tomatoes and related nightshades from the Atacama Desert region of northern Chile

Over the past 20 years, several expeditions were made to northern Chile to collect populations of wild tomatoes (Solanum chilense, S. peruvianum) and allied nightshades (S. lycopersicoides, S. sitiens), and obtain information about their geographic distribution, ecology and reproductive biology. Restricted mainly to drainages of the Andean and the coastal cordillera, populations are geographically fragmented. The two nightshade species are rare and threatened by human activities. Adaptation to extreme aridity and soil salinity are evident in S. chilense and S. sitiens (the latter exhibits several xerophytic traits not seen in the tomatoes) and to low temperatures in S. lycopersicoides and S. chilense. All tested accessions are self-incompatible, with the exception of one S. peruvianum population collected at the southern limit of its distribution. Several distinguishing reproductive traits—anther color, attachment, and dehiscence, pollen size, and flower scent—suggest S. sitiens and S. lycopersicoides attract different pollinators than S. chilense and S. peruvianum. The four Solanum spp. native or endemic to Chile provide a variety of novel traits which, through hybridization and introgression with cultivated tomato, could facilitate development of improved varieties, as well as research on a variety of basic topics, including plant-pollinator interactions, abiotic stress responses, and evolution of reproductive barriers.     

The exploration of genetic resources of Portuguese cabbage and kale for resistance to several Brassica diseases

Summary Twenty three accessions of nine Portuguese cabbage and kale land races from different geographic origins were tested at the seedling stage for resistance to several important brassica diseases. Resistance to downy mildew (Peronospora parasitica), expressed as necrosis of the cotyledon mesophyll, was found in all the accessions. Type A resistance to cabbage yellows (Fusarium oxysporum f. sp. conglutinans race 1) was present in most of the landraces. Resistance to clubroot (Plasmodiophora brassicae race 6) was found in one accession of the Portuguese tree kale. High resistance to blackleg (Leptosphaeria maculans) and white rust (Albuco candida) was not detected, although several accessions showed 20 to 30% of plants with intermediate expression of resistance. All Portuguese cole accessions were susceptible to blackrot (Xanthomonas campestris pv. campestris).     

Production and characterization of intergeneric diploid cybrids derived from symmetric fusion between Microcitrus papuana Swingle and sour orange (Citrus aurantium)

Plants were regenerated from intergeneric somatic hybridization between embryogenic protoplasts of Microcitrus papuana Swingle and leaf-derived protoplasts of sour orange (Citrus aurantium L.) via electrofusion. The regenerated plants were morphologically similar to the leaf parent in growth vigor, leaf and branch structure. FCM analysis showed that they were diploids. Simple-sequence-repeat (SSR) and cleaved-amplified-polymorphic-sequence(CAPS) were employed for hybridity characterization. SSR banding patterns of the regenerated plants were identical to the leaf parent, sour orange, indicating that they possessed nuclear component derived from sour orange. DNA amplification with chloroplast and mitochondrial universal primers, followed by restriction endonuclease digestion, revealed polymorphism between the fusion parents. Therefore, this method was used to determine the cytoplasmic compositions of the regenerated plants. Banding patterns for all the polymorphic primer/enzyme combinations of the regenerated plants were similar to those of the embryogenic parent, M. papuana, suggesting that only the cytoplasmic components derived from the embryogenic parent were present in the regenerated plants. FCM, SSR and CAPS demonstrated that intergeneric diploid cybrids have been successfully obtained by symmetric fusion. Related results concerning nuclear and cytoplasmic composition of previous diploid somatic hybrids and potential mechanism for regeneration of such kind of plants are discussed herein. This revised version was published online in July 2006 with corrections to the Cover Date.     

Breeding barriers between the cultivated strawberry, Fragaria × ananassa, and related wild germplasm

Five-hundred interspecific and intergeneric crosses were performed among accessions of the wild strawberries Fragaria vesca(2x), Duchesnea indica (8x), Potentilla tucumanensis (2x) and 9 genotypes of the cultivated strawberry, Fragaria×ananassa (8x), following an incomplete diallele mating design. Crosses between D. indica and F.×ananassa produced many putative hybrids when D. indica was used as female but a few achenes and plants when used as male; therefore, pollen-pistil compatibility relations were analyzed by fluorescence microscopy in this direction of the cross. Of the genotypic combinations, 78.6% were incompatible at the stigma level and 17.2% at the first third of the style. Only 3.6% were pollen-pistil compatible and produced fruits with achenes (seven did not germinate or originated short-lived plants and nine produced normal plants). F.vesca×F.×ananassa crosses produced 35 hybrid achenes but only 14% germinated, yielding short-lived plants; histological analyses revealed that inviable seeds had less developed (or collapsed) endosperms and smaller embryos than control plump F. vesca seeds. P.tucumanensis was only used as male, with negative results. These species and genera are partially isolated by a complex system of pre- and post-zygotic barriers. Knowledge of their nature would allow the breeder to devise strategies to put the genetic variability available in the group into a useful form. This revised version was published online in July 2006 with corrections to the Cover Date.