锁阳愈伤组织诱导和增殖及不定根分化

以药用寄生植物锁阳的不同部位肉质茎为外植体,研究外植体形态及植物生长调节剂配比对愈伤组织形成、增殖及不定根分化的影响,建立了高效的锁阳肉质茎愈伤组织诱导、增殖和不定根分化体系。结果表明,锁阳茎下部大小为1．5cmx1．5cmxl．5cm的外植体,维管束平行于培养基放置,有利于愈伤组织形成;外植体培养50d,愈伤组织形成。高效的愈伤组织诱导培养基为Ms＋6-BA1．0mg.L-1＋2,4-D3．0mg·L-1,愈伤组织诱导率可达67％;增殖培养基为Ms＋6．BA0．5mg·L-1。＋2,4-D1．5mg·L-1,NxsN74％;在Ms＋6．BA1．0mg·L-1＋NAA2．0mg·L-1。分化培养基中,不定根诱导率达56％。     

茉莉酸甲酯和ABA对野葛毛状根中异黄酮含量的影响

10～ 10 0 μmol·L-1茉莉酸甲酯 (MJ)可提高野葛毛状根培养液中葛根素和大豆甙元的水平 ,促进毛状根内总异黄酮含量的增加。而用 0 .5～ 2 .0mg·L-1ABA处理后 ,无论对野葛毛状根还是培养液中葛根素、大豆甙元的含量仅略有提高 ,但对总异黄酮的合成与分泌等则有显著的促进。 10 0 μmol·L-1MJ和 1mg·L-1ABA处理 2 4～ 72h ,可促进毛状根内葛根素和培养液中总异黄酮的水平 ,以处理 4 8h的增加量最大     

曼陀罗种子休眠机理与破眠方法研究

通过对曼陀罗种子生活力测定、发芽试验、吸水率测定及种子萌发抑制物研究,揭示曼陀罗种子休眠机理,并利用物理、化学法处理曼陀罗种子,以探寻打破曼陀罗种子休眠的最佳方法.结果表明:(1)新采收的曼陀罗种子为综合休眠,休眠原因包括:种皮障碍、缺少萌发所需激素以及种皮和种仁中存在萌发抑制物,其中种皮障碍是限制种子萌发的首要因素.(2)室温存储6个月可解除曼陀罗种子种仁的休眠,但种皮障碍始终是其种子萌发的限制因素.(3)机械摩擦、浓H2SO4处理和NaOH处理均可打破除曼陀罗种皮的休眠障碍,促进种子萌发,其中用10% NaOH处理90 min为破除曼陀罗种皮休眠障碍的最佳方法,且发芽率比对照提高了83%.     

若干种子处理方法对偃松种子生活力的影响

为了提高偃松种子生活力,采用水浸、NaOH溶液浸泡、PEG6000（PEG,聚乙二醇）溶液浸泡、低温冷冻、吸湿/回干5种方法对偃松种子进行处理,研究不同处理中各因素（如溶液浓度、处理时间与温度）对偃松种子生活力的影响,并采用靛蓝染色法测定偃松种子的生活力。结果表明：10%PEG6000溶液、初始温度60℃、浸泡36 h时,偃松种子生活力最强;水浸、低温处理和吸湿/回干处理方法也能提高偃松种子生活力;然而4%~12%NaOH溶液浸泡处理会导致偃松种子生活力下降。因此可将PEG6000溶液处理种子的方法应用于偃松种子萌发及人工种苗培育的实践中,使偃松资源得到更好的可持续开发与利用。     

长瓣兜兰的组织培养与快速繁殖

1植物名称长瓣兜兰（Paphiopedilum dianthum Tanget Wang）。2材料类别种子。3培养条件种子萌发培养基：（1）1／2MS＋马铃薯汁100mg·L-1（单位下同）;（2）MS＋马铃薯汁100;（3）1／2MS＋100mL·L-1椰乳;（4）MS＋100mL·L-1椰乳。原球茎继代增殖培养基：（5）1／2MS＋6-BA0．2＋NAA0．5＋100mL·L-1椰孚L;（6）1／2MS＋6-BA0．2＋NAA1．O＋100mL·L-1椰乳。壮苗及生根培养基：（7）1／2MS＋吲哚丁酸（IBA）0．2＋2g·L-1活性炭;（8）1／2MS＋IBA0．4＋2g·L-1活性炭。以上培养基均加2．0％蔗糖和0．6％琼脂,pH5．2。5．4。培养温度为（25±2）℃,光照强度为30-40μmol·m-2·S-1,光照时间为12h．d-1。     

羊草种子休眠机制及破除方法研究

羊草种子休眠程度深、发芽率低是限制栽培利用的重要因子.采用不同破除羊草种子休眠的方法,测定各处理对种子萌发的影响,以探索破除羊草种子休眠的有效途径.结果显示:(1)刺破种皮的裸种子较完整种子的萌发率、吸水速率、生活力分别由对照的6%、63%、0%显著增加到60%、86%、94%.(2)完整羊草种子分别用清水浸种1 d、30% NaOH浸种80 min、清水浸种1 d后用30% NaOH浸种60min其萌发率由6%分别显著提高到36%、60%、84%,而各浓度赤霉素处理完整种子其萌发率较对照均无显著变化. (3)采用清水浸种1 d后用30% NaOH处理60 min,再施加200 μg/g GA3综合处理,可使羊草完整种子的发芽率由6%提高到91%,接近其种子生活力94%.研究表明,羊草种子的稃与种皮不影响种子水分的吸收,但影响种子对GA3的吸收、不同程度地阻碍大分子物质的渗入、限制羊草种子内部萌发抑制物的渗出,从而引起种子休眠;分析认为稃和种皮以及种子内部萌发抑制物质是引起羊草种子休眠的主要原因.     

不同来源牛枝子种子硬实破除方法的研究

采用浓硫酸、热水和液氮3种人工破除硬实技术,在室内模拟牛枝子适生地水热条件,对2007、2008年采自内蒙古阿拉善左旗和2008年甘肃榆中栽培的牛枝子种子进行处理,以探讨同一种群不同年份和非种源地栽培一年后的牛枝子种子的硬实程度及其破除的最佳方式.结果发现:(1)采自阿拉善左旗(2007、2008年)和甘肃榆中的牛枝子初始硬实率存在显著差异,分别为98%、93%和86%.(2)阿拉善左旗和甘肃榆中的牛枝子种子对硫酸、热水和液氮处理的响应不同,浓硫酸处理的效果显著优于其它2种方法,普遍适宜于所有种批的最佳浓硫酸处理时间为25～30 min.(3)模拟温度和湿度处理表明,高温(60℃,60/20℃)和5%湿度的环境是牛枝子种子硬实破除的关键环境因素.     

精胺和亚精胺影响水稻种子萌发与温度的关系(简报)

在25℃下以0．01～1．0mmol·L-1精胺和0．01～0．1mmol·L-1亚精胺预处理水稻种子48h，可以提高16℃下萌发指数和活力指数，但对28℃下的种子萌发无影响。种子萌发时胚芽中α-淀粉酶活性和胚芽、胚根的呼吸速率的变化规律基本上与活力指数相似。     

NaCl胁迫对萝卜幼苗叶片生理特征及根尖细胞核形态的影响

对0.00(对照)～0.50 mol·L-1NaCl处理48 h后萝卜(Raphanus sativus L.)幼苗叶片的叶绿素含量、净光合速率、丙二醛(MDA)含量和相对电导率进行了测定,并观察了根尖细胞核形态变化和胁迫后幼苗生长的恢复状况.测定结果表明:经0.05 mol·L-1NaCl处理后,叶片的叶绿素含量和净光合速率均高于对照(0.00 mol·L-1 NaGl);而用0.10～0.50mol·L-1NaCl处理后,叶绿素含量和净光合速率均随NaCl浓度的提高逐渐降低且与对照差异显著,其中,经0.35 ～ 0.50 mol·L-1 NaCl胁迫处理后叶片净光合速率降至0.00μmol·m-2·s-1.随NaCl浓度的提高,MDA含量和相对电导率呈先快速上升而后逐渐下降的趋势,且均与对照差异显著;其中,经0.30 mol·L-1 NaCl处理后MDA含量最高,经0.40 mol·L-1NaCl处理后相对电导率最高.观察结果显示:经0.05～0.25 mol·L-1NaCl处理后根尖细胞核由规则的圆形向各种不规则形状转变,染色质出现不同程度的浓缩,表现出不同程度的程序性细胞死亡特征;经0.30 ～ 0.50 mol·L-1NaCl处理后则出现中空细胞与部分正常细胞并存的现象.经0.05和0.10 mol·L-1 NaCl处理后,萝卜幼苗可恢复正常生长,且株高与对照无明显差异;而经0.25 ～ 0.50 mol·L-1 NaCl处理后,幼苗均较难恢复正常生长,且随NaCl浓度的提高,幼苗出现枯萎、糜烂现象.研究结果显示:低浓度NaCl处理不仅对萝卜幼苗的生长、生理代谢及细胞核形态结构没有明显伤害反而有一定的促进作用,而高浓度NaCl胁迫可导致萝卜幼苗不可逆伤害.     

肥荚红豆种子无菌诱导植株再生及快速繁殖

以肥荚红豆种子为外植体,研究了种子预处理、诱导萌发、不定芽增殖、壮苗、生根的方法,摸索培养基中激素的最佳配比,建立了肥荚红豆组织培养快速繁殖技术。结果表明：5％～10％NaOH溶液浸泡种子1h的预处理有利于促进肥荚红豆种皮的剥离和种子萌发;适宜于种子萌发的培养基为MS（Read）＋6-BA0．5mg·L^-1＋NAA0．1mg·L^-1,萌发率可达100％;最佳增殖培养基为Read＋6．BA1．0～1．5mg·L^-1＋KT0．1mg·L^-1＋NAA0．1mg·L^-1,增殖数可达每瓶23个以上;最佳壮苗培养基为Read＋6．BA0-0．5mg·L^-1＋NAA0．1mg·L^-1：最佳生根培养基为Read＋IAA1．0mg·L^-1,其生根率可达90．54％。研究结果提高了肥荚红豆的繁殖效率,有效促进肥荚红豆组培规模化育苗技术的成熟与推广应用,对推动其产业开发应用具有重要意义。     

Dormancy Breaking and Storage Behavior of Garcinia cowa Roxb. (Guttiferae) Seeds: Implications for Ecological Function and Germplasm Conservation

The dormancy breaking and storage behavior of Garcinia cowa Roxb. seeds were investigated.The seeds of G. cowa had 8-11 months dormancy in their natural habitat. Seeds were matured and dispersed at the end of the rainy season (mid-late August to late September) and were scatter-hoarded by rodents as food for winter after the seeds had fallen to the ground. Seedlings often emerged in the forest during the rainy season (May to August) the following year. Intact seeds of G. cowa failed to germinate after being sown at 30 ℃ for 120 d and the mean germination time (MGT) of seeds cultured in a shade (50% sunlight)nursery was 252 d. The most effective method of breaking dormancy was to remove the seed coat totally,which reduced the MGT to 13 d at 30 ℃. Germination was also promoted by partial removal of the seed coat (excising the hilum and exposing the radicle) and chemical scarification (immersion in 1% H2O2 for 1 d).Unscarified seeds take up water rapidly in the first 96 h, but water was absorbed by the outside seed coat,without penetrating through it. The moisture content (MC) of G. cowa seeds was high (50% in fresh weight)at shedding. The seeds could tolerate desiccation to some extent, until the MC reached approximately 40%;below that, the viability decreases rapidly and all seeds died at approximately 17% of MC. Seed viability decreased rapidly when seeds were chilled at 4 ℃; germination was 2% after storage for 1 week. Even stored at 10 ℃, seeds began to be damaged after 4 weeks. Seed storage for 1 yr revealed that in both dry (relative humidity (35 ± 5)%) and moist (wet sand) storage conditions, seed viability declined, but germination percentages for seeds stored under moist conditions are better than for seed stored under dry conditions.Because of their low tolerance to desiccation, marked chilling sensitivity and relatively short lifespan, G.cowa seeds should be classified into the tropical recalcitrant category. The ecological implications of dormant recalcitrant seeds and cues on storing recalcitrant seeds were discussed.     

A study of the optimum drying conditions for cabbage seed following selection on the basis of a newly-emerged radicle

A series of experiments were carried out to study the effects of different drying regimes on the survival of newly-germinated (radicle emerged 0·5-1·5 mm through the seed coat) cabbage seeds and to establish a treatment for reducing the moisture content of these germinated seeds. A preliminary surface-drying step proved necessary to avoid seed agglutination during the main drying stage. Of the drying regimes compared both viability and vigour were most effectively maintained in air, conditioned to between 20 and 30°C and with 80% r.h., flowing through the seeds at 0·25 m s^-1. Under these conditions, the viability and vigour of newly-germinated seed was maintained during drying to an equilibrium moisture content of c. 14%. At this moisture content further radicle growth was prevented and seeds remained free-flowing and separate for sowing or for further treatment.     

Seed Dormancy,Seedling Establishment and Dynamics of the Soil Seed Bank of Stipa bungeana (Poaceae) on the Loess Plateau of Northwestern China

Studying seed dormancy and its consequent effect can provide important information for vegetation restoration and management. The present study investigated seed dormancy, seedling emergence and seed survival in the soil seed bank of Stipa bungeana, a grass species used in restoration of degraded land on the Loess Plateau in northwest China. Dormancy of fresh seeds was determined by incubation of seeds over a range of temperatures in both light and dark. Seed germination was evaluated after mechanical removal of palea and lemma (hulls), chemical scarification and dry storage. Fresh and one-year-stored seeds were sown in the field, and seedling emergence was monitored weekly for 8 weeks. Furthermore, seeds were buried at different soil depths, and then retrieved every 1 or 2 months to determine seed dormancy and seed viability in the laboratory. Fresh seeds (caryopses enclosed by palea and lemma) had non-deep physiological dormancy. Removal of palea and lemma, chemical scarification, dry storage (afterripening), gibberellin (GA₃) and potassium nitrate (KNO₃) significantly improved germination. Dormancy was completely released by removal of the hulls, but seeds on which hulls were put back to their original position germinated to only 46%. Pretreatment of seeds with a 30% NaOH solution for 60 min increased germination from 25% to 82%. Speed of seedling emergence from fresh seeds was significantly lower than that of seeds stored for 1 year. However, final percentage of seedling emergence did not differ significantly for seeds sown at depths of 0 and 1 cm. Most fresh seeds of S. bungeana buried in the field in early July either had germinated or lost viability by September. All seeds buried at a depth of 5 cm had lost viability after 5 months, whereas 12% and 4% seeds of those sown on the soil surface were viable after 5 and 12 months, respectively.     

不同前处理条件对薄荷种子萌发的影响

研究了不同质量浓度(10～250 mg·L~(-1))赤霉素(GA_3)以及清水浸种不同时间(6～36 h)、层积不同时间(5～20 d)和超声波处理不同时间(5～25 min)对薄荷(Mentha haplocalyx Briq. )种子萌发的影响. 结果表明, 用100～200 mg·L~(-1) GA_3处理6 h, 薄荷种子的发芽启动时间缩短且发芽率和发芽势均显著高于对照, 其中, 用150 mg·L~(-1)GA_3浸种,薄荷种子的发芽率最高(57.3%).用清水浸种6～36 h后,薄荷种子的发芽启动时间和发芽持续时间与对照无显著差异,但浸种12 h的薄荷种子发芽率极显著高于对照.于10 ℃层积5～15 d后,薄荷种子的发芽率和发芽势极显著高于对照,发芽启动时间也与对照差异显著,其中层积5～10 d的种子发芽率较高,达47.8%～52.4%.用功率50 W、频率40 kHz超声波处理5～20 min后,薄荷种子发芽率较对照有极显著提高,其中用超声波处理10 min的薄荷种子发芽率最高,达到68.3%.研究结果显示,使用功率50 W、频率40 kHz的超声波处理10 min是打破薄荷种子休眠的最佳方法,可显著提高薄荷种子的发芽率.     

Combined effects of water activity, temperature and chemical treatments on the survival of Salmonella and Escherichia coli O157:H7 on alfalfa seeds

AIMS: The objective of this study was to determine the combined effects of water activity (a(w)), chemical treatment and temperature on Salmonella and Escherichia coli O157:H7 inoculated onto alfalfa seeds. METHODS AND RESULTS: Alfalfa seeds inoculated with Salmonella or E. coli O157:H7 and adjusted to various a(w) values were subjected to simultaneous and separate treatments with chemicals and heat. The rate of death of both pathogens was correlated with increased a(w) (0.15-0.60) and temperature (5-37 degrees C) over a 52-week storage period. Higher seed a(w) enhanced the inactivation of pathogens on seeds heated at 50-70 degrees C for up to 24 h. Treatment of seeds with water, 1% Ca(OH)2, 1% Tween 80, 1% Ca(OH)2 plus 1% Tween 80 or 40 mg l(-1) Tsunami 200 at 23 or 55 degrees C for 2 min significantly (alpha=0.05) reduced populations of Salmonella and E. coli O157:H7. CONCLUSIONS: Overall, at the combinations of temperature and concentrations of chemicals tested, 1% Ca(OH)2 was most effective in killing Salmonella and E. coli O157:H7 without reducing seed viability. SIGNIFICANCE AND IMPACT OF THE STUDY: None of the treatments evaluated in this study, whether applied separately or in combination, eliminated Salmonella or E. coli O157:H7 on alfalfa seeds without sacrificing the viability of the seeds. It remains essential that practices to prevent the contamination of alfalfa seeds be strictly followed in order to minimize the risk of Salmonella and E. coli O157:H7 infections associated with sprouts produced from these seeds.     

The Light-Sensitivity of Germination of Ficus benjamina var. nuda (Moraceae) Seeds and Its Ecological Significance

In this paper , Ficus benjamina L . var . nuda seeds were used as experimental materials, effects of temperature, light , phytohormone ( gibberellin , 6-benzyladenine and ethylene ) , nitrogenous compounds ( sodium nitroprusside,nitrate , and nitrite ) on seed germination were studied , and ecological significance of light in seed germination was discussed. Under alternating photoperiod (14 h light , 10 h dark , 12μmol m- 2 s - 1 ) , final germination percentage of seeds was 87. 5% , 100% , 100% , 100% , 98% , 89% and 100% , respectively, at 15℃ , 20℃ , 25℃ , 30℃ , 35℃ , 40℃ and 30℃􊄯20℃ , mean germination time of seeds was 34 . 7 d , 16 . 3 d , 5. 6 d , 4 .8 d , 6 . 4 d , 9 d and 6 .3 d , respectively. Germination percentage of seeds which were incubated for 35 d at 15℃ , 20℃ , 25℃ , 30℃ , 35℃ , 40℃ , 30℃􊄯20℃ and dark was zero , and these seeds rapidly germinated after addition of alternating photoperiod . Light intensity of 0 . 5 - 20μmol m- 2 s - 1 markedly increased final germination percentage of seeds . However , different light intensity influencedhardly final germination percentage of seeds, but altered germination rate of seeds . Under photoperiod of 24 h , final germination percentage of seeds notably increased with increasing length of light duration . The seeds treated for 24 h ,36 h , and 48 h by continuous light could germinate at subsequent dark. Different concentrations of exogenous gibberellin, 6-benzyladenine, ethylene, sodium nitroprusside , nitrate and nitrite could not replace light and not accelerate seed germination, and these seeds rapidly gained germinablity after addition of alternating photoperiod . Germination behavior of F. enjamina L . var . nuda seeds was closely related to long-term adaptation for tropical forest .     

Asymbiotic seed germination and in vitro seedling development of the threatened orchid Hoffmannseggella cinnabarina

Hoffmannseggella cinnabarina has not been found in the wild for the last 70?yr in the State of S?o Paulo and, therefore, wild populations of this native orchid are thought to be extinct. This investigation studied seed storage at a low temperature, in vitro germination, and seedling development of H. cinnabarina in order to establish an optimized protocol for propagation, and thus assure species conservation. Seeds of different ages were incubated on Knudson C (KC), Murashige and Skoog, and Vacin and Went media with or without 1???M of N⁶-benzyladenine (BA) and exposed to either 12 or 16?h of light (30???mol?m^?2?s^?1 at 26?±?2°C). Seed surface sterilization was deleterious to 3-mo-old seeds and severely reduced the viability of the 4-mo-old seeds. More mature seeds were not affected by the sterilization procedure. In general, the germination of 4-, 5-, 6-, and 7-mo-old seeds increased when BA was added to the culture medium especially under 16?h of light. Germination rates were highest with 8- and 9-mo-old seeds, and application of BA failed to enhance germination rates further. Developmental studies revealed that this cytokinin reduced seed and protocorm mortality rates; however, protocorm development was negatively affected in its presence. Seedling development was more pronounced when KC medium with 16?h of light was used. Long-term seed storage at 4°C did not provide promising results. The protocol described in this study proved to be efficient and relevant to in vitro seed germination and initial development of H. cinnabarina, and thus will contribute to conservation of this orchid species.     

狼毒种子萌发特性与种群更新机制的研究

研究了采集于植株上的和收集于土壤种子库的狼毒(Stellera chamaejasme)种子在不同温度、光照和5种预处理(即破裂种皮、去除种皮、98％H2SO4浸种5min、0．2％KNO3浸种24h、10℃低温保存1周)条件下的萌发力。结果表明,狼毒种子萌发率较低,25℃恒温、黑暗条件下萌发率为13％,较适宜的萌发温度为30℃恒温或10～30℃变温,破裂种皮和去除种皮萌发率显著提高,25℃恒温、光暗交替条件下萌发率分别为49％和47％,浓硫酸浸种5min处理萌发率可达到32％,KON3浸种和10℃低温保存两个处理对促进狼毒种子萌发效果不明显,狼毒种子萌发对光照条件不敏感,种子硬实性是导致狼毒种子萌发率较低的主要原因,取自土壤种子库内的狼毒种子萌发率高于当年采集的种子,在自然条件下,并非每年都有狼毒种子萌发长成幼苗,种群更新时机是随机的或周期性的。