我国麻类作物种质资源保护与利用研究进展

总结了我国麻类种质资源在收集保存、繁殖更新、鉴定评价和分发利用等方面的最新进展.10年来,新增麻类种质697份,保存资源数量增至9764份,居世界第1位;繁殖更新麻类资源5343份次,基本解决了麻类资源安全保存和供种等问题;完成农艺性状、经济性状及特性鉴定6543份次,筛选出麻类优异种质296份;向全国50家单位分发种质4296份次,资源利用效率大幅提高.并针对当前存在的问题,提出了下一步工作的明确目标和任务.     

Variety Trial and Pyrolysis Potential of Kenaf Grown in Midwest United States

Kenaf (Hibiscus cannabinus L.) has potential as an annual herbaceous biomass feedstock. It is not typically grown in the American Midwest; however, kenaf may be attractive as an alternative crop for Iowa and the Corn Belt. In this study, seven kenaf varieties were grown in Iowa and evaluated for their productivity. More specifically, our research questions were the following: (1) how do kenaf varieties perform in Iowa for yield? (2) How does fiber morphology and quality differ among varieties and among core and bast fiber? And (3) What potential does kenaf (bast and core) have for producing fuel using fast pyrolysis? Tainung 2, one of the varieties, reached the best yield in Central Iowa over multiple years. Bast kenaf contained 8 % more cellulose and 23 % less hemicellulose than the core but it varied among varieties. Also, regardless of variety, core was composed of 40 % more lignin than bast. Core was found to have higher potential for fast pyrolysis than the bast but its potential was variety-dependent. Overall, kenaf could be grown to diversify Iowa agriculture and provide alternative feedstock to the biofuel industry.     

Carbohydrate components and crystalline structure of organosolv hemp (Cannabis sativa L.) bast fibers pulp

Changes in carbohydrate components and crystalline structure of hemp bast fibers during organosolv pulping were investigated by X-ray diffractometry, FT-IR spectroscopy and high performance liquid chromatography (HPLC). The reasons for defibrillation and beating problems with organosolv hemp bast fiber pulp were investigated with reference to these properties of pulp samples. Hemp bast fibers and organosolv pulp samples had low hemicellulose contents and high cellulose contents. It was found that the disorder parameter of cellulose in hemp bast fibers was very low, when crystalline cellulose ratio was high and the crystalline structure of cellulose in hemp bast fibers was very stable. These properties affected defibrillation and beating of organosolv hemp bast fibers pulp negatively.     

Elucidating the effects of laccase-modifying compounds treatments on bast and core fibers in flax pulp

Laccases in combination with various chemical compounds have been tested with a view to obtain environmental friendly, high‐value paper products from unbleached flax pulp, which is currently being assessed as a raw material for biotechnological innovation. With the aim of better understanding the effects of violuric acid (VA) and p‐coumaric acid (PCA) on flax pulp, changes in the chemical composition of the two major fiber types it contains were assessed. Following classification, the initial pulp was split into two fractions according to fiber size, namely: bast (long) fibers and core (short) fibers. Fiber size was found to significantly influence the properties of pulp and it response to various laccase treatments. The laccase‐PCA treatment substantially increased kappa number (KN) and color in both fiber fractions, which suggests grafting of the phenolic compound onto fibers. On the other hand, the laccase‐VA treatment produced long fibers with a low lignin content (KN = 1.3) and a high brightness (5% points higher than for the control fraction), which testifies to its bleaching efficiency. Both biotreatments produced long fibers containing highly crystalline cellulose and caused HexA removal from global and short fibers. On the other hand, the laccase treatments caused no morphological changes in the fibers, the integrity of which was largely preserved. As shown here, laccase acts as polymerization agent with PCA and as delignification agent with VA; also, the two enzymes systems act differently on bast and core fibers. Biotechnol. Bioeng. 2012;109: 225–233. © 2011 Wiley Periodicals, Inc.     

Morphological changes in woody stem of Prunus jamasakura under simulated microgravity.

When the four-week-old woody stem of Prunus jamasakura was grown under simulated microgravity condition on a three-dimensional clinostat, it bent at growth, and width of its secondary xylem decreased due to the reduction of fiber cell numbers and a smaller microfibril angle in the secondary cell wall, as reported in our previous paper. Gravity induces the development of the secondary xylem that supports the stem upward against the action of gravity. In this study, morphological changes of the tissues and cells were microscopically observed. Disorder was found in the concentric structure of tissues that organize the stem. The radial arrangement of the cells was also disturbed in the secondary xylem, and in the secondary phloem secondary cell walls of the bast fiber cells were undeveloped. These findings suggest that differentiation and development of the secondary xylem and the bast fiber cells are strongly controlled by terrestrial gravity. These tissue and cells functions to support the stem under the action of gravity. Furthermore, clinorotation induced disorder in the straight joint of vessel elements and the lattice-like structure of radial parenchyma cells, which is responsible for water transportation and storage, respectively. Gravity is an essential factor for keeping the division and differentiation normal in woody stem.     

Interspecific hybrids between kenaf ( Hibiscus cannabinus ) and roselle ( H. sabdariffa )

The successful interspecific cross is reported for the first time between kenaf (Hibiscus cannabinus L.), a diploid species (2n=36) and roselle (Hibiscus sabdariffa L.), a tetraploid species (2n=72). Kenaf, grown for its bast fiber and also under investigation as a source of paper pulp, is fast-growing and well adapted to mechanical harvesting, but susceptible to root-knot nematodes. Roselle, also grown for its bast fiber, is slower growing, not well adapted to mechanical harvesting, but certain varieties are resistant to root-knot nematodes. Five hybrid plants were produced from the pollination of 4,445 flowers of kenaf with pollen from roselle; no hybrid plants were produced from 2,655 pollinations made in the reciprocal direction. One line of roselle was the parent of 3 of the 5 hybrids; one line of kenaf was the parent of 2 of these 3. The F₁ hybrids were triploid, and varied in vigor, growth habit and vegetative morphology, but had similar flowers. Two of the F₁ hybrids showed high pollen fertility, apparently as a result of restitution at first meiotic division leading to unreduced spores. These two hybrids each produced a small amount of seed, which gave rise to an F₂ population of 22 plants. The F₂ plants vary in vigor but are morphologically uniform, have thick leaves with mosaic sectors, and are presumably spontaneous allohexaploids. The theoretical possibilities of increasing the percentage of recovery of the F₁ interspecific hybrids and of developing a synthesized hybrid variety useful for bast fiber and paper pulp are discussed. Research done cooperatively by Crops Research Division and Agricultural Engineering Research Division, Agricultural Research Service, U.S. Department of Agriculture (USDA), and the University of Florida Agricultural Experiment Station. Cytological investigations were carried out at the Department of Biological Sciences, Florida State University. Thanks are extended to the many individuals and organizations who supplied material for this study, and to M. Griffin Bell and E. Otho Richey, Agricultural Research Technicians, for their enthusiastic assistance.     

我国麻类资源的多样性及其保护利用对策

在“七五”、“八五”、“九五”研究的基础上,本文论述了我国麻类资源的种类、数量与分布以及保护利用现状等方面的问题,并提出了多样性的可持续发展和利用对策,为今后我国麻类资源的收集、保存、鉴定、创新和利用提供依据。     

Biodegradation of exploded cotton stalk by Bacillus sp.

The exploded bast, branch and stem of cotton stalk were degraded by alkalophilic Bacillus NT-19, with weight losses of 24%, 20% and 14%, respectively, after 14 d. Compared with a white-rot fungus (Phanerochaete chrysosporium), Bacillus NT-19 preferentially degraded the non-cellulose components of cotton stem. The relative degree of crystallinity of bast fibers decreased by 8% and the middle lamella was partially removed from the fiber bundle by the Bacillus.     

从富集液中发掘麻类脱胶果胶酶基因的技术

为了突破传统可培养技术筛选麻类脱胶用果胶酶基因的不足,通过设计不同总DNA提取方法、样品富集方法以及优化PCR反应体系,建立起了一套适合于直接从富集液中发掘麻类脱胶用果胶酶基因的技术。结果表明,震荡培养脱胶时间比静止培养脱胶时间缩短51.5%;通过PowerSoilTMDNA Isolation Kit从第4次富集后的震荡发酵中能提取适合的总DNA;PCR最优反应体系为:总体积为25 ml,Mg2+浓度为2.0 mmol/L,dNTPs浓度为0.2 ng/μl,引物浓度为0.6μmol/L,DNA模板取2.5 ng/μl,Taq聚合酶量为0.8 U。获得的基因序列与已报道的果胶酶基因FJ538208序列高度相似,应用该技术成功地从麻类脱胶富集液中克隆到了果胶酶基因。     

A secondary phloic (bast) fibre-shy (<Emphasis Type="Italic">bfs</Emphasis>) mutant of dark jute (<Emphasis Type="Italic">Corchorus olitorius</Emphasis> L.) develops lignified fibre cells but is defective in cambial activity

Bast fibre development in jute (Corchorus spp.) is a complex process that involves the differentiation of secondary phloic fibres (SPF) from the cambium followed by lignification of the fibre wall. We have identified a unique radiation-induced bast fibre-shy mutant of dark jute (C. olitorius L.), which is concurrently defective in the differentiation of SPF and secondary xylem (wood) but develops lignified fibre cells. It displays the most unusual phenotype with stunted growth and abnormal leaf shape, matures earlier, yields significantly less bast fibres and wood, and produces poorer quality fibres than its parental wild-type. Cambial activities in the mutant and the normal type were monitored by estimating the fibre content that entails the total number of fibre cell bundles (FCBs) in an entire transversal section. The results show that a multi-fold reduction of bast fibre yield in the mutant is related to development-specific loss of cambium function along the length of the stem from to top to bottom. Since lignification of the fibre wall in the mutant is not only normal but also developmentally uniform, cambium function may be unrelated to the lignification process during bast fibre development. Lignin does not influence bast fibre strength and fineness. The architecture of the mostly triangular FCB wedges, which is governed by a balanced growth between radially elongating FCBs and tangentially expanding ray cells due to development-specific activation of the fusiform and ray initials of the cambium, conditions fibre fineness. Our study shows that mutation could specifically impair the cambial activity by rendering those initials that differentiate the SPF and secondary xylem nonfunctional.     

果胶酶在麻类脱胶中的应用及其作用机理

脱胶是麻类产业链中的难题。生物脱胶则是解决麻类加工技术难题的发展方向。果胶酶在生物脱胶中的应用一直是研究的重点。本文通过分析国内外有关果胶酶和产酶微生物在选育、发酵、酶学性质、基因工程与脱胶工艺等方面的研究进展,阐明了果胶酶在麻类脱胶中的作用机理。果胶酶是麻类生物脱胶不能缺少的关键酶之一,但不能独立完成麻类脱胶;根据麻类纤维原料特性,采用基因操作等技术构建复合酶高产菌株是未来的重点研究方向。     

Enzymatic Maceration Mechanism in Biochemical Pulping of Mitsumata (Edgeworthia papyrifera Sieb. et Zucc) Bast

In a comparison of the crude enzyme secreted by the bacterium Erwinia carotovora FERM P-7576 with the corresponding purified overall endo-pectate lyase (endo-PATE) pI (isoelectric point)-isozymes on a basis of equal activity and constitution, the former was found to have higher maceration activity for biochemical pulping of caustic soda-presoaked mitsumata (Edgeworthia papyrifera Sieb. et Zucc) bast than the latter. These results indicate that some additional enzyme (s) other than endo-PATE are required for the maceration. Focusing on the maceration activity, the intensive purification of the crude enzyme was conducted and another maceration factor was successfully isolated, which was identified as endo-pectin lyase (endo-PNTE). The isolated endo-PNTE was found to have a molecular weight of 39,000, pI of 8.2 and a specific activity of 7,911 units/mg. The enzymatic maceration of this bast fiber was concluded to be due only to a concerted action of these two enzymes.     

棉麻纤维作物雄性不育研究进展及展望

棉麻是我国重要天然纤维作物。本文对我国棉麻作物雄性不育的类型、雄性不育的选育及雄性不育的机理等研究进展进行了综述,并讨论了棉麻作物雄性不育研究发展方向与杂种优势利用有关问题,同时提出了雄性不育系选育的思路。     

Pectinolytic Enzymes from Actinomycetes for the Degumming of Ramie Bast Fibers

Actinomycetes isolated from 10 different soil and compost samples were screened for production of pectinolytic enzyme activities when grown on pectin-containing solid and liquid media. Pectinolytic enzymes, detected by using plate diffusion tests with a medium containing ramie (Boehmeria nivea) plant material as the sole carbon source, were mainly pectate lyases, but low activities of pectinesterases were also observed. Polygalacturonases and polymethylgalacturonases were not produced. Multiple forms of pectate lyases were detected in the culture supernatants of some of the strains by using the zymogram technique of isoelectric focusing gels. Xylanolytic and cellulolytic activities were always found to be associated with pectinolytic activities. None of the pectinolytic enzymes were produced in a medium with glucose as the sole carbon source. Treatment of ramie bast fibers with crude enzyme preparations from a selection of strains showed a good correlation between the pectate lyase activity applied and the degumming effect, resulting in good separation of the bast fibers.     

In vitro regeneration and optimization of conditions for Agrobacterium mediated transformation in jute, Corchorus capsularis

Jute is a crop of commercial importance that is widely cultivated for its bast fiber production but susceptible to many diseases that results in major economic loss. New genes can be introduced into this plant through Agrobacterium mediated genetic transformation for its genetic improvement, which is dependent on the availability of suitable in vitro techniques. An efficient regeneration system has been developed for in vitro culture of jute (Corchorus capsularis) from the distal cut ends of cotyledonary petioles. High frequency shoot regeneration was obtained on Murashige and Skoog (MS) nutrient agar medium supplemented with 0.5 mg/l NAA, 0.5 mg/l BAP and 36 g/l sucrose. On transfer to soil, the regenerated plantlets survived and appeared to be morphologically similar to the normal seed-grown plants. They developed pods and set fertile seeds. Histological analysis revealed de novo origin of shoot buds in the in vitro cultured cotyledonary petioles. Parameters affecting transformation were optimized by assaying GUS activity in these regenerable tissues after cocultivation with Agrobacteria. These tissues appear to be susceptible for infection and transformation by Agrobacterium carrying uid (GUS INT) and nptII genes, as well as shoot multiplication. The cells at the cut end of the petioles were found competent to take up the DNA, which was monitored by transient GUS gene expression. EHA105 at 0.3 O.D and LBA4404 at 0.5 O.D were found to be compatible in giving optimal levels of transient GUS expression.     

Structural characterization of tissue-specific galactan from flax fibers by 1H NMR and MALDI TOF mass spectrometry

A high-molecular-mass polysaccharide galactan (M 2000 kDa) was isolated from flax at the stage of cell wall thickening of the bast fiber development. The polymer structure was studied by ¹H NMR spectroscopy and MALDI TOF mass spectrometry. It is built up of Gal (59%), Rha (15%), GalA (23%), and Ara (3%) residues. The galactan backbone consists of successively alternating monomer disaccharide units (→ 4GalA1 → 2Rha1 →)_n and is similar in its structure to the backbone of rhamnogalacturonan-1 (RG-I). Rhamnose residues bear in position 4 β-(1 → 4)-galactose side chains of various lengths with a polymerization degree of up to 28 or higher. A part of the side chains have branchings.