Transmission of a New Mycoplasma-Like Organism (MLO) from Cuscuta odorata (Ruiz et Pav.) to Herbaceous Plants and Attempts to its Elimination in the Vector

A new MLO-type, originating from a holoparasite plant Cuscuta odorata (Ruiz et Pav.) causing stunting and reduction of flower- and leaf size on Catharanthus roseus (L.) G. Don. (HEINTZ 1986) was transmitted to Apium graveolens L., Plantago major L., Bellis perennis L. and Cirsium japonicum hybrid. The observed symptoms on the test plants probably caused by the MLO have not yet been described in the literature. The symptomatology on these herbaceous plants gives further data in order to classify the MLO as a new one which is named Guscuta latent MLO (Cl-MLO). Attempts to transmit the pathogens by the leafboppers Euscelidius variegates (Kirschbaum) and Euscelis lineolatus (Brullé) failed. It also was impossible to elimmate the MLO completely from Cuscuta odorata by heat treatment and antibiotic application. However, we succeeded in eliminating the pathogens from Catharanthus roseus by heat treatment.     

Occurrence of Anomalous Mycoplasma-like Organisms in Grapevine Yellows-diseased Phloem

Pathological changes in Vitis vinifera cv. Caveccia phloem from leaves showing symptoms of a flavescence doreé-like disease consisted of obliteration, necrosis and collapse of the sieve elements and associated companion cells, and excessive callose accumulation in lateral sieve areas and sieve plates of apparently normal mature sieve elements. Unusual structures, also found in degenerate sieve elements of diseased leaf vein specimens, were strongly electron-dense and bounded by a unit membrane or an electron-transparent border, and considered to be senescent forms of mycoplasma-like organisms. The significance of these findings in relation to possible host responses to the yellows pathogen is discussed.     

Occurrence of Anomalous Mycoplasma-like Organisms in Grapevine Yellows-diseased Phloem

Pathological changes in Vitis vinifera cv. Caveccia phloem from leaves showing symptoms of a flavescence doreé-like disease consisted of obliteration, necrosis and collapse of the sieve elements and associated companion cells, and excessive callose accumulation in lateral sieve areas and sieve plates of apparently normal mature sieve elements. Unusual structures, also found in degenerate sieve elements of diseased leaf vein specimens, were strongly electron-dense and bounded by a unit membrane or an electron-transparent border, and considered to be senescent forms of mycoplasma-like organisms. The significance of these findings in relation to possible host responses to the yellows pathogen is discussed.     

An Anatomical Study of Rhizome Bud Formation Induced by Paclobutrazol and Adventitious Root Formation in In Vitro Cultures of Lapageria rosea (Ruiz et Pav.)

An anatomical study was made of bud dimorphism in in vitro shootcultures of Lapageria rosea cv. Nashcourt, utilizing the presenceand absence of the gibberellin-biosynthesis inhibitor paclobutrazol(10 µM) in the medium to control the development of axillarybuds. Patterns of axillary bud development differed betweenthe aerial pattern of shoot extension (in the absence of paclobutrazol)and rhizome bud formation (in the presence of paclobutrazol),with respect to planes of cell division, cell expansion andthe formation of adventitious root primordia. These differencesare examined and discussed. Lapageria rosea cv. Nashcourt, Chilean Bellflower, rhizome bud, paclobutrazol, gibberellin biosynthesis inhibitor, micropropagation     

Phytochemical Investigation of Male and Female Hedyosmum scabrum (Ruiz & Pav.) Solms Leaves from Ecuador

This article reports the chemical composition of the essential oils obtained by hydrodistillation of male and female H. scabrum fresh leaves. The essential oils, HSMO and HSFO, respectively, were analyzed by GC/MS and GC‐FID. A total of 93 components were detected, accounting for 94.8% and 95.3% of HSMO and HSFO, respectively. The prevalent constituents of HSMO were pinocarvone (13.1%), d ‐germacren‐4‐ol (12.6%), 1,8‐cineole (10.8%), α‐pinene (6.4%), and β‐pinene (4.8%), whereas the major components of HSFO were 1,8‐cineole (20.5%), linalool (16.5%), α‐pinene (15.0%), β‐pinene (6.4%), and sabinene (6.3%). The different enantiomeric distribution of β‐pinene, sabinene, limonene, linalool in the two oils, was determined. The non‐volatile esters of p‐coumaric and ferulic acids with borneol ( 1 and 4 ), cis‐chrysanthenol ( 2 and 5 ), and cis‐pinocarveol ( 3 and 6 ) were identified in the leaves after basic hydrolysis and analysis of the NMR spectra of the free acids, and GC/MS spectra of the monoterpene alcohols, respectively. Compounds 2 , 3 , 5 , and 6 have been found in nature for the first time. These findings demonstrated that, from a chemical point of view, male and female individuals of H. scabrum collected in Ecuador seem quite differentiated between each other and from samples of the same species growing in Bolivia and in Peru.     

Morphology of floral papillae in Maxillaria Ruiz & Pav. (Orchidaceae)

BACKGROUND AND AIMS: The labellar papillae and trichomes of Maxillaria Ruiz & Pav. show great diversity. Although papillae also occur upon other parts of the flower (e.g. column and anther cap), these have not yet been studied. Labellar trichomes of Maxillaria are useful in taxonomy, but hitherto the taxonomic value of floral papillae has not been assessed. The aim of this paper is to describe the range of floral papillae found in Maxillaria and to determine whether papillae are useful as taxonomic characters. METHODS: Light microscopy, histochemistry, low-vacuum scanning and transmission electron microscopy. KEY RESULTS: A total of 75 taxa were studied. Conical papillae with rounded or pointed tips were the most common. The column and anther cap usually bear conical, obpyriform or villiform papillae, whereas those around the stigmatic surface and at the base of the anther are often larger and swollen. Labellar papillae show greater diversity, and may be conical, obpyriform, villiform, fusiform or clavate. Papillae may also occur on multiseriate trichomes that perhaps function as pseudostamens. Labellar papillae contain protein but most lack lipid. The occurrence of starch, however, is more variable. Many papillae contain pigment or act as osmophores, thereby attracting insects. Rewards such as nectar or a protein-rich, wax-like, lipoidal substance may be secreted by papillae onto the labellar surface. Some papillae may have a protective role in preventing desiccation. Species of diverse vegetative morphology may have identical floral papillae, whereas others of similar vegetative morphology may not. CONCLUSIONS: Generally, floral papillae in Maxillaria have little taxonomic value. Nevertheless, the absence of papillae from members of the M. cucullata alliance, the occurrence of clavate papillae with distended apices in the M. rufescens alliance and the presence of papillose trichomes in some species may yet prove to be useful.     

Depressed Pollination of Lapageria rosea Ruiz et Pav. (Philesiaceae) in the Fragmented Temperate Rainforest of Southern South America

We studied the pollination and reproductive success in continuous and fragmented populations of Lapageria rosea, a self-compatible plant endemic to temperate forests of Chile. Pollinator abundance, visitation rates, flower abundance, nectar volume and concentration, pollen germination and fruit and seed production, were compared between continuous forest of 145 ha and four forest fragments of 6, 3, 3, and 1 ha respectively, surrounded by mature pine plantations of Pinus radiata. Flower abundance was lower in three out of four forest fragments relative to continuous forest. Nectar volume and sugar concentration did not differ between flowers in the two habitats. Pollinators of L. rosea, the hummingbird Sephanoides sephaniodes and bumblebee Bombus dahlbomii were less abundant and visited flowers of L. rosea at lower rates in fragments than in continuous forest. In addition, in vitro rates of pollen germination were lower for flowers in forest fragments. The number of seeds per fruit was also lower in forest fragments. We suggest that fragmentation affects the reproductive success of L. rosea, lowering the total numbers of seeds produced and possibly compromising long term persistence of fragmented populations.     

Mycoplasma-like Organisms in Phloem Elements of Ammobium alatum

Using transmission electron and fluorescent microscopes, Mycoplasma-like organisms (MLOs) were found in phloem cells of stems and leaves of Ammobium alatum. The diameter of these organisms ranged from 0.12–0.73 μm and averaged 0.4 μm. Symptoms induced by MLOs included chlorosis and reddening of leaves and winged stems, plant stunting and flower phyllody. This is the first report of MLOs associated with disease symptoms in A. alatum.     

Maintenance of MLOs (Mycoplasma-like Organisms) on Populus alba Micropropagation

Populus alba plantlet micropropagation has been used for maintaining MLOs more than three years in samples collected from infected trees in Paris. Symptoms were observed on plantlets obtained from subcultures of the apical, middle and basal parts of the stems, and from the roots. Fluorescent microscopy failed to detect MLOs in the apical part of the plantlets and showed that they increased near the roots. Electron microscopy confirmed their presence. Some root sieve tubes were completely packed with MLOs. The sensitivity of the two methods used, subculturing and microscopy, for detection of MLOs is discussed. The symptoms remained for one year in plants regenerated from diseased plantlets and grown in the greenhouse. Then they started to disappear.     

Phenolic constituents of leaves from Persea caerulea Ruiz & Pav; Mez (Lauraceae)

The chemical investigation of the ethanolic extract from the leaves of Persea caerulea led to the isolation of flavonoids, coumarins and three steroidal type compounds. Based on ESI-MS, UV, IR, GC-MS and ¹H and ¹³C NMR data analysis, the structures of ten isolated compounds were identified as: quercetin (1), kaempferide-3-O-α-l-rhamnopyranoside (2), kaempferol-3-O-α-l-arabinofuranoside (3), quercetin-3-O-α-l-rhamnopyranoside (4), quercetin-3-O-β-glucoside (5), scopoletin (6), isofraxidin (7) campesterol (8), stigmasterol (9) and β-sitosterol (10). In the current research, the isolated compounds 1–9 are reported for the first time in the species Persea caerulea.     

Ultrastructural Visualization of Glucide Determinants in Membranes of Mycoplasma-like Organisms

Periodic acid-thiocarbohydrazide-silver proteinate (PATAg) reaction for poiysaccharide localization was performed on ultrathin sections of Spurr resin-embedded tissues of Physostegia virginina and Catharanthus roseusknown to be infected by mycoplasma-like organisms (MLO). Electron microscopy of PATAg-treated sections revealed heavy silver deposition on hmiting membranes of all MLO. It was not possible to detect differences m silver deposition within the multi stratified membrane structure because of masking by silver-grain deposition. Silver deposition was not found in the cytoplasmic region of the MLO. The results indicate the presence of glucide determinants only in the limiting membrane of the MLO. The significance of this finding is discussed.     

Detection of Mycoplasma-like Organisms in Infected Potato by Electron Microscopy

By using electron microscopy pleomorphic mycoplasma-like bodies were observed only in the phloem cells of the field infected potato plants showing purple top roll symptoms. The bodies surrounded by unit membranes were 50–300 nm in diameter.     

粗毛牛膝菊对呼和浩特植物多样性的影响

【目的】粗毛牛膝菊为内蒙古地区新发现的一种入侵植物,在呼和浩特的入侵范围不断扩大、种群数量日益增加。了解其入侵后对本地植物多样性产生的影响,可为及时防控提供预警与理论依据。【方法】通过样方调查法结合数理统计,分析21个样地中植物物种丰富度指数(S)、Simpson指数(D)、Shannon-Wiener指数(H)和Pielou指数(J)的差异。【结果】入侵样地中共有73种植物,隶属25科55属,其中菊科种类最多,共18种,占总种数的24.66%,禾本科、藜科种类次之,分别占17.81%和5.48%。粗毛牛膝菊入侵地中,其重要值(IV)呈现不同程度的增加,表现为IV随着相对密度、相对频度、相对盖度的增大而增大。与对照组相比,粗毛牛膝菊入侵地中的S、H、D和J指数均下降,下降最大幅度分别为65.2%、78.6%、62.2%和72.6%,其中H指数下降幅度最大。重要值与各多样性指数(S、D、H和J)间的关系表现为:随着粗毛牛膝菊重要值的增大,各多样性指数均下降,当IV0.551时,H指数显著降低(P0.05);当IV1.10时,H和J指数极显著降低(P0.01),呈明显的负相关。【结论】粗毛牛膝菊的入侵已对呼和浩特的植物多样性造成了威胁,应及时展开科学的防控措施。     

The Occurrence of Vascular Cavities and Specialized Parenchyma Cells in the Roots of Cool-season Legumes

The seeds of 20 legume species were grown in the greenhouse or in growth chambers at different temperatures. Under warm temperature conditions (above 15 °C), six species, pea (Pisum sativum), broadbean (Vicia faba), chickpea (Cicer arietinum), lentil (Lens culinaris), wild lupine (Lupinus latifolius), and soybean (Glycine max), formed cavities in the vascular cylinder of their primary roots, which in turn became filled by the ingrowth of specialized parenchyma cells (SP cells). When these species were grown at low temperature (below 15 °C), however, a “normal” vascular cylinder formed in the primary roots with late-maturing metaxylem vessel members differentiating in the center. These species were all cool-season legumes except soybean, a warm-season legume, which sometimes also formed cavities and SP cell ingrowths. The occurrence of cavities and SP cells therefore was restricted to the cool-season legumes (except soybean) when they were grown under warm temperature conditions. The position and size of cavities varied among these species. Pea and broadbean usually formed large, axially elongated cavities in the central vascular cylinder, or in the xylem poles. Others formed smaller cavities of various lengths.     

Triterpenoids from Rosa odorata Sweet var. gigantea (Coll.et Hemsl.) Rehd.et Wils and their chemotaxonomic significance

Thirty-three reported compounds were obtained for the first time from Rosa odorata Sweet var. gigantea (Coll.et Hemsl.) Rehd. et Wils and were all identified as triterpenoids. The structure of these compounds was determined by physicochemical constants and spectral analyses (NMR, MS). This is the first report on four compounds (7, 9, 10 and 22) from the family Rosaceae and thirteen compounds (2, 3, 4, 11, 17, 19, 20, 23, 24, 26, 29, 31 and 33) from the genus Rosa. Finally, the chemotaxonomic significance of these compounds is discussed.