大蕉幼雄花易碎胚性愈伤组织长期继代培养及其植株再生

大蕉未成熟雄花接种到胚性愈伤组织诱导培养基中,4～5个月后可诱导出胚性愈伤组织,并可在继代培养基上长期增殖。这些继代培养了6年多的松软易碎的胚性愈伤组织转移到含有0.2 mg/L 6-BA的分化培养基中,可诱导出芽,得到了53株再生植株,这些再生植株可进一步扩大繁殖。组织学切片证明长期继代培养的愈伤组织维持了胚性的状态。     

电液负载敏感负载口独立多模式切换控制能效研究

针对传统电液控制系统单一工作模式能耗高、效率低等问题,提出了一种负载口独立多模式切换控制系统。该系统基于负载口独立控制,通过改变传统液压回路连接方式,为系统拓展多种节能工作模式并设计了多模式切换控制器。该控制器首先根据负载方向和速度方向,将系统切换至能量最优的工作模式;然后再根据工作模式为执行器进、出口配置最佳阀控策略,而泵控方式采用电液负载敏感方法使系统压力适应负载压力。为验证该系统在出口压力损失和能量再生两方面的节能效果,以传统电液负载敏感系统为对比对象,在小型挖掘机上进行了实验验证,并评估能效。实验结果证明,与传统电液负载敏感系统相比,采用负载口独立多模式切换控制方法在不降低运动跟踪性能的同时,能有效提高系统的能量效率,节能率达21.95%。     

Improved micropropagation protocol and enhancement in biomass and chlorophyll content in Stevia rebaudiana (Bert.) Bertoni by using high copper levels in the culture medium

Incorporation of a range of higher concentrations of CuSO₄·5H₂O in MS medium [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassay with 240 tobacco tissue cultures. Physiol. Plant 15, 473–497] significantly enhanced direct shoot bud induction and proliferation from cultured leaf and nodal explants taken from mature plants of Stevia rebaudiana. Shoot bud induction medium was supplemented with BAP (2.2 μM) and IAA (2.8 μM). When the concentration of CuSO₄·5H₂O in the induction medium was raised to 0.5 μM (five times the MS level, i.e. 0.1 μM) there was significant increase in percentage response along with increase in shoot bud number per explant. The shoots were healthy, well developed with dark green broader leaves. There was remarkable increase in total biomass and chlorophyll content at increased (0.5 μM) copper level in the medium. During proliferation stage also presence of high copper levels in the medium favoured increase in shoot bud number per explant.     

Rapid seedlings regeneration from seeds and vegetative propagation with sucker and rhizome of Eremospatha macrocarpa (Mann & Wendl.) Wendl and Laccosperma secundiflorum (P. Beauv.) Kuntze

To develop efficient seedling production methods for Laccosperma secundiflorum and Eremospatha macrocarpa, a study was conducted to examine regeneration using offsets combined with several physical and chemical treatments of seeds. Offsets categorized into small, medium and large diameters, were planted in three conditions: shaded and open nursery, and greenhouse. We tested sucker from E. macrocarpa, and sucker and rhizome from L. secundiflorum. For both species, high viability percentage (ranging from 55% to 100%) were observed for small and medium suckers planted in shaded nursery and greenhouse, against less than 49% for sucker planted in open nursery. The mean seedling emergence times were estimated to 84, 77 and 75 days after planting (DAP) for small, medium and large sucker of L. secundiflorum, respectively under open nursery condition, and 76, 75, 95 DAP for small, medium and large suckers of the same species, respectively in shaded condition. Greenhouse has a significant positive effect on E. macrocarpa seedlings emergence time. For this species, the mean seedling emergence times were estimated to 43 DAP for small sucker and 76, 93 DAP for medium and large suckers. No seedling was obtained from rhizome planted in all the growing conditions tested. Concerning seed dormancy breaking, germination percentages and rates were determined for 13 treatments. The best treatments were pre-soaking unscarified seeds for 4 days in 1.01 g l⁻¹ and 0.10 g l⁻¹ KNO₃, with 79% and 68% of germination, respectively and in 3.46 × 10⁻³ g l⁻¹ GA₃ for 68% of germination. These methods are suggested to improve germination of L. secundiflorum seeds. Successful and recommended methods for E. macrocarpa are pre-soaking scarified seeds in 3.46 × 10⁻³ g l⁻¹ and 3.46 × 10⁻⁴ g l⁻¹ GA₃, 96% and 94% of germination, respectively. Dormancy, probably a combination of mechanical and chemical dormancy, is present in the two species.     

银条茎尖玻璃化法超低温保存及其植株再生

 为长期稳定保存银条种质, 建立了玻璃化法超低温保存其茎尖的技术体系。选择继代4次的 银条无菌壮苗, 5 ℃低温驯化14 d; 剥取5 mm的茎尖, 在含有0.5 mol·L ^{- 1}蔗糖的MS (无Ca^{2 +} ) 液体培养基预培养1 d; 25 ℃条件下经改良MS + 2PVS₂装载20 min; 在- 20 ℃, 95%乙醇浴中以PVS₂脱水处理4h; 更换新鲜的PVS₃后投入液氮, 保存24 h后取出冷冻管在40 ℃水浴中化冻1 min; 以含有1.2 mol·L ^{- 1}蔗糖的改良MS (无Ca^{2 +} ) 溶液洗涤2 次, 每次10 min; 冻存后的茎尖相对存活率超过70%。将冻存后的茎尖转接到再生培养基上, 暗培养20 d后转入正常光照条件下培养, 存活率达63.7%; 继续培养得到正常分化和生长的再生植株, 生根后可移栽成活。     

黄瓜游离小孢子培养诱导成胚和植株再生

 以10个不同基因型黄瓜为试材进行游离小孢子培养,通过对成胚条件的系统研究,从‘7447’和‘Poinsett97’中获得了子叶形胚和再生植株。研究结果表明：基因型和小孢子发育时期是限制黄瓜游离小孢子成胚的关键因子。不同品种间胚状体产量差异显著,每皿产胚1.5～33.4个。单核靠边期是进行黄瓜游离小孢子培养的最佳时期。低温预处理有利于胚状体的诱导,4 ℃预处理2～4 d为宜,以处理2 d时胚状体产量最高。外源激素在诱导胚状体时并非必需,但低浓度的外源激素（0.5 mg·L^-1 2,4－D、0.2 mg·L^-1 6－BA）更能促进小孢子成胚。NLN和B5两种基础培养基在诱导胚状体上无显著差异。子叶形胚易分化成苗,而其它类型的胚状体不能获得再生植株。     

茄子的组织培养和植株再生体系研究

以2个茄子品种：红茄和紫长茄的子叶和下胚轴为外植体,探讨了不同生长调节物质对外植体分化的影响和不同品种、不同外植体的分化能力差异,并建立了茄子的高频率离体再生体系。结果表明：培养基MS＋2,4-D 1.0 mg/L＋6-BA 0.5 mg/L诱导愈伤组织效果最好;诱导不定芽方面,培养基MS＋4-PU 0.1 mg/L诱导效果最好;1/2MS培养基较MS培养基更适合植株生根。     

菊苣子叶离体培养与植株再生的研究

以菊苣无菌苗的子叶为外植体,研究其在附加不同浓度NAA和6-BA的培养基上的分化情况.结果表明:在不同培养基上,菊苣子叶均能诱导出淡黄色的愈伤组织和分化形成不定芽,但不同基因型菊苣的出愈率和不定芽诱导存在明显差别.诱导Rossa di Verona tardiva selez prelude和Rossa di treviso菊苣愈伤组织形成和芽分化的最佳培养基为MS+NAA 0.5 mg/L+6-BA 2 mg/L;而诱导In miscuglio菊苣愈伤组织和芽分化的最佳培养基为MS+NAA 0.5 mg/L+6-BA 3 mg/L.     

Callus induction and plant regeneration from lateral shoots of herbaceous bamboo Mniochloa abersend

Callus induction and plant regeneration of Mniochloa abersend via lateral shoots were conducted in this study. Murashige and Skoog (MS) medium supplemented with 1.0 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.0 mg/L naphthaleneacetic acid (NAA) was effective for compact callus induction. Remarkably, calli on the MS medium with 0.1 mg/L 2,4-D yielded the highest folds of proliferation (8.01), and showed a high potential capacity to differentiate 1 year after subculture. In addition, the compact calli possessed 100% differentiation rate and generated more shoots that were green and strong in 1.0 mg/L kinetin and 1.0 mg/L NAA. Vigorous roots were generated in the 1/2MS supplemented with 0.5 mg/L indole-3-butyric acid, and the resultant plantlets exhibited 90% survival rate after they were hardened and transplanted. The established regeneration system of M. abersend provides a promising platform for bamboo gene function study.     

Sorghum extrusion process combined with biofortified sweet potato contributed for high iron bioavailability in Wistar rats

This study aimed to evaluate the effect of sorghum and sweet potato on the bioavailability of iron, gene expression of proteins involved in iron metabolism and the plasma antioxidant capacity in animals fed with whole sorghum grains processed by dry heat or extrusion, combined or not with sweet potato flour with high content of carotenoids. Five experimental groups were tested (n = 7): dry heat sorghum flour (DS); extruded sorghum flour (ES); whole sorghum flour + sweet potato flour (DS + SP); extruded sorghum flour + sweet potato flour (ES + SP) and positive control (FS). The evaluations included: hemoglobin gain, hemoglobin regeneration efficiency, gene expression of divalente metal transporter 1 (DMT-1), duodenal citochroma B (DcytB), ferroportin, hephaestin, transferrin and ferritin and total plasma antioxidant capacity (TAC). The ES + SP group showed higher (p < 0.05) expression of DcytB, ferroportin and hephaestin when compared to the control group. The DS group showed high (p < 0.05) expression of DMT-1 and the ES showed high mRNA expression of transferrin and ferritin. The changes in the sorghum physicochemical properties from extrusion process reduced the iron and phytate content, and increased the gene expression of proteins involved in iron metabolism, improving iron bioavailability. The combination of sweet potato and sorghum flour (dry or extruded) improved the iron capture and total antioxidant capacity, probably due to the presence of β-carotene and antioxidant compounds.