Regeneration of Shoots on Root Explants of Flax

Regeneration of shoots from adventitious root explants of flaxwas achieved for two of five cultivars tested. Root explantsof the cultivar Bombay regenerated buds on MS medium with varioussupplements, the best combination being 002 mg I^–1 NAA,1 mg I^– 6-BA, 20 mg I^– adenine and 500 mg I^–cefotaxime. Adenine, in the presence of 6-BA, and cefotaxime,in the presence of both 6-BA and adenine, were found to stimulatebud initiation, but the most important factor influencing budregeneration from flax roots was genotype     

甘蓝型油菜高效离体再生体系的建立

以甘蓝型油菜(Brassica napusL.)HC8为材料,从无菌苗苗龄、预培养基激素浓度、预培养天数、6-BA及NAA的浓度等方面对影响油菜组织培养的因素进行了分析研究,建立了甘蓝型油菜品系HC8的离体再生技术体系。结果表明,该油菜组织培养的最佳苗龄为5 d;最佳预培养时间为5 d,最佳2,4-D浓度为1.0 mg/L;子叶最佳诱导培养基为MS+2.0 mg/L 6-BA+0.05 mg/LNAA+3.5 mg/L AgNO3或MS+3.0 mg/L 6-BA+0.1 mg/L NAA+3.5 mg/L AgNO3,该条件下子叶愈伤组织诱导率最高可达100%,再生频率及分化频率分别可达88.0%和108.33%;下胚轴最佳诱导培养基为MS+4.0 mg/L 6-BA+0.05 mg/L NAA+3.5 mg/L AgNO3,子叶愈伤组织诱导率最高可达95.24%,再生频率及分化频率分别可达81.82%和104.55%;最佳生根培养基为MS+0.5 mg/L NAA,生根率最高为90.0%。     

Plant Regeneration from Petiole Protoplasts of Brassica napus

Two cultivars of Brassica napus, Altex and Canadian twins, were used as materials. Protoplasts isolated from petioles of plants grown in vitro were cultured in Nitsch medium supplemented with 0.5mg/L BA, 0.5mg/L NAA, lmg/L 2,4-D, 100mg/L serine, 800mg/L glutamine, 4% sucrose and 0.4mol/L mannitol. After 2 days of culture, the first division was observed. The division frequency estimated after 10 days of culture was 30-60%. One week after transferring onto MS medium containing 6mg/L GA3. and 3mg/L BA, protoplast-derived calli regenerated into shoots. The regeneration frequency of the two cultivars was 24% and 31% respectively. It was found that the protoplasts isolated from petioles could float on the surface of the 3% sucrose contained solution which was very favourable both to purification, and culture of the protoplasts.     

Regeneration of plants from hypocotyl protoplasts of rapessed (Brassica napus L. var. oleifera) cultivars

Protoplast cultures were prepared from hypocotyls of ten spring rapeseed cultivars. Protoplasts from all genotypes tested formed calli, and shoots were regenerated from calli of nine of the genotypes at frequencies varying from 15 to 76%. The regenerating cultivars fell into a high regenerating group (>60% and a low regenerating group <25%).     

紫苏不同外植体的培养及再生

探讨了紫苏（Perilla frutescens）不同外植体在不同激素的不同浓度及组合培养基中的培养及再生情况,建立了紫苏的高效快捷再生体系。结果表明：（1）再生率由高到低依次是茎尖、真叶、子叶和下胚轴;（2）茎尖无论有无激素处理,再生率都在85%以上,添加合适的激素可提高增殖系数。真叶在MS＋TDZ 0.05 mg/L～0.1 mg/L范围处理下再生率均达70%左右。子叶最适激素组合为MS＋KT 1.0 mg/L＋IAA 1.0 mg/L,再生率22.22%。下胚轴最适激素组合为MS＋6-BA 1.0 mg/L＋IAA 1.0 mg/L,再生率14.61%;（3）再生苗在1/2 MS中生根良好,生根率达86.67%,平均根长7.36 cm;（4）真叶外植体可形成叶簇,并可反复诱导不定芽发生,增殖能力强,培养周期短,是最理想的外植体。     

TDZ高效诱导蝴蝶兰叶片不定芽及植株再生

以蝴蝶兰（Phalaenopsis）无菌幼苗叶片为材料,研究添加TDZ（噻重氮苯基脲）条件下不同基因型、激素组合、叶片大小、暗培养时间对不定芽发生和再生植株的影响。结果表明：在相同培养条件下,不同基因型外植体芽诱导率差异显著,‘红天使’最高,达81.5%,‘汕农姑娘’等2个品种为0,‘满天红’等4个品种为9.2%～34.9%;添加TDZ芽诱导率显著高于6-BA;单独添加TDZ或6-BA芽诱导率显著高于NAA与TDZ或6-BA的组合。叶片越小不定芽诱导率越高;短时间暗处理有利于不定芽的发生。以1～2 cm长叶片为材料、15 d暗处理、在1/2 MS添加3 mg/L TDZ培养基中,‘红天使’的叶片外植体芽诱导率和平均不定芽数分别可达100.0%和18.2个。研究发现,在继代培养中TDZ对芽的伸长有抑制作用。     

Plant Regeneration from Protoplasts of Brassica Juncea L.

Protoplasts isolated enzymatically from epicotyl and growing tip of Bressica juncea divide to form callus on Kp8 medium. Plant regeneration is obtained from protoplast- derived callus of on MSD3 medium. High concentration of inositol in differentiation medium stimulates plant or shoot regeneration from the epicoty protoplast origin.     

酸枣叶片不定梢形成及玻璃化的影响因素

以酸枣无菌苗叶片为外植体,研究了培养条件对不定梢再生及不定梢玻璃化的影响.结果表明,叶片在加有细胞分裂素TDZ的诱导培养基(培养基Ⅰ)上连续培养,可诱导不定芽形成,但不能进一步发育成不定梢;而在诱导培养基Ⅰ上培养2周后转移到不加TDZ的培养基Ⅱ上,可获得不定芽伸长的不定梢.培养基Ⅱ的基本培养基组成影响不定芽(梢)的玻璃化症状:MS培养基产生玻璃化的不定芽(梢),而WPM培养基产生正常不定芽梢;光培养条件的变化对玻璃化症状的发生没有影响.不定芽(梢)玻璃化的发生可能与培养基中铵或硝酸铵的浓度有关,在不定芽伸长发育阶段,培养基中高浓度的铵导致了玻璃化苗的发生.     

In vitro Plant Formation from Stem Explants of Rape (Brassica napus cv. Zephyr)

Internodal segments from 6-weeks-old rape plants (Brassica napus L. cv. Zephyr) were induced to differentiate in vitro producing shoots or shoots and roots on synthetic nutrient medium under controlled conditions. Benzyladenine (BA) alone (5 × 10^?6 M) induced multiple shoot formation on all stem explants. Roots were induced on shoots when recultured on nutrient medium supplemented with auxins such as naphthalene-acetic acid (NAA) or indoleacetic acid (1AA) or when planted in vermiculite. Complete plant formation was obtained when NAA (2 × 1^?6, 5 × 10^?6 and 10^?5 M) was employed in conjunction with BA at 5 × 10^?6M. At higher concentrations (10^?5M) NAA retards the shoot development while 1AA suppresses it totally. Lower levels of auxins along with the cytokinin did not retard or inhibit shoot differentiation.     

In vitro Shoot Regeneration from Seedling Root Segments of Brassica oleracea and Brassica napus Cultivars

Root segments taken from aseptically-grown seedlings of Brassicaoleracea var. italica cv. Green Comet were used in an investigationof factors affecting in vitro regeneration. Shoot regenerationwas found to increase with seedling age and to be highest inroot segments adjacent to the hypocotyl and lowest in segmentsadjacent to the root tip. In a comparison of a range of mediaand agar concentrations shoot formation was favoured by complexmedia containing reduced nitrogen and was higher on gelled mediathan in liquid medium. The effects of various cytokinins andauxins were investigated; KN was the best cytokinin and IAAand Picloram the best auxins for shoot induction. Root segmentsfrom six other Brassica cultivars were grown on the medium devisedfor Green Comet; shoots were regenerated from two B. oleraceacultivars and two B. napus cultivars, but not from the B. campestriscultivars tested. Brassica oleracea var. italica, Brassica napus, Brassica campestris, seedling root culture, shoot regeneration     

Regeneration of Diploid and Polyploid Plants from the Stem Pith Explants of Diploid Marrow Stem Kale (Brassica oleracea L.)

Viable plants of kale (Brassica oleracea L.) have been regeneratedfrom stem pith explants grown on complex agar media. About 80per cent of kale plants cv. Krasa gave explants which differentiatedroots and shoots. Analysis of stomatal length, pollen grainmorphology and estimation of chromosome number in PMC and somaticcells showed that a set of 71 regenerated plants derived fromfive diploid mother plants contained 6 di-, 54 tetra-, and 11octoploid regenerates. Utilization of this method in plant breedingis discussed.     

灰绿藜幼嫩花序的组织培养及植株再生

选用盐碱地灰绿藜(Chenopodium glaucum L.)幼嫩花序为外植体,建立了快速而高效的离体组织培养体系。在附加1.0 mg/L 6-BA和0.4 mg/L IBA的MS培养基上培养35 d可诱导出不定芽,诱导频率达到66.7%;不定芽在此培养基上可快速扩增和长期继代培养。不定芽转至1/2 MS NAA 0.2 mg/L培养基中培养2~3周,生根形成完整植株。     

Gene transferability from transgenic Brassica napus L. to various subspecies and varieties of Brassica rapa

Gene transferability from transgenic rapeseed to various subspecies and varieties of Brassica rapa was assessed in this study. Artificial crossability was studied in 118 cultivars of 7 B. rapa subspecies and varieties with the transgenic rapeseed GT73 (Brassica napus) as the pollen donor. On average 5.7 seeds were obtained per pollination, with a range from 0.05 to 19.4. The heading type of B. rapa L. showed significantly higher crossability than non-heading types of B. rapa. The spontaneous outcrossing rate between B. rapa (female) and the transgenic rapeseed Ms8 × Rf3 (B. napus) (male) ranged from 0.039 to 0.406%, with an average of 0.19%. The fertilization process and the development of the hybrid seeds as shown by fluorescent staining techniques indicated that the number of adhered pollens on the stigma was reduced by 80%, the number of pollen tubes in the style was reduced by 2/3 and the fertilization time was delayed by over 20 h when pollinated with the transgenic rapeseed Ms8 × Rf3 in comparison with the bud self-pollination of B. rapa as control. About 10–70% of the interspecific hybrid embryos were aborted in the course of development. Some seeds looked cracked in mature pods, which showed germination abilities lower than 10%. The spontaneous outcrossing rates were much lower than the artificial crossability, and their survival fitness of the interspecific hybrid was very low, indicating that it should be possible to keep the adventitious presence of the off-plants under the allowed threshold, if proper measures are taken.     

Melliferous potential of Brassica napus L. subsp. napus (Cruciferae)

Morphophysiological characteristics of oilseed rape flowers, such as features of the nectaries, nectar production, and observations on honey bee visits and honey and seed yield were studied with the aim to evaluate the melliferous potential of this crop as well as its attractiveness to pollinators. Calculation of the theoretical maximal honey yield revealed that the actual amount of extracted honey was much lower than the potential yield, indicating that this bee pasture is underutilized. We found that honey bee pollination increased oilseed rape yield, i.e., seed production, by 12 % compared with the treatment in which pollinators were excluded.     

Agrobacterium-mediated transformation of thin cell layer explants from Brassica napus L.

Summary Agrobacterium-mediated transformation of thin cell layer explants (Klimaszewska and Keller 1985) yielded large numbers of transgenic plants of a major Canadian rapeseed cultivar Brassica napus ssp. oleifera cv Westar. The morphology and fertility of these plants were indistinguishable from controls. The Ti plasmid vector, pGV3850 (Zambryski et al. 1983) was used as a cis vector and as a helper plasmid for the binary vector pBin19 (Bevan 1984). Selectable marker genes that conferred resistance to high levels of kanamycin (Km) on Nicotiana tabacum were less efficient in the selection of transgenic B. napus. At low levels of Km (15 g/ml) large numbers of transgenic plants (50%) were identified among the regenerants by nopaline synthase activity and several of these were confirmed by Southern blot analyses. Only a small number were resistant to higher levels of Km (80 g/ml). Preliminary analyses indicated that resistance to Km was transmitted to the selfed progeny. Chimeric chloramphenicol acetyl transferase genes were ineffective biochemical markers in transgenic B. napus.Contribution No. 1092 Plant Research Centre, Ontario, Canada     

Metabolic Systems in the 'Root' of Brassica napus L.

This is a study of the effects of possible intermediary metaboliteson the respiration of root tissue from Brassica napus usingthe Warburg micro-manometric technique. It is concluded thatascorbic acid is oxidized by two systems, one of which appearsto be a direct oxidase and the other a dehydrogenase. No evidenceof peroxidase activity was secured. A substantial fraction ofthe total respiratory activity was insensitive to cyanide andazide. The biologically important organic acids were oxidizedwith the production of carbon dioxide. Glutamic and asparticacids were metabolized with great rapidity, glycine and alaninemuch more slowly. A scheme integrating these results is outlinedand compared with the respiratory systems existing in potato.     

The Native Structure and Composition of the Cruciferin Complex in Brassica napus

Globulins are an important group of seed storage proteins in dicotyledonous plants. They are synthesized during seed development, assembled into very compact protein complexes, and finally stored in protein storage vacuoles (PSVs). Here, we report a proteomic investigation on the native composition and structure of cruciferin, the 12 S globulin of Brassica napus. PSVs were directly purified from mature seeds by differential centrifugations. Upon analyses by blue native (BN) PAGE, two major types of cruciferin complexes of ∼ 300–390 kDa and of ∼470 kDa are resolved. Analyses by two-dimensional BN/SDS-PAGE revealed that both types of complexes are composed of several copies of the cruciferin α and β polypeptide chains, which are present in various isoforms. Protein analyses by two-dimensional isoelectric focusing (IEF)/SDS-PAGE not only revealed different α and β isoforms but also several further versions of the two polypeptide chains that most likely differ with respect to posttranslational modifications. Overall, more than 30 distinct forms of cruciferin were identified by mass spectrometry. To obtain insights into the structure of the cruciferin holocomplex, a native PSV fraction was analyzed by single particle electron microscopy. More than 20,000 images were collected, classified, and used for the calculation of detailed projection maps of the complex. In contrast to previous reports on globulin structure in other plant species, the cruciferin complex of Brassica napus has an octameric barrel-like structure, which represents a very compact building block optimized for maximal storage of amino acids within minimal space.