Plant regeneration via organogenesis from adventitious bud explants of a medicinal herb species, <Emphasis Type="Italic">Polygonatum cyrtonema</Emphasis>

Summary Explants derived from adventitious buds, rhizomes, stems, and leaves of a medicinal plant, Polygonatum cyrtonema, were studied for plantlet regeneration, and only adventitious bud explants were able to be regenerated into plantlets. Regeneration was also accompanied by the formation of rhizome-like tissue, the medicinal portion of the plant. The optimum hormone combination for plantlet regenertion was 4.44 μM benzyladenine plus 2.26 μM 2,4-dichlorophenoxyacetic acid, at which new adventitious buds were obtained from 96.6% of the adventitious bud explants, with an average of 5.2 buds per explant. The best medium for root induction was half-strength Murashige and Skoog medium with 4.57 μM α-naphthaleneacetic acid, as 92% of regenerated buds rooted. Regenerated plantlets were successfully transferred to a greenhouse with 86% survival. Histological observation indicated that new adventitious buds originated from the superficial meristematic cell cluster of the granular callus induced from adventitious bud explants via organogenesis.     

Regulatory‐associated protein of TOR (RAPTOR) alters the hormonal and metabolic composition of Arabidopsis seeds,controlling seed morphology,viability and germination potential

Target of Rapamycin (TOR) is a positive regulator of growth and development in all eukaryotes, which positively regulates anabolic processes like protein synthesis, while repressing catabolic processes, including autophagy. To better understand TOR function we decided to analyze its role in seed development and germination. We therefore performed a detailed phenotypic analysis using mutants of the REGULATORY‐ASSOCIATED PROTEIN OF TOR 1B (RAPTOR1B), a conserved TOR interactor, acting as a scaffold protein, which recruits substrates for the TOR kinase. Our results show that raptor1b plants produced seeds that were delayed in germination and less resistant to stresses, leading to decreased viability. These physiological phenotypes were accompanied by morphological changes including decreased seed‐coat pigmentation and reduced production of seed‐coat mucilage. A detailed molecular analysis revealed that many of these morphological changes were associated with significant changes of the metabolic content of raptor1b seeds, including elevated levels of free amino acids, as well as reduced levels of protective secondary metabolites and storage proteins. Most of these observed changes were accompanied by significantly altered phytohormone levels in the raptor1b seeds, with increases in abscisic acid, auxin and jasmonic acid, which are known to inhibit germination. Delayed germination and seedling growth, observed in the raptor1b seeds, could be partially restored by the exogenous supply of gibberellic acid, indicating that TOR is at the center of a regulatory hub controlling seed metabolism, maturation and germination.     

模拟干旱胁迫对巴东木莲种子萌发和芽苗生长的影响

巴东木莲原生种群天然更新差,林下鲜见更新幼苗或幼树.为探究其种子萌发和芽苗在生长期对干旱胁迫的耐受性,该文以巴东木莲种子为材料,采用不同质量浓度的聚乙二醇(PEG-6000)模拟干旱胁迫,分析干旱胁迫对其种子萌发、芽苗生长及其相关的生理生化指标的影响.结果表明:(1)不同质量浓度的PEG溶液对巴东木莲种子萌发和芽苗生长...     

In vitro adventitious shoot formation from embryonic and cotyledonary tissues of Pinus brutia Ten.

Adventitious buds were induced when isolated whole embryos, and excised cotyledons from treated seeds of Calabrian pine (Pinus brutia Ten.) were cultured on a cytokinin-supplemented medium. The adventitious buds formed directly from the cotyledons. The highest number of bud primordia were formed, with both embryos and excised cotyledons, after 6 weeks on a BAP — supplemented Schenk and Hildebrandt medium under a 16 h photoperiod. The buds, when separated and maintained individually on a full-strength medium without growth regulators, developed into well-formed shoots within 4 weeks. The average number of harvested shoots obtained (>1 cm in height) per seed over 24 weeks was 55; however, a maximum number of 152 shoots was obtained from one individual over the same period. The shoot forming capacity of the meristematic tissue was not lost after seven harvests.     

Sucrose effects on in vitro fruiting and seed production of Centaurium pulchellum

The effect of sucrose on fruiting, seed production, and seed germination of lesser centaury [Centaurium pulchellum (Sw.) Druce] was examined using explants of flowers and flower buds. Sucrose concentrations in the culture medium ranged from 0.003 to 0.3 M. It has been shown that the number of auxiliary buds, capsules dimension, number of viable seeds per capsule and seed dimensions increased with the increase of sucrose concentrations. The highest values were recorded at sucrose concentrations higher than 0.03 M, except for seeds size, which were larger at sucrose concentration ranging from 0.003 to 0.1 M. The germination of in vitro produced seeds was affected by previous culture history: a higher germination percentage was obtained in seeds that were raised from explants originally grown on medium with sucrose concentrations higher than 0.003 M.     

黄瓜种子及其萌发期的化感作用研究

以大白菜、萝卜、番茄和黄瓜种子为受体,采用实验室培养皿种子发芽生物测试法研究了黄瓜种子浸提液、种子萌发、胚根和芽苗分泌物、芽苗腐解物和芽苗浸提液的化感效应。结果表明:(1)黄瓜种子浸提液对大白菜、萝卜、番茄和黄瓜种子萌发均有化感抑制作用,即黄瓜种子内含有某些化感抑制物质。(2)在水浸提过的黄瓜种子萌发过程中,它不仅对其近邻套种的大白菜、萝卜和番茄种子萌发产生化感抑制作用,而且其胚根和芽苗分泌物对后茬播种的4种蔬菜种子发芽也表现出不同程度的化感抑制作用;黄瓜芽苗腐解物和芽苗水浸提液也对各受体蔬菜种子发芽与生长产生不同程度的化感抑制作用,且随着腐解芽苗量的增加或浸提液浓度的升高,各受体蔬菜种子的发芽指标值、化感效应指数值和综合效应值随之降低。(3)黄瓜种子浸提液及芽苗各器官的化感物质对黄瓜种子的萌发与生长产生了自毒作用,且黄瓜芽苗腐解物、芽苗浸提液、胚根及芽苗分泌物对受体黄瓜的自毒作用均为最大。研究发现,黄瓜种子浸提液、种子萌发时期以及芽苗各器官的化感物质主要是通过抑制受体胚根的生长而起化感抑制作用,即受体蔬菜种子胚根对化感效应最为敏感;因黄瓜种子及萌发期释放化感物质的途径有所不同,导致受体大白菜、萝卜、黄瓜和番茄的化感响应也不相同;在黄瓜种子萌发和芽苗生长的早期,化感物质即开始在芽苗体内进行合成与积累,一部分可通过胚根和芽苗分泌途径释放到环境中,另一部分可通过芽苗腐解途径释放化感物质,并对受体蔬菜种子萌发与生长表现出较强的化感抑制作用。     

The influence of cytokinin pulse treatments on adventitious bud formation on vegetative buds of Picea abies

Resting vegetative buds of Picea abies collected from phytotron-grown rooted cuttings of 24-year-old trees or a 12-year-old hedge were tested for their capacity to form adventitious buds after various cytokinin treatments. The most effective method for obtaining a high yield of adventitious buds within 8 weeks was to pulse treat the buds in 250 M BA for 3 h and then culture them on medium containing 5 M each of BA and kinetin for 1 week. The developmental pattern for adventitious bud production, with the formation of 10 to 20 adventitious buds per bud, was similar for all tested genotypes, although the number of buds giving rise to adventitious buds varied significantly. The capability of some clones to form adventitious buds was correlated to endogenous cytokinin content. The clone which contained most endogenous cytokinin in its resting bud had the highest potential for adventitious bud formation.     

红厚壳茎段丛生芽诱导与植株再生

红厚壳(Calophyllum inophyllum)为藤黄科红厚壳属多年生木本植物,有很高的药用价值。该研究以红厚壳带节茎段为外植体,探讨生长调节剂对腋芽萌发及丛生芽诱导、伸长和试管苗生根的影响。研究结果表明,外植体腋芽萌发和丛生芽诱导效果最好的培养基是MS+NAA1.0+TDZ0.5,在此条件下培养21天后,转入添加0.5 g·L–1活性炭且无生长调节剂的MS培养基,可有效促进不定芽的伸长。将带不定芽的外植体先在附加1.0 mg·L–1NAA的1/2MS培养基上进行生根诱导4周,之后转入附加1.0 g·L–1活性炭的无激素培养基进行根的伸长培养,这样的两步生根法能有效促进红厚壳生根。     

霍山石斛人工种子包埋繁殖体和萌发

以腋芽、原球茎、不定芽为繁殖体, 制作霍山石斛人工种子, 利用正交设计探讨麦芽糖、6-BA/NAA、活性炭、海藻酸钠、离子交换时间五个因素对霍山石斛人工种子萌发的影响; 并对人工种皮的糖分泄漏率以及pH的变化进行测定, 另外对霍山石斛人工种子的贮藏和防腐做了初步研究。结果表明: 麦芽糖是影响霍山石斛人工种子萌发的主要因素, 适宜的处理组合为麦芽糖含量为4%、6-BA/NAA 10:1, 活性炭浓度0.1%, 海藻酸钠浓度4.0%, 将含有繁殖体的此配方溶液滴入2% CaCl2溶液中, 进行离子交换反应, 反应时间10 min。以腋芽, 原球茎, 不定芽为繁殖体的霍山石斛人工种子萌发率分别可达到65.6%、90.1%、75.2%, 萌发后幼苗的存活率分别为16.1%、80.6%和19.1%。4°C下贮藏20 d后, 霍山石斛人工种子以腋芽, 原球茎, 不定芽为繁殖体的萌发率分别为3.3%、10.6%、5.2%。包埋剂加入多菌灵后, 自然条件下萌发率分别可以达到6.8%, 13.8%, 7.9%。     

霍山石斛人工种子包埋繁殖体和萌发

以腋芽、原球茎、不定芽为繁殖体, 制作霍山石斛人工种子, 利用正交设计探讨麦芽糖、6-BA/NAA、活性炭、海藻酸钠、离子交换时间五个因素对霍山石斛人工种子萌发的影响; 并对人工种皮的糖分泄漏率以及pH的变化进行测定, 另外对霍山石斛人工种子的贮藏和防腐做了初步研究。结果表明: 麦芽糖是影响霍山石斛人工种子萌发的主要因素, 适宜的处理组合为麦芽糖含量为4%、6-BA/NAA 10:1, 活性炭浓度0.1%, 海藻酸钠浓度4.0%, 将含有繁殖体的此配方溶液滴入2% CaCl2溶液中, 进行离子交换反应, 反应时间10 min。以腋芽, 原球茎, 不定芽为繁殖体的霍山石斛人工种子萌发率分别可达到65.6%、90.1%、75.2%, 萌发后幼苗的存活率分别为16.1%、80.6%和19.1%。4°C下贮藏20 d后, 霍山石斛人工种子以腋芽, 原球茎, 不定芽为繁殖体的萌发率分别为3.3%、10.6%、5.2%。包埋剂加入多菌灵后, 自然条件下萌发率分别可以达到6.8%, 13.8%, 7.9%。     

Induction of Adventitious Buds on Buds of Norway Spruce (Picea abies) Grown in vitro

Resting vegetative buds of Norway spruce, Picea abies (L.) Karst., were induced to form adventitious bud primordia when cultured on medium -containing cytokinin. After transfer of the induced buds to medium lacking cytokinin, adventitious buds developed. The adventitious buds arose from meristems formed de novo in the needle primordia. No differences were found in the ability to form adventitious buds among buds collected from trees ranging from 5–50 years old.     

Adventitious shoot bud formation and plant regeneration from <Emphasis Type="Italic">In vitro</Emphasis>-cultured stem segments of reed (<Emphasis Type="Italic">Phragmites communis</Emphasis> Trin.)

Summary A protocol for large-scale propagation of Phragmites communis Trin. by adventitious bud formation and plant regeneration was established. Adventitious buds were induced through either the indirect pathway or the direct pathway from stem explants of Phragmites communis. In the indirect pathway, it was essential to decrease the level of 2,4-dichlorophenoxyacetic acid from 9.1 to 0.5 μM to induce adventitious buds and achieve plant regeneration. In the direct pathway, the effects of different benzylaminopurine (BA) concentrations in the medium, and different positions of the explants, on adventitious bud formation were determined. Murashige and Skoog (MS) medium supplemented with 5.4μM α-naphthaleneacetic acid (NAA) and 53.4 μM BA, and the bottom part of stem explants were most responsive for the differentiation of adventitious shoot buds. The highest differentiation frequency was 20–30 adventitious shoot buds per stem node tissue. Elongation and proliferation of adventitious buds were achieved on MS medium supplemented with 13.3 μM BA and 5.4 μM NAA. Shoots were rooted in liquid half-strength MS medium with 5.4 μM NAA+4.9 μM indole-3-butyric acid. Rooted plants survived (87.5%) and grew well after transfer into soil for 4 wk. More than 20 000 regenerated plants of a salt-tolerant variant line of Phragmites communis have been produced. This protocol is useful for clonal micropropagation and possibly for Agrobacterium- mediated gene transfer in P. communis.     

REPRODUCTIVE ATTRITION IN THE RARE CHAPARRAL SHRUB FREMONTODENDRON DECUMBENS LLOYD (STERCULIACEAE)

We examined reproductive attrition in Fremontodendron decumbens to characterize sexual reproduction in this rare California shrub. Reproductive individuals produced an average of 2,900 flower buds in a season, with no significant difference in bud production between two seasons. Because of intense insect predation, <;2% of initiated flower buds became mature fruits. A threefold decrease in predation of flower buds between seasons resulted in an increase in seed output the second season, indicating that seed production was partially predator-limited. Most seeds (97.8%) were dormant due to an impermeable seed coat. Breaking of the coat, mechanically or by heat, allowed high levels of germination. Chamise charate and ash added to the potting medium resulted in the highest level of germination and emergence. Rodents were more important than birds as seed predators, destroying 90% of seeds under parent shrub canopies within 8–10 months. Seeds already integrated into the seed bank were comparatively safe from predation, relative to newly added seeds. If predation was prevented, seeds were long-lived under field conditions (>;80% survived after 5.75 years). Most seedlings produced in unburned chaparral by planting heat-treated seeds in openings between shrubs were destroyed by predators (rodents and insects). All seedlings that escaped predation died during the summer drought. We concluded that sexual reproduction was limited by (in order of importance): 1) lack of fire, 2) predehiscence predation by insects, and 3) postdehiscence predation by rodents. Size distributions from two populations revealed that, despite the apparent absence of sexual reproduction in unbumed chaparral, two unbumed sites contained a large proportion of individuals in small size classes. Excavation of several small individuals demonstrated they were sprouts from the roots of nearby larger shrubs. Because asexual reproduction by rootsprouting circumvents the high attrition of sexual reproductive effort on unbumed sites, rootsprouting may be a significant reproductive strategy of some ‘sprouter’ species in chaparral.     

A rice lectin receptor‐like kinase that is involved in innate immune responses also contributes to seed germination

Seed germination and innate immunity both have significant effects on plant life spans because they control the plant's entry into the ecosystem and provide defenses against various external stresses, respectively. Much ecological evidence has shown that seeds with high vigor are generally more tolerant of various environmental stimuli in the field than those with low vigor. However, there is little genetic evidence linking germination and immunity in plants. Here, we show that the rice lectin receptor‐like kinase OslecRK contributes to both seed germination and plant innate immunity. We demonstrate that knocking down the OslecRK gene depresses the expression of α–amylase genes, reducing seed viability and thereby decreasing the rate of seed germination. Moreover, it also inhibits the expression of defense genes, and so reduces the resistance of rice plants to fungal and bacterial pathogens as well as herbivorous insects. Yeast two‐hybrid and co‐immunoprecipitation experiments revealed that OslecRK interacts with an actin‐depolymerizing factor (ADF) in vivo via its kinase domain. Moreover, the rice adf mutant exhibited a reduced seed germination rate due to the suppression of α–amylase gene expression. This mutant also exhibited depressed immune responses and reduced resistance to biotic stresses. Our results thus provide direct genetic evidence for a common physiological pathway connecting germination and immunity in plants. They also partially explain the common observation that high‐vigor seeds often perform well in the field. The dual effects of OslecRK may be indicative of progressive adaptive evolution in rice.     

马铃薯离体再生及人工种子研究

马铃薯３个品种虎头,克４和Ｆａｖｏｒｉｔａ的茎叶外植体在ＭＳ＋１ｍｇ／ＬＮＡＡ＋１ｍｇ／ＬＢＡ培养基上形成愈伤组织。在ＭＳ＋０２ｍｇ／ＬＮＡＡ＋１ｍｇ／ＬＢＡ培养基上,愈伤组织分化产生不定芽。在ＭＳ＋００５ｍｇ／ＬＮＡＡ培养基上,不定芽生根形成再生完整植株。０２～０３ｃｍ大小的不定芽反复继代可持续增殖。有３个以上叶片的不定芽在ＭＳ＋５ｍｇ／ＬＢＡ＋００５ｍｇ／ＬＩＢＡ培养基上和黑暗条件下,在侧芽或顶芽部位形成微型薯。用４％海藻酸钠和２％氯化钙溶液包裹０２～０３ｃｍ大小的不定芽或直径为０２～０３ｃｍ的微型薯制成微芽人工种子和微薯人工种子。在４℃下贮存２个月后,微芽人工种子和微薯人工种子在有菌腐殖土壤中播种２１ｄ的萌发率分别是１５７％和９６２％。     

Adventitious shoot formation in cultures of 30-year-old Larix decidua,L. leptolepis,L. eurolepis,and L. laricina trees

Primordial shoot explants excised from buds of one Larix decidua tree, about 30 years old, produced more adventitious buds, elongating into shoots, when grown on half strength Litvay medium than when grown on other basal media. Thidiazuron and N₆-benzyladenine (BA) were equally effective in adventitious bud induction. In a comparative study of 30-year-old L. decidua, L. leptolepis, L. eurolepis, and L. laricina trees, explants from L. eurolepis and L. decidua produced a high number of cultures with adventitious buds that elongated into shoots; those from L. leptolepis were less productive, and those from L. laricina failed to form adventitious buds. The highest response was obtained with material collected in August and September, and in March and April; the lowest response occurred in explants from the October collection.