激素和低温预处理对胡麻花药愈伤组织诱导的影响

本文以胡麻杂交组合IS×95005的F_1为材料,研究了激素和低温预处理对花药愈伤组织诱导的影 响.研究结果表明,不同培养基不仅对花药愈伤组织的诱导率有影响,而且对愈伤组织的颜色、生长速率和质地也有较大的影响.KT+2,4-D激素组合对花药愈伤组织的诱导效果优于KT+NAA.接种前花蕾4℃低温预处理能显著提高化药愈伤诱导率.在相同培养基中,低温预处理大数对愈伤诱导率起主要作用.综合考虑愈伤组织的质量和诱导率,胡麻组合1S×95005的F_1代花药愈伤诱导率存低温预处理5 d,附加KT 1.0 mg/L+2,4-D2.0 mg/L的MS固体培养基上诱导效果最好.     

宁夏主栽水稻品种高频再生体系的建立

通过对宁夏多个主栽水稻品种愈伤组织的培养,结果表明,诱导水稻愈伤组织的最适培养基是:N6+2mg/L 2,4-D+0.5/L水解酪蛋白+0.5g/L L-脯氨酸+8g/L琼脂+30g/L蔗糖;水稻愈伤组织最适分化培养基是:MS+2mg/L 6-BA+0.5mg/L NAA;水稻的最适生根培养基为:MS+0.5mg/L NAA.筛选出了诱导愈伤组织和愈伤组织分化的最适激素浓度配比和最适分化条件.     

天蓝苜蓿花药愈伤组织诱导及再生体系的建立

为获得天蓝苜蓿单倍体再生植株,本研究以野生天蓝苜蓿花药为外植体,采用正交设计L₁₆(4⁴)筛选适宜天蓝苜蓿愈伤组织诱导培养基,比较不同基本培养基及生长调节剂组合筛选适宜的分化培养基,并用1/3MS、1/2MS和MS添加不同浓度的NAA研究不定生根。结果表明:天蓝苜蓿现蕾15~25 d的花药其愈伤组织诱导效果最好,高达60.5%。4℃低温预处理2~4 d有利于愈伤组织诱导,诱导率达77.2%。适宜花药愈伤组织诱导的培养基为NB+2,4-D 1.0 mg/L+NAA 0.5 mg/L+6-BA 0.5 mg/L+TDZ 1.0 mg/L,诱导率达78.5%。比较不同基本培养及生长调节剂的不同组合发现,NB培养基愈伤组织分化效果优于B₅和MS,NB+NAA0.5 mg/L+6-BA 2.0 mg/L适宜愈伤组织的分化,分化率为66.3%。不定芽在1/3MS+NAA 0.5 mg/L中培养,生根率最高,为86.55%。本研究建立了天蓝苜蓿花药培养再生体系,获得了单倍体植株,为天蓝苜蓿的育种实践及基因组学研究提供基础材料。     

甘露醇预处理对不同基因型加工番茄花药愈伤诱导率的影响

采用6个加工番茄F_1为试验材料,研究不同浓度和不同时间甘露醇预处理对形成加工番茄花药愈伤组织的影响。结果表明:利用甘露醇预处理加工番茄花药时,有3个杂交组合在0.2 mol/L甘露醇培养基上诱导4 d时,花药愈伤组织诱导率极显著高于未进行甘露醇预处理的;有2个杂交组合在0.4 mol/L甘露醇培养基上诱导4 d时,花药愈伤组织诱导率极显著高于对照;而杂交组合20040805×P1在0.2 mol/L或0.4 mol/L甘露醇培养基上经过4 d的预处理,花药愈伤组织诱导率均极显著高于对照。说明不同基因型加工番茄花药培养利用甘露醇预处理时,需要采用不同的浓度和处理时间。     

火龙果花药培养诱导胚性愈伤组织及遗传稳定性

成年态火龙果茎段诱导的愈伤组织再分化较困难,进而影响到遗传转化效率。以红皮紫红肉的"紫红龙"火龙果花药为外植体,研究了小孢子不同发育时期、低温预处理时间、不同植物生长调节剂及浓度配比对花药诱导胚性愈伤组织的影响。结果表明,小孢子发育处于单核初期至单核靠边期的花药,其愈伤组织诱导率最高可达23.9%,但未能诱导出胚状体;而4℃低温预处理48 h,愈伤组织的诱导率可达32.8%;最适花药愈伤组织诱导的培养基为MS+2.0 mg/L 6-BA+1.0 mg/L 2,4-D+60 g/L蔗糖,诱导率为37.4%,胚性愈伤组织为黄绿色、致密状,外表有颗粒状突起。愈伤组织增殖培养基以MS+0.4 mg/L TDZ+0.8 mg/L KT效果较好,增殖系数达9.1倍以上。愈伤组织再分化培养基为MS+0.4 mg/L TDZ+0.5 mg/L 2,4-D+0.6 mg/L NAA时,愈伤组织再分化率达36.7%。通过火龙果花药诱导出愈伤组织,增殖获得大量胚性愈伤组织,再分化形成不定芽,经SRAP分子标记检测遗传性一致,能为火龙果基因工程育种和种苗快速繁育提供新的途径。     

白芦笋花药愈伤组织诱导及绿芽分化

为建立芦笋单倍体育种技术体系以解决国内芦笋新品种资源贫乏问题,笔者以白芦笋花药为外植体进行了愈伤组织的诱导及绿芽分化研究。试验结果表明,芦笋花药经过4d的冷藏(4℃)处理后,接种于含有NAA2.0 mg/L、6-BA1.0mg/L及6%蔗糖的1/2MS培养基上,可产生愈伤组织;每年的4月份接种花药的愈伤组织诱导率最高,8月份次之,11月份最低。品种间、同一品种不同单株间花药的愈伤组织诱导率不同,以‘UC155’品种(18.9%)最高,显著高于其他三个品种‘UC142’(11.6%)、‘Gijnlim’(10.3%)、‘Thielim’(5.8%),所有试验株系中以‘UC155’-8的愈伤组织诱导率最高,达83.5%;每日补充光照强度为1000 lx的光照,比全暗培养更有利于芦笋花药愈伤组织的形成;花药接种前进行离心处理(4000 r/min)30 min,不能提高愈伤组织诱导率;愈伤组织转瓶培养于NAA 0.5 mg/L、6-BA 1.0 mg/L及3%蔗糖的MS培养基上,能分化出无根绿芽;不同品种间绿芽分化率有差别,以‘Gijnlim’品种最高(67.2%),‘UC142’品种最低(14.1%);未分化绿芽的愈伤组织再转入于不含植物生长调节剂的MS培养基上培养,部分愈伤组织能分化出绿芽     

色素万寿菊杂交母本未授粉子房培养

以色素万寿菊雄性不育株未授粉子房为外植体,比较研究子房发育期、高低温处理和生长调节剂组合对愈伤组织诱导和分化的影响。结果显示:发育6~10 d,花丝刚好露出花萼,顶部呈圆柱状的花蕾愈伤组织诱导效果最好,为79.2%;低温预处理3 d,高温培养5 d有利于愈伤组织诱导;MS+2,4-D 0.5 mg/L+NAA0.5 mg/L+6-BA 0.5 mg/L+KT 0.5 mg/L为愈伤组织诱导最佳培养基,诱导率高达85.8%;NAA 1.0 mg/L+6-BA3.0 mg/L为不定芽分化适宜培养基,分化率达77.6%;1/2MS+NAA 0.2 mg/L为生根适宜培养基,生根率93.5%。本研究可为建立高效单倍体培养体系以及单倍体育种技术提供基础性资料。     

‘凤丹白’牡丹体细胞胚的诱导及萌发

以牡丹品种‘凤丹白’的胚轴为外植体,诱导体细胞胚发生,研究不同生长调节剂以及低温预处理对牡丹体细胞胚发生的影响,并对体胚发生过程进行组织细胞学观察。结果表明,体细胞胚在MS+IAA1 mg/L+TDZ 3 mg/L+KT 0.5 mg/L培养基上诱导效果最好,诱导率为40.48%,体胚在MS培养基上萌发率为39.04%,在培养基MS+6-BA 0.1 mg/L+CH (水解酪蛋白) 1.0 g/L+活性炭0.5 g/L上的进一步萌发率为35.55%,在MS+IAA 2 mg/L+GA32 mg/L上4℃低温预处理5 d,可以有效提高体胚发生,体胚诱导率提高11.42%。组织切片可以清晰观察到体胚内起源,胚性愈伤组织历经球形、心形、鱼雷形胚后发育成子叶胚。     

八仙花花药培养诱导愈伤组织

建立花药离体培养再生体系是获得单倍体的重要途径之一.先以八仙花花蕾为试材,研究花粉发育时期与花蕾和花药形态特征的相关性;然后再以3个品种八仙花花药为外植体,研究花粉发育时期、基因型、不同激素种类及浓度配比对花药诱导愈伤组织的影响.结果 表明,尚未开放的可孕花花蕾为粉紫色且有深紫色痕迹时,不孕花花萼全部着色,花粉发育处于单核靠边期,以此时期花药为外植体,其愈伤组织诱导率最高,可达36.7％;最适宜的花药愈伤组织诱导培养基为MS+6-BA 2.0 mg/L+NAA 0.1 mg/L+2,4-D 0.2 mg/L,愈伤组织为黄绿色致密结构,培养50d左右时质量最优;3个品种之间有显著的基因型差异,品种'Lanarth'在6种培养基中的花药愈伤组织诱导率均低.本研究结果为获得单倍体及八仙花的新品种培育提供一种新的途径.     

甜叶菊花药离体培养技术体系的建立

以‘皖甜1号’甜叶菊花蕾为试验材料,利用正交设计L9(34),分别以MS、B5和N6为基本培养基,研究了不同浓度的NAA、6-BA以及蔗糖和低温预处理、暗处理时间等条件,对甜叶菊花药愈伤组织诱导的影响以及不同培养基对甜叶菊花药愈伤组织分化影响。试验得出甜叶菊花药愈伤组织最佳诱导的培养基配方为MS+3 mg/L 6-BA+0.5 mg/L NAA+60 g/L蔗糖+6 g/L琼脂,低温预处理1 d、暗培养14 d有利于甜叶菊愈伤组织的诱导,甜叶菊愈伤组织分化诱导的最佳培养基配方为MS+1 mg/L 6-BA+0.2 mg/L NAA+30 g/L蔗糖+6 g/L琼脂,不定芽在不加任何植物生长调节剂的MS培养基上伸长后,接种在1/2 MS+0.1 mg/L NAA+20 g/L蔗糖+6 g/L琼脂培养基上生根效果好,生根率可达93.33%。该试验初步建立了甜叶菊花药离体培养技术体系,获得了甜叶菊花药培养再生植株,为甜叶菊新种质的创制和新品种的选育提供了帮助。     

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.