不同激素及其浓度配比对深山蔷薇嫩叶柄再生植株诱导的影响

以深山蔷薇新生嫩叶柄为外植体,应用均匀设计法筛选其最适合的愈伤组织诱导、愈伤组织芽苗分化和生根的培养基,结果表明,最适合的嫩叶柄愈伤组织诱导的培养基为：LS+6-BA 1.80 mg·L^-1+NAA 0.10 mg·L-1+2,4-D 0.08 mg·L^-1,诱导率为99.0%;愈伤组织再分化芽苗的培养基为：LS+6-BA 3.45 mg·L^-1+NAA 0.05 mg·L^-1,分化率为99.5%;生根培养基：1/2LS(大量元素)+IAA 0.05 mg·L^-1,生根率达98.0%以上。移栽成活率达96.0%以上。本试验成功建立了深山蔷薇嫩叶柄植株再生体系。     

Unusual metaxylem tracheids in petioles of Amorphophallus (Araceae) giant leaves

BACKGROUND AND AIMS: Petioles of huge solitary leaves of mature plants of Amorphophallus resemble tree trunks supporting an umbrella-like crown. Since they may be 4 m tall, adaptations to water transport in the petioles are as important as adaptations to mechanical support of lamina. The petiole is a cylindrical shell composed of compact unlignified tissue with a honeycomb aerenchymatous core. In both parts numerous vascular bundles occur, which are unique because of the scarcity of lignified elements. In the xylemic part of each bundle there is a characteristic canal with unlignified walls. The xylem pecularities are described and interpreted. MATERIAL: Vascular bundles in mature petioles of Amorphophallus titanum and A. gigas plants were studied using light and scanning electron microscopy. KEY RESULTS: The xylemic canal represents a file of huge metaxylem tracheids (diameter 55-200 microm, length >30 mm) with unlignified lateral walls surrounded by turgid parenchyma cells. Only their end walls, orientated steeply, have lignified secondary thickenings. The file is accompanied by a strand of narrow tracheids with lignified bar-type secondary walls, which come into direct contact with the wide tracheid in many places along its length. CONCLUSIONS: The metaxylem tracheids in A. petioles are probably the longest and widest tracheids known. Only their end walls have lignified secondary thickenings. Tracheids are long due to enormous intercalary elongation and wide due to a transverse growth mechanism similar to that underlying formation of aerenchyma cavities. The lack of lignin in lateral walls shifts the function of 'pipe walls' to the turgid parenchyma paving the tracheid. The analogy to carinal canals of Equisetum, as well as other protoxylem lacunas is discussed. The stiff partitions between the long and wide tracheids are interpreted as structures similar to the end walls in vessels.     

Impact of light quality on leaf and shoot hydraulic properties: a case study in silver birch (Betula pendula)

Responses of leaf and shoot hydraulic conductance to light quality were examined on shoots of silver birch (Betula pendula), cut from lower (‘shade position’) and upper thirds of the crowns (‘sun position’) of trees growing in a natural temperate forest stand. Hydraulic conductances of leaf blades (K_lb), petioles (K_P) and branches (i.e. leafless stem; K_B) were determined using a high pressure flow meter in steady state mode. The shoots were exposed to photosynthetic photon flux density of 200–250 µmol m^?2 s^?1 using white, blue or red light. K_lb depended significantly on both light quality and canopy position (P < 0.001), K_B on canopy position (P < 0.001) and exposure time (P = 0.014), and none of the three factors had effect on K_P. The highest values of K_lb were recorded under the blue light (3.63 and 3.13 × 10^?4 kg m^?2 MPa^?1 s^?1 for the sun and shade leaves, respectively), intermediate values under white light (3.37 and 2.46 × 10^?4 kg m^?2 MPa^?1 s^?1, respectively) and lowest values under red light (2.83 and 2.02 × 10^?4 kg m^?2 MPa^?1 s^?1, respectively). Light quality has an important impact on leaf hydraulic properties, independently of light intensity or of total light energy, and the specific light receptors involved in this response require identification. Given that natural canopy shade depletes blue and red light, K_lb may be decreased both by reduced fluence and shifts in light spectra, indicating the need for studies of the natural heterogeneity of K_lb within and under canopies, and its impacts on gas exchange.     

棉花大田植株叶柄组织培养体系的建立

以早熟棉花品种'中棉所24'为材料,通过对大田棉花植株叶柄灭菌条件、叶柄愈伤组织诱导与分化、胚状体的萌发及植株再生所需的培养基等进行研究,以建立棉花大田植株叶柄组织培养体系.结果表明:棉花植株叶柄经0.1%HgCl2灭菌4～5 min后,横切成0.8 cm左右的小段,在MSB+0.05 mg·L-1IAA+0.05 mg·L-1KT+0.05 mg·L-12,4-D+25 g·L-1葡萄糖+2 g·L-1Gel(pH 5.8)培养基上培养,易获得分化的愈伤组织;愈伤组织在添加有KT/IAA(MSB+0.08 mg·L-1IAA+0.08 mg·L-1KT+25 g·L-1葡萄糖+2 g·L-1Gel,pH6.5)或ZT/IBA(MSB+0.1 mg·L-1ZT+0.1 mg·L-1IBA+25 g·L-1葡萄糖+2 g·L-1Gel,pH 6.5)的分化培养基中,均可以获得胚性愈伤组织.胚性愈伤组织在MSB+0.05 mg·L-16-BA+0.05 mg·L-1IAA+25 g·L-1蔗糖+2 g·L-1Gel(pH 6.5)培养基上,形成胚状体、生长发育成再生植株.     

Elevated carbon dioxide plus chronic warming causes dramatic increases in leaf angle in tomato,which correlates with reduced plant growth

Limited evidence indicates that moderate leaf hyponasty can be induced by high temperatures or unnaturally high CO₂. Here, we report that the combination of warming plus elevated CO₂ (eCO₂) induces severe leaf hyponasty in tomato (Solanum lycopersicum L.). To characterize this phenomenon, tomato plants were grown at two levels of CO₂ (400 vs. 700 ppm) and two temperature regimes (30 vs. 37°C) for 16–18 days. Leaf hyponasty increased dramatically with warming plus eCO₂ but increased only slightly with either factor alone and was slowly reversible upon transfer to control treatments. Increases in leaf angle were not correlated with leaf temperature, leaf water stress, or heat‐related damage to photosynthesis. However, steeper leaf angles were correlated with decreases in leaf area and biomass, which could be explained by decreased light interception and thus in situ photosynthesis, as leaves became more vertical. Petiole hyponasty and leaf‐blade cupping were also observed with warming + eCO₂ in marigold and soybean, respectively, which are compound‐leaved species like tomato, but no such hyponasty was observed in sunflower and okra, which have simple leaves. If severe leaf hyponasty is common under eCO₂ and warming, then this may have serious consequences for food production in the future.     

Fabrication of iron oxide nanocolloids using metallosurfactant-based microemulsions: antioxidant activity,cellular, and genotoxicity toward Vitis vinifera

The present work aims at the fabrication of iron oxide nanocolloids using biocompatible microemulsion and their cytotoxic, genotoxic effect on Vitis vinifera plant has been evaluated. The three iron-based metallosurfactant complexes were synthesized. Nanosuspensions (Ns) were prepared using microemulsion technique and for the purpose, the microemulsion was prepared using oleic acid, butanol, tween 80 and as synthesized iron metallosurfactant. In this technique, no additional capping agent and/or reducing agent was added. Tween 80 which is a biocompatible surfactant acted as a reducing agent as well as stabilizing for the iron oxide Ns. Characterization of Ns’s was done using TEM, FESEM, EDX, XRD, AFM, and zeta potential. Mixed type of iron oxide nanoparticles i.e. magnetite (Fe₃O₄), and maghemite (Fe₂O₃) with a size range of 1–16 nm was found to be present in the nanosuspensions prepared from all the three precursors. The antioxidant activity of the Fe Ns was also confirmed using DPPH assay, with order of activity FeDDA > FeCTAC > FeHEXA. The cellular toxicity of Ns was evaluated by observing the morphological changes on V. vinifera plant (petiole) using a light microscope. Further, the interactions of iron oxide Ns with V. vinifera’s DNA (plant-DNA) was assessed using circular dichroism (CD) and gel electrophoresis. For the case of FeCTAC Ns, a decrease in the intensity of bands was observed indicating fragmentation or adduct formation resulting in DNA damage. In the case of FeDDA, a modest decrease in the intensity of bands was observed. However, for FeHEXA Ns, complete neutralization of bands was confirmed implying maximum damage to the plant DNA. CD, gel electrophoresis and antioxidant activity confirmed that FeHEXA Ns were most toxic and FeDDA Ns were safest among the three as-fabricated nanosuspensions.     

菜心组织培养技术初探

为建立菜心(Brassica campestris ssp.chinensis var.utilis)的快繁技术体系,以花药和子叶-子叶柄为外植体进行组织培养研究。结果表明,花药培养以选取未开放的花蕾为宜,且花柱略高于花瓣,此时小孢子多数处于单核靠边期。菜心花粉的萌发率不高,且秋冬季的花粉比夏季的萌发率高。菜心花药愈伤组织诱导培养基为:MS+1.0 mg L–1 KT+1.0 mg L–1 2,4-D+3%糖+6 g L–1琼脂+8%椰乳,不定芽诱导培养基为:MS+2.0 mg L–1 6-BA+0.5 mg L–1 NAA+1.0 g L–1活性炭+2%糖+6 g L–1琼脂或MS+2.0 mg L–1 ZT+0.5 mg L–1 IAA+0.5 g L–1 AgNO3+1.0 g L–1活性炭+2%糖+6 g L–1琼脂。花药培养的不定芽诱导率为36.7%,不定芽培养出现褐化现象,不能形成再生植株;而以子叶-子叶柄为外植体培养获得的植株再生率可达80%。     

提高农杆菌基因转化率方法的研究

通过甘蓝型油菜带柄子叶转化过程中转化受体是否进行预培处理、转化前菌液的对数浓度确定以及合适的再生筛选体系的摸索,研究了提高农杆菌基因转化效率的方法。试验结果表明：转化受体经过MD培养基3d的预培处理,用处于对数生长期OD600为0．6～0．8的菌液稀释至所需浸染浓度,浸染所需时间共培后,转入降低卡那霉素浓度的初筛分化培养基中,再经过后期较高浓度的卡那霉素继代筛选培养,大大提高了转化后卡那霉素抗性绿苗的得率。此研究不仅优化了油菜的转化体系和提高了油菜的转化效率,而且为农杆菌转化其它不同物种的受体材料提供了可指导的借鉴。     

adventitious shoot regeneration from petiole explants of Heracleum candicans wall

Summary A method for adventitious shoot induction from petiole explants of Heracleum candicans is reported. Shoot buds were induced on Murashige and Skoog (MS) medium with 4.4μM 6-benzylaminopurine (BA) and 1.1 μM 2,4-dichlorophen-oxyacetic acid (2,4-D). A wound response in the presence of BA and 2,4-D at the time of culture was necessary for inducing shoot buds. The shoot bud regeneration was significantly influenced by size, type and orientation of explants on the culture medium. These shoot buds developed into 4–5 cm shoots upon transfer to a medium containing 1.1μM BA and 0.5 μM α-naphthaleneacetic acid (NAA). The regenerated shoots formed rooted plantlets on MS medium supplemented with 4.9 μM indole-3-butyric acid (IBA). About 15 plants were established in the field for further evaluation.     

梨叶柄再生不定芽的研究

研究获得了梨品种八月红和水晶的叶柄再生不定芽,不定芽由愈伤组织分化形成。诱导叶柄再生不定芽的适宜培养基为NN69＋IBA0.5mg/L（八月红）或IAA0.5mg/L(水晶）＋TDZ1.0mg/L＋蔗糖30g/L＋琼脂6.0g.。AgNO3浓度在0.1-1.5mg/L范围对八月红梨叶柄再生有促进作用,培养基中附加AgNO30.5mg/L八月红梨叶柄再生效率最高。