scholarly journals The features of xylem tracheary elements in some herbaceous members of the family Convolvulaceae Horan.

Turczaninowia ◽  
2021 ◽  
Vol 24 (3) ◽  
pp. 129-137
Author(s):  
Yevgeniya V. Goremykina ◽  
Aleksandra D. Azaryan ◽  
Esong Linda Akime ◽  
Kseniya Y. Leshchina
Keyword(s):  
Parasitic Plants ◽  
Tracheary Elements ◽  
Convolvulus Arvensis ◽  
Climbing Plants ◽  
Conducting Tissue ◽  
The Family ◽  
Cuscuta Campestris ◽  
Order Of Magnitude ◽  
Parasitic Lifestyle ◽  
Calystegia Sepium

Numerous narrow xylem tracheary elements (tracheids and vessels) are present in liana stems, along with a few wide vessels that perform the main water-conducting function. This trait, known as “vessel dimorphism”, has been identified in studies on water-conducting tissue in autotrophic plants, including a large number of perennial climbing plants and a number of annual vines. Information is lacking on the presence of vessel dimorphism in parasitic plants of the lianescent habit. In this study, we performed a structural analysis of stems in the autotrophic herbaceous vines of Convolvulus arvensis L. and Calystegia sepium (L.) R. Br., as well as in the parasitic vines of Cuscuta monogyna Vahl, Cuscuta planiflora Ten., Cuscuta approximata Bab., and Cuscuta campestris Yunck., of the family of Convolvulaceae Horan. The xylem of C. arvensis and C. sepium contains a few wide conductive elements and many narrow ones. This feature is typical of autotrophic climbing plants. Only narrow tracheary elements are present in the xylem of the parasitic vines of the genus of Cuscuta L. (dodders). The total number of the tracheary elements is an order of magnitude less in the dodders than it is in the autotrophic vines. It is possible that the autotrophic ancestor of dodders lost the characteristic feature of the xylem of climbing plants, known as vessel dimorphism, during its transition to the parasitic lifestyle.

Anatomy and ultrastructure of haustoria in selected West Australian parasitic angiosperms

1990 ◽  
Vol 48 (3) ◽  
pp. 690-691
Author(s):  
John Kuo ◽  
John S. Pate
Keyword(s):  
Parasitic Plants ◽  
The Other ◽  
Nutrient Transfer ◽  
Direct Solution ◽  
Tracheary Elements ◽  
Solute Transfer ◽  
Glycol Methacrylate ◽  
Australian Species ◽  
Anatomy And Ultrastructure ◽  
Solution Transfer

Our understanding of nutrient transfer between host and flowering parasitic plants is usually based mainly on physiological concepts, with little information on haustorial structure related to function. The aim of this paper is to study the haustorial interface and possible pathways of water and solute transfer between a number of host and parasites.Haustorial tissues were fixed in glutaraldehyde and embedded in glycol methacrylate (LM), or fixed in glutaraldehyde then OsO4 and embedded in Spurr’s resin (TEM).Our study shows that lumen to lumen continuity occurs between tracheary elements of a host and four S.W. Australian species of aerial mistletoes (Fig. 1), and some root hemiparasites (Exocarpos spp. and Anthobolus foveolatus) (Fig. 2). On the other hand, haustorial interfaces of the root hemiparasites Olax phyllanthi and Santalum (2 species) are comprised mainly of parenchyma, as opposed to terminating tracheads or vessels, implying that direct solution transfer between partners via vessels or tracheary elements may be limited (Fig. 3).

scholarly journals Search for Resistant Genotypes to Cuscuta campestris Infection in Two Legume Species, Vicia sativa and Vicia ervilia

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 738
Author(s):  
Eva María Córdoba ◽  
Mónica Fernández-Aparicio ◽  
Clara Isabel González-Verdejo ◽  
Carmela López-Grau ◽  
María del Valle Muñoz-Muñoz ◽  
...  
Keyword(s):  
Agricultural Production ◽  
Host Plants ◽  
Resistance Breeding ◽  
Parasitic Plants ◽  
Vicia Sativa ◽  
Common Vetch ◽  
Germplasm Collections ◽  
Bitter Vetch ◽  
Cuscuta Campestris ◽  
Resistant Genotypes

The dodders (Cuscuta spp.) are parasitic plants that feed on the stems of their host plants. Cuscuta campestris is one of the most damaging parasitic plants for the worldwide agricultural production of broad-leaved crops. Its control is limited or non-existent, therefore resistance breeding is the best alternative both economically and environmentally. Common vetch (Vicia sativa) and bitter vetch (Vicia ervilia) are highly susceptible to C. campestris, but no resistant genotypes have been identified. Thus, the aim of this study was to identify in V. sativa and V.ervilia germplasm collections genotypes resistant to C. campestris infection for use in combating this parasitic plant. Three greenhouse screening were conducted to: (1) identify resistant responses in a collection of 154 accessions of bitter vetch and a collection of 135 accessions of common vetch genotypes against infection of C. campestris; (2) confirm the resistant response identified in common vetch accessions; and (3) characterize the effect of C. campestris infection on biomass of V. sativa resistant and susceptible accessions. Most common vetch and bitter vetch genotypes tested were susceptible to C. campestris. However, the V. sativa genotype Vs.1 exhibited high resistance. The resistant phenotype was characterized by a delay in the development of C. campestris posthaustorial growth and a darkening resembling a hypersensitive-like response at the penetration site. The resistant mechanism was effective in limiting the growth of C. campestris as the ratio of parasite/host shoot dry biomass was more significantly reduced than the rest of the accessions. To the best or our knowledge, this is the first identification of Cuscuta resistance in V. sativa genotypes.

Conductance in the wood of selected Carboniferous plants

Paleobiology ◽  
1986 ◽  
Vol 12 (3) ◽  
pp. 302-310 ◽  
Author(s):  
Michael A. Cichan
Keyword(s):  
Wood Anatomy ◽  
Growth Habit ◽  
Secondary Xylem ◽  
Middle Part ◽  
Specific Conductance ◽  
Plant Evolution ◽  
Seed Plant ◽  
Fossil Plants ◽  
Tracheary Elements ◽  
Conducting Tissue

Specific conductance was calculated for secondary xylem in seven Carboniferous stem taxa utilizing an equation derived from the Hagen-Poiseuille relation. Arborescent and lianoid representatives of major pteridophytic (Calamitaceae, Lepidodenraceae, Sphenophyllaceae) and gymnospermous (Cordaitaceae, Medullosaceae) groups were examined. In the calamite Arthropitys communis and the seed plant Cordaites (Cordaixylon sp. and Mesoxylon sp.), conductance corresponded approximately to the low end of the range for both extant conifers and angiosperms. A substantially higher conductance was determined for the wood of Arthropitys deltoides, conforming to the high end of the range for conifers and the low-middle part of the range for angiosperms. The highest conductance values were found in Sphenophyllum plurifoliatum, Medullosa noei, and Paralycopodites brevifolius and corresponded to the middle-high portion of the range for vessel-containing angiosperms. This outcome is particularly significant in light of the fact that tracheary elements in the fossils are imperforate. The results indicate that conductance in secondary xylem of some of the most ancient, woody groups was comparable to that in extant plants and that highly effective conducting tissue developed relatively early in plant evolution. Moreover, it is suggested that the general relationship between wood anatomy, growth habit, and ecology demonstrated for living plants can also be extended back in time to include fossil plants.

scholarly journals Moments of the Critical Values of Families of Elliptic Curves, with Applications

2010 ◽  
Vol 62 (5) ◽  
pp. 1155-1181 ◽  
Author(s):  
Matthew P. Young
Keyword(s):  
Elliptic Curves ◽  
Large Family ◽  
Critical Values ◽  
Central Values ◽  
The Family ◽  
Order Of Magnitude ◽  
Rank 2 ◽  
Family Based ◽  
First Moment ◽  
Positive Rank

AbstractWe make conjectures on the moments of the central values of the family of all elliptic curves and on themoments of the first derivative of the central values of a large family of positive rank curves. In both cases the order of magnitude is the same as that of the moments of the central values of an orthogonal family of L-functions. Notably, we predict that the critical values of all rank 1 elliptic curves is logarithmically larger than the rank 1 curves in the positive rank family.Furthermore, as arithmetical applications, we make a conjecture on the distribution of ap's amongst all rank 2 elliptic curves and show how the Riemann hypothesis can be deduced from sufficient knowledge of the first moment of the positive rank family (based on an idea of Iwaniec).

scholarly journals Extensive plastome reduction and loss of photosynthesis genes in Diphelypaea coccinea, a holoparasitic plant of the family Orobanchaceae

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7830 ◽  
Author(s):  
Eugeny V. Gruzdev ◽  
Vitaly V. Kadnikov ◽  
Alexey V. Beletsky ◽  
Andrey V. Mardanov ◽  
Nikolai V. Ravin
Keyword(s):  
Genome Evolution ◽  
Plastid Genome ◽  
Housekeeping Genes ◽  
Parasitic Plants ◽  
Rrna Genes ◽  
Phylogenetic Position ◽  
Trna Genes ◽  
Protein Coding ◽  
The Family ◽  
Plastid Genome Evolution

Background Parasitic plants have the ability to obtain nutrients from their hosts and are less dependent on their own photosynthesis or completely lose this capacity. The reduction in plastid genome size and gene content in parasitic plants predominantly results from loss of photosynthetic genes. Plants from the family Orobanchaceae are used as models for studying plastid genome evolution in the transition from an autotrophic to parasitic lifestyle. Diphelypaea is a poorly studied genus of the Orobanchaceae, comprising two species of non-photosynthetic root holoparasites. In this study, we sequenced the plastid genome of Diphelypaea coccinea and compared it with other Orobanchaceae, to elucidate patterns of plastid genome evolution. In addition, we used plastid genome data to define the phylogenetic position of Diphelypaea spp. Methods The complete nucleotide sequence of the plastid genome of D. coccinea was obtained from total plant DNA, using pyrosequencing technology. Results The D. coccinea plastome is only 66,616 bp in length, and is highly rearranged; however, it retains a quadripartite structure. It contains only four rRNA genes, 25 tRNA genes and 25 protein-coding genes, being one of the most highly reduced plastomes among the parasitic Orobanchaceae. All genes related to photosynthesis, including the ATP synthase genes, had been lost, whereas most housekeeping genes remain intact. The plastome contains two divergent, but probably intact clpP genes. Intron loss had occurred in some protein-coding and tRNA genes. Phylogenetic analysis yielded a fully resolved tree for the Orobanchaceae, with Diphelypaea being a sister group to Orobanche sect. Orobanche.

scholarly journals Hyalesthes obsoletus is an active vector of Wood blackening in the Republic of Moldova

2021 ◽  
Vol 34 ◽  
pp. 04020
Author(s):  
Evgeniy Haustov ◽  
Victor Bondarciuc
Keyword(s):  
Climatic Conditions ◽  
Xanthium Strumarium ◽  
Convolvulus Arvensis ◽  
Bois Noir ◽  
Republic Of Moldova ◽  
Sonchus Oleraceus ◽  
Field Bindweed ◽  
Calystegia Sepium ◽  
The Republic ◽  
Hyalesthes Obsoletus

Hyalesthes obsoletus (Signoret) is an important vector of Wood Blackening in the Republic of Moldova. To identify the causes of the epidemiology of this disease in vineyards, the period of flight and the preference of the host plant H. obsoletus in the field were studied. Monitoring of vineyards showed that this species was found on the Field Bindweed (Convolvulus arvensis L.), and during the period of mass flight, the leafhopper was observed on Xanthium strumarium and Gorets bindweed (Fallopia convolvulus L.). The captured leafhoppers were diagnosed with the presence of Bois Noir stolbur phytoplasm (STOL). The adults of H. obsoletus were also caught from other herbaceous plants: Povoy fence (Calystegia sepium L.), Garden quinoa (Ariplex hortensis L.), Sow thistle (Sonchus oleraceus L.), Medicinal dandelion (Taraxacum officinale L.), as well as c Stinging nettle (Urtica dioica L.). Changes in climatic conditions in the region, causing premature drying of the grass cover, forces cicadas - vectors to switch to actively growing plants during this period, including grapes, which contributes to the widespread of the disease.

Fusicladium convolvularum. [Descriptions of Fungi and Bacteria].

2002 ◽  
Author(s):  
K. Schubert
Keyword(s):  
Czech Republic ◽  
New Zealand ◽  
Great Britain ◽  
Geographical Distribution ◽  
Leaf Spot ◽  
Convolvulus Arvensis ◽  
Airborne Conidia ◽  
Calystegia Sepium

Abstract A description is provided for Fusicladium convolvularum. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Leaf spot. HOSTS: Species of Calystegia and Convolvulus (Convolvulaceae), including Calystegia sepium, C. soldanella and Convolvulus arvensis. GEOGRAPHICAL DISTRIBUTION: AUSTRALASIA: New Zealand. EUROPE: Czech Republic, Great Britain. TRANSMISSION: Presumably by airborne conidia.

Wood Anatomy of Trees and Shrubs from China. I. Oleaceae

IAWA Journal ◽  
1986 ◽  
Vol 7 (3) ◽  
pp. 195-220 ◽  
Author(s):  
Pieter Baas ◽  
Zhang Xinying
Keyword(s):  
Vessel Wall ◽  
Wood Anatomy ◽  
Wood Structure ◽  
Tracheary Elements ◽  
The Family ◽  
Trees And Shrubs

The wood anatomy of 34 species belonging to nine genera of Oleaceae, native or commonly cultivated in China, is described in detail, and a key to the identification of the genera is given. The diversity in wood structure supports the grouping of genera as based on a worldwide wood anatomical survey of the family by Esser and Van der Westen (1983) and Esser et al. (in preparation). Characters to separate these groups are type of imperforate tracheary elements (libriform fibres or fibre-tracheids), vessel distribution and grouping (mainly solitary or mainly in multiples; in an oblique to dendritic pattern or not), presence or absence of vascular tracheids, presence or absence of parenchyma bands (mostly marginal), and vessel wall sculpturing and intervessel pit size.

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