Comparison of Stevia plants grown from seeds,cuttings and stem-tip cultures for growth and sweet diterpene glucosides

The growth and sweet diterpene glucosides of Stevia plants propagated by stem-tip cultures were compared with those of the control plants propagated by seeds. There was no significant difference between the two groups both in growth and in chemical composition. As for the contents of sweet diterpene glucosides, however, the clonal plants showed significantly smaller variations than the sexually propagated plants; they were almost as homogeneous as the plants propagated by cuttings. These results suggest that the clonal propagation by stem-tip culture is an effective method of obtaining a population of uniform plants for the production of sweet diterpene glucosides.     

Application of bioreactor systems for large scale production of horticultural and medicinal plants

Automation of micropropagation via organogenesis or somatic embryogenesis in a bioreactor has been advanced as a possible way of reducing costs. Micropropagation by conventional techniques is typically a labour-intensive means of clonal propagation. The paper describes lower cost and less labour-intensive clonal propagation through the use of modified air-lift, bubble column, bioreactors (a balloon-type bubble bioreactor), together with temporary immersion systems for the propagation of shoots, bud-clusters and somatic embryos. Propagation of Anoectochilus, apple, Chrysanthemum, garlic, ginseng, grape, Lilium, Phalaenopsis and potato is described. In this chapter, features of bioreactors and bioreactor process design specifically for automated mass propagation of several plant crops are described, and recent research aimed at maximizing automation of the bioreactor production process is highlighted.     

Plant regeneration from shoot callus of rosewood (Dalbergia latifolia Roxb.)

In vitro propagation of trees using cell, tissue and organ culture is a fast emerging area. We report here the clonal propagation of Indian rosewood (Dalbergia latifolia Roxb.) from shoot callus cultures of 5 year old trees. Bud regeneration was obtained on MS media supplemented with BA and NAA. About 35% of the cultures showed organogenesis. Shoots measuring about 3–5 cm can be excised and rooted in White's medium supplemented with 1–2 mg/L IAA. Rooted plants were successfully established in soil.Abbreviations BA Benzyladenine - CM Coconut milk - 2,4-D 2,4 dichlorophenoxyacetic acid - IAA Indoleacetic acid - IBA Indolebutyric acid - K Kinetin - NAA Naphthaleneacetic acid - PVP-360 Polyvinyl pyrrolidone     

The role of thin cell layers in regeneration and transformation in orchids

Thin cell layers (TCLs) offer a simple yet effective protocol that has contributed to major advances in clonal micropropagation of orchids. TLCs have been successfully used for protocorm-like body (PLB) and callus induction in Aranda, Coelogyne cristata, Cymbidium spp., Dendrobium spp., Doritaenopsis, Paphiopedilum, Renanthera, Rhynchostylis, Spathoglottis, and Xenikophyton. TCLs have also been a bulwark for genetic transformation studies of select genera. This review takes an in-depth look at how TCLs have been employed in orchid biotechnology and provides in-depth protocols that will allow for the generation of PLBs using TCLs. As PLBs in orchids are deemed somatic embryos, these will be useful for large-scale mass propagation in bioreactors or for long-term storage as synthetic seeds.     

Sexual vs. vegetative reproduction in relation to forest dynamics in the understorey shrub,Hydrangea paniculata (Saxifragaceae)

In the forest understorey, shrubs usually reproduce vegetatively rather than sexually, but the relative contribution of these two reproductive modes may vary with temporal changes in environmental conditions (e.g., light, substrates of forest floor) that are closely related to forest dynamics. To evaluate the occasional changes in reproductive modes of the clonal understorey shrub Hydrangea paniculata, the reproductive characteristics (i.e., flowering, seedling establishment, vegetative propagation, reproductive size and age) were investigated in four different developmental stages in a Japanese beech forest (early gap, EG; late gap, LG; building, BU; mature, MA). Flowering individuals occurred only in EG and LG, and a much greater number of seedlings was observed in both EG and LG than in BU and MA, mainly because canopy gaps provided sufficient light for flowering and suitable substrates (fallen trees and exposed mineral-soil) for seedling establishment. The flowering individuals originated from plants that had persisted in the shaded understorey until gap formation. In contrast to sexual reproduction, clonal fragmentation increased with forest development in the order LG, EG, BU, MA. This is because, in later stages of forest dynamics (BU and MA), large individuals, some of which had previously flowered in gap stages, were layered on the forest floor and subsequently produced a substantial number of clonal fragments by separation of the buried branches from the main stems which had decayed. This resulted in a large number of clonal fragments originating from a single mother plant. These results suggest that the reproductive modes of H. paniculata is strongly influenced by the changes in environmental conditions with respect to the dynamics of canopy trees. Reproduction from seed in gap stages, despite their short period, provide new genets in established populations, whereas vegetative propagation via fragmentation in closed-canopy stages enhance the stability of the population until the next disturbance.     

Propagation of fern (Nephrolepis) through tissue culture

Rapid clonal propagation in three stolon bearing species of Nephrolepis was achieved by tissue culture methods. Explants from young stolons were grown on B5 (Gamborg et al. 1968) medium supplemented with indolebutyric acid where they produced several leaf primordia. These leaf primordia were isolated and grown into entire plantlets. An overall multiplication factor of 30–40 was attained within three months.     

Selection of yeast able to produce ethanol from glucose at 40° C

Summary A total of 55 yeast strains selected from 7 genera known to ferment carbohydrates to ethanol were screened for their ability to ferment glucose to ethanol in shaken flask culture at 37°, 40° and 45°C. Yields of more than 50% of the theoretical maximum were obtained with 28 strains at 37°C, but only 12 at 40°C. Only 6 could grow at 45°C, but they produced poor yields. In general Kluyveromyces strains were more thermotolerant than Saccharomyces and Candida strains, but Saccharomyces strains produced higher ethanol yields. The 8 strains with the highest yields at 40°C were evaluated in batch fermentations. Three of these, two Saccharomyces and one Candida, were able to meet minimum commercial targets set at 8% (v/v) ethanol from 14% (w/v) glucose at 40°C.     

Interspecific variation in clonality in temperate lianas revealed by genetic analysis: Do clonal proliferation processes differ among lianas?

Lianas are important components of forest communities with a considerable impact on overall forest structure and function. Lianas are characterized by extensive clonal reproduction on the forest floor, which is important for their establishment and growth. Previous studies have suggested that clonal reproduction strategies vary substantially among liana species; however, few studies have quantitatively evaluated the clonality strategy in multiple co-occurring liana species. The primary objective of the present study was to evaluate the relative contribution of clonal reproduction and to understand the clonal proliferation processes in co-occurring liana species by assessing both small stems on the forest floor and mature stems that climbed trees. The clonal reproduction strategy in four common liana species (stem twiner: Wisteria floribunda; root climbers: Schizophragma hydrangeoides, Euonymus fortunei and Rhus ambigua) in a 6-ha plot and a belt transect within an old-growth temperate forest in central Japan was evaluated using genetic analysis. The contribution of clonal reproduction was smaller in root climbers than in W. floribunda. All W. floribunda genets with small ramets in the understory had genetically identical ramets that climbed trees, whereas few such ramets were found in root climbers. This indicates that W. floribunda mature ramets laterally produce small ramets via clonal proliferation, whereas seedlings of root climbers grow horizontally to climb trees. The results indicate that the clonal reproduction processes differ greatly among lianas and the clonal growth in lianas plays a contrasting role in their life-history strategy.     

The botanical diversity in the Ayawasi area, Irian Jaya, Indonesia

In the karst-dominated Ayawasi area (Bird's Head peninsula), the botanical diversity and its relation to soil and geological substratum were studied. An inventory in 22 plots of 0.1 ha was made of all plants (1945) with a dbh 10 cm (mainly trees). Myrtaceae, Burseraceae, and Euphorbiaceae were the most frequent families (considering relative number of individuals), whereas Myrtaceae, Lauraceae, and Meliaceae were most species-rich. The most frequent genera were Syzygium, Haplolobus, and Lithocarpus, and most species-rich were Syzygium, Garcinia, Elaeocarpus, and Pouteria. The most frequent species were Anisoptera thurifera, Tristaniopsis ferruginea, and Gymnacranthera farquhariana var. zippeliana. Species richness was greater in plots in mixed forest (38–57 species, average 48) than in limestone forest (26–42 species, average 33) and secondary forest (21–46 species, average 34). Some very common species, such as Xanthophyllum novoguineense (Polygalaceae) and Macaranga suwo (Euphorbiaceae), were hitherto herbarium rarities, known from very few collections only. Species dominating earlier investigated forests elsewhere in the Bird's Head Peninsula range from being less important to absent in the presently investigated forest. Explanatory factors for this phenomenon are variation due to the geographical distance, the high beta-diversity of tropical forests in general, habitat differences, and differences in research methods, in particular in their scale.     

A parenchymatic medium solidifier for plant in vitro culture

A new material for the solidification of liquid culture media was prepared from plant parenchyma tissues by mechanical subdivision, solute extration and dessication from ethanol. It is suitable for in vitro culture and propagation of callus as well as shoot tip cultures. The following plant materials have been grown by means of the new medium solidifier: shoot cultures of Betula pendula Roth, Gerbera jamesonii H. Bolus ex Hook and Floribunda rose "Triumph", callus tissues of Daucus carota L. and Chenopodium album L. The new solidifying material has special advantages over agar for application in the rooting phase of in vitro propagation.Abbrevations PMS parenchymatic medium solidifier - MS Murashige and Scoog's medium - IAA Indole-3-acetic acid - B biotin - K kinetin - 2,4-D 2,4-dichlorophenoxyacetic acid - ch caseine hydrolysate     

天山林区土壤真菌多样性及其群落结构

土壤真菌群落结构对森林生态系统功能的维持具有重要作用,目前对天山林区土壤微生物的种类和群落结构了解甚少。为了解天山不同植被类型下土壤真菌的群落动态及优势菌属,使用Illumina MiSeq高通量测序技术,研究天山林区根际土与非根际土中真菌群落组成及多样性。结果表明:(1)对有效序列进行OTU聚类(operational taxonomic unit)后共得到14121个OTUs,经注释划分为7个门、33个纲、109个目、255个科、444个属、677个种;(2)子囊菌门(Ascomycota)和担子囊菌门(Basidiomycota)是天山植物的优势菌门,灌丛中相对丰度较高的有帚枝霉属(Sarocladium)、鬼笔属(Lysurus)、Microidium;云杉林中相对丰度较高的属有镰刀属(Fusarium)、赤霉属(Gibberella)、丝盖伞属(Inocybe);(3)灌丛与云杉林土壤真菌的群落结构和丰富度有显著差异,灌丛土壤真菌的多样性和丰富度更高,云杉林中阴坡的土壤真菌丰富度较高而阳坡和林窗较低;(4)丝盖伞属(Inocybe)、被孢霉属(Mortierella)、赤霉属(Gibberella)、镰刀属(Fusarium)与云杉的生长可能具有密切的关系。本文推测,根际土壤真菌的多样性和丰富度较低可能是导致云杉幼苗成活率低等更新障碍的问题。     

The distribution of mosquitoes (Diptera,Culicidae) in the Republic of Azerbaijan

The mosquito fauna in the territory of the Republic of Azerbaijan comprises 24 species from 7 genera. The dominant species are Anopheles sacharovi, Culex pipiens, Aedes caspius, and Ae. geniculatus in the forest area, and Coquillettidia richiardii in the lowlands, where there are swamps overgrown with reeds.     

Evergreen swamp forest in Cambodia: floristic composition,ecological characteristics,and conservation status

As part of recent field studies, a hitherto undescribed type of evergreen freshwater swamp forest was discovered in Stung Treng Province, Cambodia. The swamp forest occurs in at least six disjunct localities and is dominated by hydrophytic trees (Eugenia spp., Ficus spp., Litsea spp., Macaranga triloba, Myristica iners and Pternandra caerulescens). Although these same genera also occur in upland forests, most are represented by different species in the swamps. Livistona saribus emerges from the canopy as an indicator species of this vegetation type while dense stands of other palms (Calamus, Areca, Licuala) and sporadic, dense populations of tree ferns (Cibotium barometz) dominate the understory. Pneumatophores, stilt roots, and aerial roots characterize the hydrophytes. The floristic composition indicates that the forest type is distinct compared to other swamp forests described from the region and worthy of protection based on its rarity and ecological uniqueness.     

粤东桥溪村风水林群落特征初探

在粤东梅州市桥溪村风水林设立样方,对其乔木层、灌木层和草本层植物进行调查,分析该风水林的群落特征及植物多样性。结果表明:该风水林3 000 m2的样方内,共有维管植物67种,隶属于37个科54个属,其中蕨类植物4科4属4种,裸子植物3科3属3种,被子植物30科47属60种。群落分布型以热带性分布占优势,热带属所占比例为74.08%。群落主要优势科为樟科、壳斗科、金缕梅科,优势种为细柄阿丁枫、刺毛杜鹃、鼠刺、阿丁枫。群落为常绿阔叶林,生活型以高位芽为主,占73.13%,其中又以中高位芽类型最多,约占43%。乔木层可分为三层,但以株高6~9.9 m的个体数为最多;藤本的比例高达17.91%。马尾松、杉木、细柄阿丁枫以及阿丁枫都缺少幼苗贮备,其种群属于衰退状态;而刺毛杜鹃、越南山龙眼幼苗贮备较充足,且刺毛杜鹃种群是典型的增长型种群。该风水林群落比周边其他群落有较高的物种丰富度、植物多样性,且物种分布较为均匀,种间相遇率较大。在群落不同层中,物种丰富度、Margalef指数、Shannon-Winer指数、Simpson指数、种间相遇机率乔木层均为最高,均匀度指数以灌木层较高,草本层的优势度指数最高。桥溪村风水林与粤东和华南地区的其他常绿阔叶林有很大的相似性。该风水林在粤东地区是一种典型的地带性森林,其树种组成是经过长时间对当地环境适应而形成的,具有稳定性和多功能性,对其研究可为华南地区的植物资源保护、生态公益林的保护和营造提供科学依据。     

Effectiveness of ph gene in inducing homoeologous chromosome pairing in agrotricum

Summary We observed pairing, when the ph gene was present, between wheat (Triticum aestivum L. em. Thell.) chromosome 4B, and an Agropyron intermedium (Host) Beauv. chromosome (Ai) carrying a gene resistant to wheat streak mosaic (WSM). In a monosomic addition polyhaploid [2n = 22 = 19' + 5B' (ph) + 4B' + Ai'], we recorded an average of 4.1 bivalents and 0.3 trivalents per cell. Induced homoeologous pairing was most effective when both 5B chromosomes carrying ph gene were present. Our data suggest that chromosome 4B of wheat and the Agropyron chromosome (Ai) carrying a gene for resistance to WSM are homoeologous and that it is possible to use either ph mutant or nullisomic 5B stock to induce genetic recombination between the two chromosomes.Contribution No. 1657-j, Kansas State Agric. Expt. Sta., Manhattan, KS. The research is partially supported by a grant from Kansas Wheat Commission     

Lactic acid bacteria active during the fermentation of wheat silage in small scale silos

Summary Wheat was ensiled and periodically analyzed for lactic acid bacteria present. Initially Lactobacillus plantarum, Leuconostoc mesenteroides, Lactobacillus cellobiosus and Streptococcus lactis predominated. After two to four days enterococci including S. faecium and S. bovis were present in high populations as well as Lactobacillus plantarum. It was concluded that mixed populations of enterococci and L. plantarum are active in the successful fermentation of wheat silage.     

Gypsy/Ty3-class retrotransposons integrated in the DNA of herring,tunicate, and echinoderms

Eight new examples of retrotransposons of the Gypsy/Ty3 class have been identified in marine species. A 525-nt pol gene-coding region was amplified using degenerate primers from highly conserved regions and has extended the range of recognition of Gypsy/Ty3 far beyond those previously known. The following matrix shows the percentage AA divergence of the translations of this segment of the pol gene coding region. Spr2 Strongylocentrotus purpuratus, sea urchin 39 Por2 Pisaster ochraceus, starfish 46 45 Cprl Clupea pallasi, herring 51 52 41 Cirl Ciona intestinalis, tunicate bar52 49 49 55 P. orchraceus, starfish 55 60 60 62 62 Spr3 S. purpuratus, sea urchin 55 61 60 63 61 24 Tgrl^* Tripneustes gratilla, sea urchin 56 61 60 63 58 26 27 Lvrl^* Lytechinus variegatus, sea urchin 57 62 60 64 62 27 10 29 Sprl^* S. purpuratus 58 61 62 65 61 15 27 30 31 Spr4 S. purpuratus 72 72 74 75 72 73 72 72 73 72 Por3 P. ochraceus The underlines separate three groups of retrotransposons that can be recognized on the basis of this amino acid sequence. The new upper group shows surprising amino acid sequence similarity among members from the DNA of herring, sea urchin, starfish, and a tunicate. For example, the herring element differs by only 41 % from the Ciona element and 46% from the sea urchin element. The group between the lines includes members close to previously known elements (marked by asterisks) and has so far been found only in sea urchins. The two upper groups differ from each other by 55–60% and yet members of both groups (e.g., Sprl and Spr2) are integrated into the DNA of one species-S. purpuratus. Below the lower underline is listed the only known representative of a very distant group, which occurs in starfish DNA. In spite of large divergence, amino acid sequence comparisons indicate that all of the elements shown in the array are members of the LTR-containing class of retrotransposons that includes Gypsy of Drosophila and Ty3 of yeast. Of all known mobile elements this class shows the closest sequence similarity to retroviruses and has the same arrangement of genes as simpler retroviruses.Correspondence to: R.J. Britten     

Sexual reproduction, clonal diversity and genetic differentiation in patchily distributed populations of the temperate forest herb Paris quadrifolia (Trilliaceae)

Clonal plant species have been shown to adopt different strategies to persist in heterogeneous environments by changing relative investments in sexual reproduction and clonal propagation. As a result, clonal diversity and genetic variation may be different along environmental gradients. We examined the regional and local population structure of the clonal rhizomatous forest herb Paris quadrifolia in a complex of forest fragments in Voeren (Belgium). Relationships between population size (the number of shoots), shoot density (the number of shoots per m²) and local growth conditions were investigated for 47 populations. Clonal diversity and genetic variation within and among 19 populations were investigated using amplified fragment length polymorphism markers. To assess the importance of sexual reproduction, seed set, seed weight and germination success were determined in 18 populations. As predicted, local growth conditions largely affected population distribution, size and density of P. quadrifolia. Populations occurring in moist and relatively productive sites contained significantly more shoots. Here, shoots were also much more sparsely distributed compared to populations occurring in dry and relatively unproductive sites, where shoots showed a strongly aggregated distribution pattern. Clonal diversity was relatively high, compared with other clonal species (G/N ratio = 0.43 and Simpson’s D=0.81). Clonal diversity significantly (P<0.01) decreased with increasing shoot density while molecular genetic variation was significantly (P<0.01) affected by population size and local environmental conditions. Lack of recruitment and out-competition of less-adapted genotypes may explain the decreased genetic variation in dry sites. Analysis of molecular variance revealed significant genetic variation among populations (Φ _ST=0.42, P<0.001), whereas pairwise genetic distances were not correlated to geographic distances, suggesting that gene flow among populations is limited. Finally, the number of generative shoots, the number of seeds per fruit and seed weight were significantly and positively related to population size and local growth conditions. We conclude that under stressful conditions populations of clonal forest plant species can slowly evolve into remnant populations characterized by low levels of genetic variation and limited sexual reproduction. Conservation of suitable habitat conditions is therefore a prerequisite for effective long-term conservation of clonal forest plant species.