Rapid Propagation of <i>Rhynchostylis retusa in Vitro</i>

An efficient regeneration system of Rhynchostylis retusa was established to provide technical reference for the application of tissue culture tube seedlings in production. The mixtures of callus and protocorm from aseptic germination were used as explants. The optimal media of each stage was selected for callus proliferation, protocorm occurrence and growth, rejuvenation and rooting via a single, complete combination and orthogonal experiment. The results showed that the optimal medium for callus proliferation, protocorms occurrence and growth was 1/2 Murashige and Skoog (MS) medium adding 50 g·L⁻¹ banana puree, 0.1 mg·L⁻¹ α-naphthaleneacetic acid (NAA), 1.5 mg·L⁻¹ 6-benzylaminopurine (6-BA) and 1.0 mg·L⁻¹ kinetin (KT) with 17.33 proliferation coefficient of callus and 19.63 occurrence coefficient of buds after 90 days. Then the buds occurred from protocorm were cultured on 1/2 MS medium including 100 g·L⁻¹ banana puree, 1.0 mg·L⁻¹ NAA, 2.0 mg·L⁻¹ 6-BA and 0.05 mg·L⁻¹ KT, in which the proliferation coefficient of callus was 10.32 and occurrence coefficient of buds reached 17.87. In the further subculture, the same medium was simultaneously used for callus proliferation, protocorm occurrence and bud growth. The plantlets developed roots in 1/2 MS medium containing 70 mL·L⁻¹ coconut water and 1.5 mg·L⁻¹ NAA with 100% rooting rates after 90 days. The survival rate was more than 90% after domestication and transplantation. This regeneration protocol will provide technique foundation for protecting wild resource and developing artificial cultivation.     

松嫩平原退化草地羊草种子萌发对环境因子的响应

研究了温度(恒温和变温)、水分(含水量2.5%-40.0%)和干旱胁迫、土壤类型(盐碱土和非盐碱土)和盐碱胁迫(NaCl和Na₂CO₃)等环境因子对羊草(Leymus chinensis)种子萌发的影响。恒温下未经打破休眠处理的羊草种子发芽率不足2%, 变温下羊草种子发芽率可达85.3%, 表明温度是影响羊草种子萌发的关键因素之一。羊草种子萌发的适宜土壤含水量为2.5%-15.0%, 随着含水量继续增加, 发芽率呈下降趋势。松嫩平原盐碱化土壤对羊草种子萌发具有显著的抑制作用, 羊草种子在重度盐碱土(pH 10.24)中发芽率仅为6.0%, 而在非盐碱土中发芽率可达61.3%。羊草种子在萌发阶段的耐盐碱能力差, 随着NaCl和Na₂CO₃浓度增加, 发芽率呈显著下降趋势, 且Na₂CO₃的抑制作用更强。松嫩平原盐碱环境下羊草种子萌发受到抑制是该地区羊草草地退化的原因之一。     

龙脑樟幼茎愈伤组织的诱导

以龙脑樟Cinnamomum camphora chvar. Borneol组培苗幼茎为材料诱导优良愈伤组织,采用正交设计法,以愈伤组织的出愈时间、诱导率、生长状态、鲜重生长指数和右旋龙脑含量为指标,筛选最适培养基,尤其是培养基中最佳生长调节剂组合,为利用龙脑樟细胞悬浮培养调控右旋龙脑提供理论依据。结果表明,龙脑樟组培苗幼茎诱导愈伤组织的最适培养基为MS + 2,4-D 2 mg·L-1 + 6-BA 0.6 mg·L-1,右旋龙脑的提取产量为2.6698 μg·g -1 DW。     

渗透剂对白刺花体细胞胚成熟及萌发的影响

该研究以蔗糖、麦芽糖、山梨醇及PEG(6000)为渗透剂,探讨了不同渗透剂对白刺花体细胞胚发育、胚成熟及萌发的影响。结果表明:白刺花下胚轴形成的胚性愈伤组织接种至MS+2,4-D 0.2 mg·L~(-1)+NAA 1.0 mg·L~(-1)+6-BA 2.0 mg·L~(-1)+TDZ 1.0 mg·L~(-1)+蔗糖40 g·L~(-1)+谷氨酰胺100 mg·L~(-1)+植物凝胶3g·L~(-1)的培养基上,体细胞胚发生率高达66. 21%,总胚数为79个; 7%蔗糖可使体细胞胚成熟率高达64.36%,同时也可提高多子叶畸形胚形成; 2%麦芽糖+2%山梨醇+4%蔗糖组合使体细胞胚成熟率最高达88.89%,畸形胚比例最低; 30 g·L~(-1)PEG培养时,体细胞成熟率最高,为82.35%;鱼雷期的体细胞胚最合适转接,可使体胚萌发率达90.58%,复合糖上培养得到的成熟体细胞胚生根率最高,为87.47%。这为实现白刺花体细胞胚育苗奠定了理论基础,并提供了可行的方案。     

两种外源化学物影响PEG胁迫对水稻根系的伤害

研究过氧化氢内源消除剂和交替氧化酶专一性抑制剂影响渗透胁迫对水稻根系的伤害。结果表明:PEG 6000胁迫抑制了水稻幼根的生长,降低了相对含水量、增加了H₂O₂含量,并导致细胞死亡。用5 mmol·L^-1二甲基硫脲(过氧化氢内源消除剂,dimethylthiourea,DMTU)预处理水稻幼根能明显降低PEG胁迫下水稻幼根过氧化氢的含量,缓解细胞死亡和相对含水量的降低,但对水稻根的生长影响较小。在PEG胁迫下,用1 mmol·L^-1水杨基氧肟酸(交替氧化酶专一性抑制剂,salicylhydroxamic acid,SHAM)预处理水稻幼根能显著降低水稻幼根的生长和相对含水量,并增加水稻幼根的过氧化氢含量和细胞的死亡程度。这说明DMTU能缓解PEG胁迫对水稻根系伤害,而SHAM加剧了PEG胁迫对水稻根系伤害。     

AgNO3对橡胶树花药愈伤组织形态及体胚发生的影响

橡胶树的花药愈伤组织在长期继代过程中,胚性易下降甚至丧失;而AgNO3作为乙烯活性抑制剂,被广泛应用于植物组织培养中.该研究以继代培养4 a以上的热研7-33-97花药愈伤组织为材料,在继代培养基中添加2.5 mg·L-1 AgNO3预培养35 d后,观察预培养前后愈伤组织表形及其细胞形态的变化,并设计不同浓度AgNO3及不同处理时间对其进行体胚诱导,90 d后分别统计胚状体总数和正常胚数.结果表明:浅黄色质地柔软的愈伤组织在含AgNO3的培养基上预培养后能转变成鲜黄色易碎愈伤组织,在倒置显微镜下前者大多表现为不规则多边形,细胞内含物较稀薄;而后者则呈圆形或椭圆形,细胞内含物丰富,属于典型的胚性细胞.在体胚诱导的第1个月添加5 mg·L-1 AgNO3能显著促进体胚的发生,AgNO3浓度升至10 mg·L-1时体胚发生受到抑制,且畸形胚的形成率显著增加;在含5 mg·L-1 AgNO3的培养基中培养2个月以上,体胚发育明显受阻,大部分形成畸形胚.该研究结果在一定程度上恢复了橡胶树长期继代花药愈伤组织的胚性能力,并提高了其体胚发生频率,为橡胶树花药胚性愈伤组织长期继代培养过程中胚性的保持提供了参考.     

半夏缓慢生长法保存及体细胞变异的ISSR检测

以添加了不同浓度的甘露醇、PP333和ABA的培养基对半夏试管苗进行缓慢生长法保存,并对保存材料再生后代的体细胞变异进行检测。结果显示,甘露醇、PP333和ABA均能有效抑制试管苗生长,且存活率高;最佳浓度分别为甘露醇2%～4%,PP3332.0mg·L-1,ABA 2.0～4.0mg·L-1。保存在添加了2%～4%甘露醇或2.0mg·L-1 PP333培养基上的植株未检测到变异,而保存在添加了2.0～4.0mg·L-1 ABA培养基上的植株检测到1条新增标记和1条缺失标记,位点变异率为1.7%,个体变异率为30%。研究表明,ABA不宜用于半夏试管苗的缓慢生长法保存,但有助于新突变体的产生,在种质创新上具有特殊意义。     

芍药愈伤组织中体细胞胚发育过程的组织细胞学观察

以芍药（Paeonia lactiflora Pall.）3个芍药品种的茎段、叶片、叶柄为外植体,诱导体细胞胚发生,并采用石蜡切片法对该发育过程进行组织细胞学观察。结果表明：‘Going Bananas’的茎段愈伤诱导率达100%,增殖率在4.0以上,表现最佳;非胚性愈伤组织最佳诱导、增殖培养基为WPM+IAA 1.0mg·L^-1+6-BA 1.0mg·L^-1+NAA 0.5mg·L^-1+TDZ 0.5mg·L^-1+CH 0.625g·L^-1;愈伤组织转入到1/2 MS（Ca²⁺加倍）+2,4-D 2.0mg·L^-1+ABA 0.5mg·L^-1或ZT 1.0mg·L^-1的培养基中,连续暗培养90后得到胚性愈伤;之后转入到成熟培养基1/2MS（Ca²⁺加倍）+6-BA 1.0mg·L^-1+NAA 0.2mg·L^-1中,见光培养60d,逐渐发育至球形胚和心形胚。在石蜡切片观察中,芍药的体细胞胚起源方式包括外起源和内起源两个途径。在外起源方式中包括单个表层细胞的外起源和多个表层下细胞的共同起源。3种方式的区别主要在于起始的位置和起始细胞数量,后期均形成原胚结构。胚性细胞的分裂方式为对称分裂,未发现不对称分裂细胞的存在。     

Isolation of L8 and L8S8 forms of ribulose bisphosphate carboxylase/oxygenase from Chromatium vinosum

The enzyme ribulose bisphosphate carboxylase/oxygenase has been purified from Chromatium vinosum. When an extract is subjected to centrifugation at 35,000xg in the presence of polyethylene glycol (PEG)-6000 and the supernatant is treated with 50 mM Mg²⁺ and the precipitate is then fractionated by vertical centrifugation into a reoriented sucrose gradient followed by chromatography on diethylaminoethyl (DEAE)-Sephadex A50, the resultant enzyme contains large (L) and small (S) subunits. Alternatively, centrifugation of extracts at 175,000xg in the presence of PEG-6000 followed by fractionation with Mg²⁺, density gradient centrifugation, and chromatography on DEAE-Sephadex A50 yields an enzyme free of small subunits. The two forms have comparable carboxylase and oxygenase activities and have compositions and molecular weights corresponding to L₈ and L₈S₈ enzymes. The amino acid compositions of L and S subunits are reported. The L₈S₈ enzyme from spinach cannot be similarly dissociated by centrifugation at 175,000xg in the presence of PEG-6000.Abbreviations DEAE diethylaminoethyl - EDTA ethylenediamine-tetraacetate - MOPS 3-(N-morpholino)propanesulfonic acid - PEG polyethylene glycol - RuBisCO d-ribulose 1,5-bisphosphate caboxylase/oxygenase - RnBP d-ribulose 1,5-bisphosphate - SDS sodium dodecyl sulfate - SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis Dedicated to Professor G. Drews on occasion of his 60th birthday     

芘高效降解菌的分离鉴定及其降解特性

以芘为唯一碳源,采用富集培养方法,从沈抚灌区石油污染土壤中分离得到一株芘降解菌ZQ5.根据形态学观察、生理生化鉴定和16S rDNA序列分析结果,将菌株ZQ₅鉴定为寡养单胞菌属（Stenotrophomonas sp.）.采用摇瓶振荡培养方法研究该菌株降解芘的特性及培养条件对降解效能的影响.结果表明：菌株ZQ₅在30 ℃振荡培养10 d后,对100 mg·L^-1的芘降解率为91.2%,加入水杨酸（100 mg·L^-1）作为共代谢底物可以提高菌株ZQ₅对芘的降解率.当培养基pH为7～8、盐浓度不高于2%时,有利于菌株ZQ₅降解效能的发挥.     

Total Phenols,Flavonoids and Antioxidant Activity in <i>Annona muricata</i> and <i>Annona purpurea</i> Callus Culture

Callus cultures of Annona muricata and Annona purpurea were induced in Murashige and Skoog (MS) medium supplemented with different concentrations of 1-naphthylacetic acid (NAA), 6-benzyladenine (BA) and 2,4-dichlorophenoxyacetic acid (2,4-D) utilized hypocotyls with explant. The highest percentage of callus formation was the treatment supplemented with 3 mg L^-1 NAA for A. muricata (100%) while for A. purpurea in lower percentage (75%). BA stimulated the formation of shoots in all the evaluated concentrations, being the concentration of 2 mg L^-1 the one that induced the greater formation of shoots for A. muricata (23 shoots/explant) and A. purpurea (28 shoots/explant). The content of total phenols, flavonoids and antioxidant activity was measured in the callus obtained from both species. The results showed that a higher content of total phenols was quantified in callus of A. purpurea (27.8 mg g^-1 dw) compared to A. muricata (23.2 mg g^-1 dw). The highest content of total flavonoids was observed in the callus of A. purpurea (8.0 μg g^-1 dw). Antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydracil radical assay. The concentration required for 50% inhibition (IC50) of the 2,2-diphenyl-1-picrylhydracil radicals were 4.22 μg mL^-1 in methanolic extracts of callus of A. muricata, while in extracts of callus of A. purpurea was 2.86 μg mL^-1, in both cases was greater than that found for leaves. Callus culture of the species studied in this work represents an alternative for the production of natural antioxidants.     

Nutritional and hormonal requirements of Ginkgo biloba embryo-derived callus and suspension cell culture

Calli were obtained from Ginkgo biloba embryos grown on Murashige and Skoog (MS) medium. The G. biloba cells could grow on either MS or Gamborg B5 mineral salt medium supplemented with sucrose (3% and 2%, respectively) and naphthaleneacetic acid (NAA) and kinetin (K) in concentrations ranging from 0.1 to 2.0 mg·L^–1. Best growth and maintenance of callus cultures were achieved using MS medium supplemented with 2 mg·L^–1 NAA and 1 mg·L^–1 K (N₂K₁MS). Light was required to maintain healthy growth of the callus tissue.In both MS and B5 based media, sucrose was hydrolyzed extracellularly before being taken up by Ginkgo cell suspension cultures. Specific growth rates of 0.13 d^–1 and 0.08 d^–1 were obtained in MS medium supplemented with 1 mg·L^–1 NAA, 0.1 mg·L^–1 K and 30 g·L^–1 sucrose (N₁K_0.1MS) and B5 medium supplemented with the same growth regulator regime and 20 g·L^–1 sucrose (N₁K_0.1B5) respectively. Complete phosphate and ammonium uptake was observed in 11 days when cultured in MS medium and 10 days and 4 days respectively when cultured in B5 medium. During the culture, G. biloba cells consumed only 64% and 29% of the nitrate content of N₁K_0.1MS and N₁K_0.1B5 media respectively. Maximum dry biomass concentrations were 13.4 g·L^–1 and 7.9 g·L^–1, and yields on carbohydrate were 0.39 and 0.45 in N₁K_0.1MS and N₁K_0.1B5 media respectively. The better performance of MS cultures came from the higher sucrose and nitrogen salts concentrations of this medium.Abbreviations B5 Gamborg mineral salt medium - d.w. Dry weight - K Kinetin - MS Murashige and Skoog mineral salt medium - N or NAA Naphthaleneacetic acid - N_iK_jMS i and j are the respective concentrations (mg·L^–1) of NAA and K - n Number of experimental points - r Linear regression correlation coefficient     

Long-term cultured callus and the effect factor of high-frequency plantlet regeneration and somatic embryogenesis maintenance in <Emphasis Type="Italic">Zoysia japonica</Emphasis>

In this study, we have demonstrated that Zoysia japonica callus induced from mature seeds can produce high frequencies of plant regeneration and somatic embryogenesis, even following a prolonged period of subculturing. Initial callus cultures were induced from mature seeds of Japanese lawngrass (Z. japonica Steud.) incubated on a medium containing major N₆ medium salts, minor Murashige and Skoog (MS) medium salts, and modified MS medium organic elements supplemented with 3 mg L⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.01–0.02 mg L⁻¹ 6-benzyladenine. Compact callus were selected and subcultured monthly on a medium containing 2 mg L⁻¹ 2,4-D, 0.5 mg L⁻¹ kinetin, 500 mg L⁻¹ casein hydrolysate, 500 mg L⁻¹ proline, and 500 mg L⁻¹ myoinositol. Callus maintained in vitro for 18 mo could be induced to regenerate plantlets with a frequency of >90%. By contrast, 36-mo-old callus cultures failed to produce normal shoot regeneration. However, the addition of CuSO₄ to the subculture media maintained >90% regeneration frequencies in such long-term callus cultures. Histological observations revealed that plant regeneration occurred both through somatic embryogenesis and organogenesis pathways. The ability to sustainable regeneration in long-term callus cultures will be valuable to the program of genetic transformation and somaclonal variant selection.     

Selection and characterization of mannitol-tolerant callus lines of Vigna radiata (L.) Wilczek

An osmotically (mannitol) tolerant callus line of Vigna radiata (L.) Wilczek has been isolated from callus cultures grown on modified PC-L2 medium supplemented with increasing concentrations of mannitol. The tolerance was stable and retained after growth in the absence of mannitol selection for 2 months. The growth of the tolerant line, in the presence of mannitol (540 mol m^-3) was comparable to that of a sensitive callus line growing in the absence of mannitol. This line not only grew well on media containing up to 720 mol m^-3 mannitol, but also required 450 mol m^-3 mannitol for its optimal growth. Osmotically tolerant callus also showed increased tolerance to NaCl (0–250 mol m^-3) stress as compared to sensitive callus. Accumulation of Na⁺ was lower, and the level of K⁺ was more stable in osmotically tolerant than in sensitive calli, when both were exposed to salt. The free proline content of both tolerant and sensitive calli increased on media supplemented with mannitol or NaCl. However, the proline content of sensitive callus was higher than in tolerant callus in the presence of same concentrations of mannitol or NaCl.Abbreviations NAA -naphthaleneacetic acid - 2,4-d 2,4-dichlorophenoxyacetic acid - BAP 6-benzylaminopurine     

Optimization of Callus Induction Conditions from Immature Embryos in Maize and Plant Regeneration

This research uses the immature embryos of inbred maize lines (GSH9901, Hi01, Hi02, and Chang 7-2) as receptor materials to establish the callus induction system. These inbred lines provide the receptor materials for the genetic regeneration of maize and the verification of the genetic functions of maize. The factor experiment and orthogonal experiments were used to investigate the impacts of different genotypes, immature embryo size, shield orientation, 2, 4-D concentration, proline concentration, and folic acid concentration on the induction rate of embryogenic callus tissue. A sensitivity experiment testing glyphosate (Bar) and an antibiotic (Cefotaxime sodium) were also conducted. The results indicate that the immature embryos of inbred maize line GSH9901 were the most effective for callus tissue induction, and the immature embryos with a length of 1.6-2.0 mm produce the best result. The upward shield face is more successful for the formation of induced callus. Using orthogonal analysis, we found that the optimal combination for the induction system was A₃ (2,4-D concentration 0.25 mg mL^-1 ), B₁C₃ (proline concentration 0.8 mg mL^-1 ), and D₂ (folate Concentration 0.5 mg mL^-1) and the induction rate reached 84%. We found that cold storage at 4 °C for 1 d is more conducive for the formation of embryogenic callus than the other treatments tested. The sensitivity experiment for callus tissue screening revealed the critical concentration of glyphosate to be 10 mg ml^-1 , and the critical concentration of antibiotic is 250 mg ml^-1 . Using this combination of glyphosate and antibiotic resulted in regenerated plants. This study established the optimal conditions for immature embryo callus tissue induction in maize.     

Water status and growth of loblolly pine (Pinus taeda L.) callus

Water status of Pinus taeda L. callus supported on Murashige and Skoog (MS) liquid medium was characterized over an 8 week period using thermocouple psychrometry. Medium with 30 gl⁻¹ sucrose was used to produce a high water potential (Ψ_w) of −0.4 MPa (H), and the same medium was used to create a moderate Ψ_w of −0.7 MPa (M) by the addition of 10% polyethylene glycol (PEG, w/v, MW=8000). Calli were produced from cotyledon explants on H medium for 2 weeks and then transferred to either M or H medium. Callus absorption of PEG accounted for 40% of the callus dry weight and less than 7% of the callus fresh weight. Callus dry weight (without the PEG fraction) on M medium was 40% of that observed on H medium. Fresh weight on M medium was only 15% of that observed on H medium. The Ψ_w of both H and M media remained constant throughout the culture period. On H medium, callus Ψ_w and osmotic potential (Ψ_s) both increased 0.05 MPa/week with the callus Ψ_w approaching that of the external medium. On M medium, callus Ψ_w and Ψ_s both decreased more than 0.1 MPa/week with the callus Ψ_w decreasing greatly below that of the external medium. The latter was attributed to a rapidly produced osmotic shock induced upon callus transfer and/or PEG which caused less callus hydration and resulted in reduced growth. Callus turgor potential (Ψ_p) was estimated to be +0.02 to +0.09 MPa and turgor was maintained as callus Ψ_w increased or decreased. After 8 weeks, cell volumes from callus on M medium were 50 to 60% less than on H medium, suggesting that reduced cell volumes were related to turgor maintenance.     

In vitro screening for increased drought tolerance in rice

Summary In vitro screening at the cellular level was performed with mature seed-derived callus from five rice varieties, viz. IR 18351-229-3, IR 3185-6-3-3-2, SR 26-B, Nona Bokra, and C 14-8 of diverse geographical origin and with differential drought resistance at the in planta level. Callus was induced from mature seeds on Murashige and Skoog medium supplemented with 2.0 mgl⁻¹ (9 μM) of 2,4-dichlorophenoxyacetic acid (2,4-D) and 5.0, 10.0, and 15.0 gl⁻¹ of high molecular weight polyethylene glycol (PEG, 6000) as stressing agent to create chemical drought. Simultaneous efforts were also made to assess the effects of chemical drought in altering morphogenetic response in different varieties under in vitro culture. Seed germination was almost unaffected in SR 26-B and C 14-8, unlike in other varieties where germination was seriously affected. In general, seed germination was found to be decreased in three genotypes, viz. IR 18351-229-3, IR 3185-6-3-3-2, and Nona Bokra, with increased PEG concentrations. All genotypes displayed callus induction percentage in decreasing order with increased PEG concentrations supplemented in the callus induction medium (CIM), except SR 26-B and Nona Bokra. Callus induction was found to be more on CIM fortified with 5.0 gl⁻¹ PEG. In general, embryogenic callus induction and plantlet regeneration was found to be indirectly proportional to increased PEG concentrations used in CIM. Considering all characters, C 14-8 was found to be most appropriate in developing drought-tolerant lines under in vitro culture conditions followed by SR 26-B and Nona Bokra. A number of putative drought-tolerant plants were developed in C 14-8, SR 26-B, Nona Bokra, and IR 18351-29-3, and forwarded for field evaluation. In the majority of the progenies, a monogenic inheritance pattern for the drought tolerance character was observed.     

朱砂根愈伤组织培养及悬浮细胞系建立

以朱砂根(Ardisia crenata Sims.)无菌苗的茎段、叶片、胚轴和胚根为外植体进行愈伤组织诱导研究。结果表明:胚根在含有2,4-D的培养基中的诱导率最高,在添加5 mg L-1 AgNO3的MS+2,4-D 0.5 mg L-1+KT 0.01 mg L-1培养基中继代培养的增殖系数高达8倍以上。培养中获得了5种类型的愈伤组织(I-白色湿软状、Ⅱ-白色冰砂状、Ⅲ-淡黄色颗粒状、Ⅳ-黄绿色块状和V-绿色块状),其中Ⅱ和Ⅲ型愈伤组织可以成功建立悬浮细胞系,用M S+2,4-D 0.5 mg L-1+KT 0.01 mg L-1培养基进行固-液轮回培养,可以较好地保持悬浮细胞系。     

Application of Plackett–Burman experimental design and Doehlert design to evaluate nutritional requirements for xylanase production by <Emphasis Type="Italic">Alternaria mali</Emphasis> ND-16

The objective of this study was to use statistically based experimental designs for the optimization of xylanase production from Alternaria mali ND-16. Ten components in the medium were screened for nutritional requirements. Three nutritional components, including NH₄Cl, urea, and MgSO₄, were identified to significantly affect the xylanase production by using the Plackett–Burman experimental design. These three major components were subsequently optimized using the Doehlert experimental design. By using response surface methodology and canonical analysis, the optimal concentrations for xylanase production were: NH₄Cl 11.34 g L⁻¹, urea 1.26 g L⁻¹, and MgSO₄ 0.98 g L⁻¹. Under these optimal conditions, the xylanase activity from A. mali ND-16 reached 30.35 U mL⁻¹. Verification of the optimization showed that xylanase production of 31.26 U mL⁻¹ was achieved.     

催吐萝芙木离体培养和植株再生体系的建立

为建立催吐萝芙木(Rauvolfia vomitoria Afzel.)的快繁再生体系,以茎段为外植体,比较了植物生长调节剂对其愈伤组织诱导、分化及生根的影响。结果表明,诱导愈伤组织的适宜培养基为MS+2,4-D 1.0 mg L~(–1)+TDZ 0.5 mg L~(–1)或MS+2,4-D2.0 mg L~(–1)+TDZ 0.5 mg L~(–1),出愈率达100%且生长状况良好;诱导丛生芽的最佳培养基为MS+6-BA 3.0 mg L~(–1)+NAA 0.1 mg L~(–1),出芽率为46.6%,平均出芽数为3.04。这为催吐萝芙木的快速繁殖和遗传转化研究奠定了基础。