Production of genetically uniform plants from nodal explants of <Emphasis Type="Italic">Swertia chirata</Emphasis> Buch.-Ham. ex Wall.—an endangered medicinal herb

Swertia chirata is an endangered Gentian species used as herbal medicine for various health ailments including liver disorders, malaria, and diabetes. The depletion of S. chirata from the wild for such applications is a concern. Slow rates of propagation because of poor seed germination and low seed viability are presently limiting factors for its large-scale commercial cultivation. For commercial plantation and conservation of existing germplasm, in vitro multiplication is an attractive solution. The present investigation has achieved production of genetically uniform plants from the nodal explants. Shoot regeneration was obtained in shoot-inducing medium containing half-strength Murashige and Skoog’s basal medium supplemented with 0.44 μM 6-benzylaminopurine and 4.65 μM 6-furfurylaminopurine. The highest number of shoots, at 18 per explant, regenerated when media was further fortified with 10 mM KNO₃ and 75 mg l⁻¹ of casein hydrolysate. Tissue culture regenerated plantlets were successfully transferred to the field and produced viable seeds. Studies of chromosome number and a comparative analysis of the DNA fingerprinting profiles indicate genetic stability of the regenerated plants.     

Conservation strategies for threatened medicinal plant – Barleria prionitis L. – using in vitro and ex vitro propagation techniques

Over-utilisation and continuous depletion of medicinal plants have affected their supply and loss of genetic diversity. Hence the current study is based on conservation strategies for threatened medicinal plants with special reference to Barleria prionitis L. using in vitro and ex vitro propagation techniques. We have developed here a protocol for plant regeneration of Barleria prionitis L. We have also developed an efficient system of vegetative propagation of Barleria prionitis L. through stem cuttings using revive rooting hormones. These studies can be useful for conservation strategies of this important medicinal plant.     

In vitro propagation of Gentiana kurroo — an indigenous threatened plant of medicinal importance

Shoot multiplication of Gentiana kurroo Royle, a threatened medicinal plant species, was achieved in vitro using shoot tips and nodal segments as explants. Fifteen-fold shoot multiplication occurred every 6 weeks on Murashige and Skoog's medium (MS) containing 8.9 M benzyladenine and 1.1 M 1-naphthaleneacetic acid. Rooting was accomplished successfully in excised shoots grown on MS basal medium containing 6% sucrose.Abbreviations BA 6-benzyladenine - IAA Indole-3-acetic acid - IBA Indole-3-butyric acid - MS Murashige and Skoog's medium - NAA 1-naphthaleneacetic acid     

In vitro propagation and conservation of Satureja avromanica Maroofi—an indigenous threatened medicinal plant of Iran

Physiology and Molecular Biology of Plants - An efficient and rapid in vitro propagation system for Satureja avromanica, a rare and endangered folk medicinal plant of Iran was developed through the...     

Sonneratia apetala Buch.Ham in the mangrove ecosystems of China: An invasive species or restoration species?

By the end of 1990s when China initiated a 10-year mangrove reforestation project, the mangrove forest area had decreased from 250,000 to 15,000 ha. Over 80% of current Chinese mangroves are degraded secondary forests or plantations. As an initial restoration and reforestation effort, Sonneratia apetala, a native of India, Bengal and Sri Lanka, was introduced in 1985 to Dong Zhaigang Mangrove Nature Reserve in Hainan Island from Bengal. It has then been introduced into other places since 1991. However, the further use of the species is becoming increasingly controversial as there are emerging signs that it may become invasive in certain locations. A comprehensive evaluation of the species’ condition in China regarding benefits and risks is critically needed. Here, we map the introduction and dispersal routes and monitor the growth of S. apetala in China from 1985 to 2006. S. apetala grows fast and performs well in the introduced 2300 ha muddy beaches area. It greatly improves the soil fertility and shows a suite of suitable characteristics as a pioneer restoration species. Currently, no natural invasion of S. apetala has been observed in the northern mangrove area. However, invasion into natural forests does occur in southerly locations such as Shenzhen, Zhanjiang and Dong Zhaigang. In these locations, S. apetala exhibits invasive characteristics such as overgrowth and high spreading ability that evidently affects local mangrove ecosystem structure and function. While the species clearly offers some benefits at some locations where it cannot naturally invade, it appears harmful to other native mangrove species, posing a major practical problem to both ecologists and land managers. This situation will be similar to previously imported non-native and invasive intertidal wetland species, Spartina alterniflora (smooth cordgrass), with similar results and problems.     

Hymenopyramis Wall. ex Griff.—A New Recorded Genus of Verbenaceae from China

The present paper reports the first record of the genus Hymenopyramis in China. H. cana is a new record on Hainan Island of Guangdong Province. It grows in deciduous monsoon forests or shrubby savanna (western Hainan) at 50 to 150 m alt.     

Micropropagation of <Emphasis Type="Italic">Terminalia bellirica</Emphasis> Roxb.—A sericulture and medicinal plant

Summary A protocol for micropropagation of plants via axillary bud proliferation from nodal explants of Terminalia bellirica Roxb. seedlings has been established. Explants were cultured on Murashige and Skoog medium with different concentrations of 6-benzyladenine (BA; 4.4, 8.9, 13.3, 17.8, or 22.2 μM) or kinetin (Kn; 4.6, 9.3. 14.0, 18.6, or 23.2 μM). Within the range evaluated, the medium containing 13.3 μM BA showed the highest shoot length (1.9=0.2 cm) in the primary culture. When separated and transferred to fresh subculture medium with lower levels of BA (2.2. 4.4, 6.6, or 8.9 μM) or Kn (2.3, 4.6, 6.9, or 9.3 μM), the nodal segments from individual regenerants (obtained initially from seedling nodes) showed efficient shoot induction at 4.4 μM BA. Rooting of the shoots was achieved under in vitro conditions on two media tested, i.e., modified Gamborg's (B₅) medium or Woody Plant Medium, both supplemented with 4.9 μM indole-3-butyric acid. Regenerated plants were established in the greenhouse.     

Micropropagation of <Emphasis Type="Italic">Leptadenia reticulata</Emphasis>—A medicinal plant

Summary Leptadenia reticulata (Retz.) Wight. & Arn., an important herbal medicinal plant, belongs to the family Asclepiadaceae. This plant has been known for its medicinal uses since 4500 BC. Presently this is an endangered species. There is a need for applying non-conventional methods of propagation for conservation and sustainable utilization of biodiversity of Leptadenia reticulata. We developed a micropropagation method for mass multiplication of L. reticulata. Explants harvested from greenhouse-maintained and field-grown plants were used to establish cultures of L. reticulata. The nodal shoot segments were surface-sterilized and cultured on Murashige and Skoog (MS) medium along with additives (25 mg l⁻¹ each of adenine sulfate, arginine, and citric acid, and 50 mg l⁻¹ ascorbic acid) containing 0.6 μM indole-3-acetic acid (IAA) and 9 μM N⁶-benzyladenine (BA). Three to four shoots differentiated from each node within 25–30 d at 26±2°C and 36 μmol m⁻² s⁻¹ spectral flux photon (SFP) for 12 hd⁻¹. Shoots were further multiplied by (1) repeated transfer of mother explant on fresh medium containing 0.6 μM IAA and 2.2 μM BA, and (2) subculture of in vitro-differentiated shoots on MS medium with 6.6 μM BA and 0.6 μM IAA. After three or four subcultures, the basal clump with shoot bases was divided into three or four subclumps and multiplied on the fresh medium. From each clump 15–20 shoots regenerated within 25 d. Ninety percent of the in vitro-produced shoots rooted ex vitro if these were pulse-treated with 123 μM each of indole-3-butyric acid and β-naphthoxyacefic acid. The plantlets were transferred to bottles containing sterile ‘soilrite’ (soilless compost and soil conditioner) moistened with half-strength MS macrosalts. Ninety-five percent of the plantlets were hardened in the bottles within 15 d. The hardened plants were then transferred to black polybags in the nursery. Field transferred plants are growing normally and have flowered. The protocol developed is reproducible. From a single nodal segment about 1700 hardened plants could be regenerated within 174 d.     

Sapelenins G–J,acyclic triterpenoids with strong anti-inflammatory activities from the bark of the Cameroonian medicinal plant Entandrophragma cylindricum

Four acyclic triterpene derivatives named sapelenins G–J (1–4), along with eight known compounds, sapelenins A–D, ekeberin D2 (5), (+)-catechin and epicatechin, and anderolide G, were isolated from the stem bark of the Cameroonian medicinal plant, Entandrophragma cylindricum Sprague, on the basis of bioassay-guided fractionation. Their structures were determined by means of high-resolution mass spectrometry and NMR spectroscopic data, as well as by comparison with the literature values of their analogs. The absolute configurations of the compounds (1–4) were assigned by the modified Mosher’s method in conjunction with NOESY experiments and chemical modifications. The anti-inflammatory activities of the sapelenins were evaluated by assessing their ability to suppress or inhibit the secretion of cytokine interleukin-17 (IL-17) by human peripheral blood mononuclear cells (PBMC) stimulated with phytohemagglutinin (PHA). The cytotoxicity of these compounds on PMBCs was further assessed for correctly interpreting their anti-inflammatory responses. The tested compounds demonstrated moderate to significant anti-inflammatory activities by suppressing the secretion of IL-17 by PHA-stimulated human PBMCs. One of them, sapelenin G (1), showed high potency in suppressing the secretion of IL-17 by PBMCs comparable to reference cyclosporine A, without causing any cytotoxic effects (negligible), and deserves further considerations towards developing an effective anti-inflammatory drug.     

Comparing the conservatism of ecological interactions in plant–pollinator and plant–herbivore networks

Conservatism in species interaction, meaning that related species tend to interact with similar partners, is an important feature of ecological interactions. Studies at community scale highlight variations in conservatism strength depending on the characteristics of the ecological interaction studied. However, the heterogeneity of datasets and methods used prevent to compare results between mutualistic and antagonistic networks. Here we perform such a comparison by taking plant–insect communities as a study case, with data on plant–herbivore and plant–pollinator networks. Our analysis reveals that plants acting as resources for herbivores exhibit the strongest conservatism in species interaction among the four interacting groups. Conservatism levels are similar for insect pollinators, insect herbivores and plants as interacting partners of pollinators, although insect pollinators tend to have a slightly higher conservatism than the two others. Our results thus clearly support the current view that within antagonistic networks, conservatism is stronger for species as resources than for species as consumer. Although the pattern tends to be opposite for plant–pollinator networks, our results suggest that asymmetry in conservatism is much less pronounced between the pollinators and the plant they interact with. We discuss these differences in conservatism strength in relation with the processes structuring plant–insect communities.     

Propagation through alginate encapsulation of axillary buds of Cannabis sativa L. — an important medicinal plant

Cannabis sativa L. (Cannabaceae) is an important medicinal plant well known for its pharmacologic and therapeutic potency. Because of allogamous nature of this species, it is difficult to maintain its potency and efficacy if grown from the seeds. Therefore, chemical profile-based screening, selection of high yielding elite clones and their propagation using biotechnological tools is the most suitable way to maintain their genetic lines. In this regard, we report a simple and efficient method for the in vitro propagation of a screened and selected high yielding drug type variety of Cannabis sativa, MX-1 using synthetic seed technology. Axillary buds of Cannabis sativa isolated from aseptic multiple shoot cultures were successfully encapsulated in calcium alginate beads. The best gel complexation was achieved using 5 % sodium alginate with 50 mM CaCl₂.2H₂O. Regrowth and conversion after encapsulation was evaluated both under in vitro and in vivo conditions on different planting substrates. The addition of antimicrobial substance — Plant Preservative Mixture (PPM) had a positive effect on overall plantlet development. Encapsulated explants exhibited the best regrowth and conversion frequency on Murashige and Skoog medium supplemented with thidiazuron (TDZ 0.5 μM) and PPM (0.075 %) under in vitro conditions. Under in vivo conditions, 100 % conversion of encapsulated explants was obtained on 1:1 potting mix- fertilome with coco natural growth medium, moistened with full strength MS medium without TDZ, supplemented with 3 % sucrose and 0.5 % PPM. Plantlets regenerated from the encapsulated explants were hardened off and successfully transferred to the soil. These plants are selected to be used in mass cultivation for the production of biomass as a starting material for the isolation of THC as a bulk active pharmaceutical.Key words: Encapsulation, Nodal explants, Plant growth regulators, Plant regeneration, Synthetic seeds     

Could taxonomic misnaming threaten the ex situ conservation and the usage of plant genetic resources?

Ex situ conservation of plant germplasm, especially seed banking, is a favourable and widely used method for the conservation of plant genetic resources (PGR). The long-term conservation of these resources is fundamental for food security and plant breeding in order to stem the losses in agrobiodiversity and to meet the global challenges that agriculture is facing. The conservation and accessibility of PGR relies on their correct taxonomic labelling and on the building of a searchable database that links ex situ collections together. In the current study, we analysed the impact of taxonomic misnaming in the two major PGR databases (Genesys PGR, EURISCO), listing accessions conserved worldwide. The aim was to understand if taxonomic misnaming issues prevent PGR conservation. We chose as a case-study seed collections of accessions of the genus Citrullus (watermelon genepool), the taxonomy and nomenclature of which have been largely revised in recent times. We observed that taxonomic misnaming greatly limits PGR conservation with only 3% of the accessions listed in the databases correctly named; moreover, 28% were affected by taxonomic errors that prevent the establishment of the accessions’ taxonomic identity, with consequences on their conservation and exploitation. The existence of the problem was also confirmed by the experimental propagation of three misnamed accessions. We suggest herein a series of actions that, put in place, could solve the extant misnaming issues in the databases and prevent their reoccurrence, allowing the correct conservation and the usability by the stakeholders of all the accessions.     

The germacranolide sesquiterpene lactone neurolenin B of the medicinal plant Neurolaena lobata (L.) R.Br. ex Cass inhibits NPM/ALK-driven cell expansion and NF-κB-driven tumour intravasation

BackgroundThe t(2;5)(p23;q35) chromosomal translocation results in the expression of the fusion protein NPM/ALK that when expressed in T-lymphocytes gives rise to anaplastic large cell lymphomas (ALCL). In search of new therapy options the dichloromethane extract of the ethnomedicinal plant Neurolaena lobata (L.) R.Br. ex Cass was shown to inhibit NPM/ALK expression.PurposeTherefore, we analysed whether the active principles that were recently isolated and found to inhibit inflammatory responses specifically inhibit growth of NPM/ALK+ ALCL, leukaemia and breast cancer cells, but not of normal cells, and the intravasation through the lymphendothelial barrier.MethodsALCL, leukaemia and breast cancer cells, and normal peripheral blood mononuclear cells (PBMCs) were treated with isolated sesquiterpene lactones and analysed for cell cycle progression, proliferation, mitochondrial activity, apoptosis, protein and mRNA expression, NF-κB and cytochrome P450 activity, 12(S)-HETE production and lymphendothelial intravasation.ResultsIn vitro treatment of ALCL by neurolenin B suppressed NPM/ALK, JunB and PDGF-Rβ expression, inhibited the growth of ALCL cells late in M phase, and induced apoptosis via caspase 3 without compromising mitochondrial activity (as a measure of general exogenic toxicity). Moreover, neurolenin B attenuated tumour spheroid intravasation probably through inhibition of NF-κB and CYP1A1.ConclusionNeurolenin B specifically decreased pro-carcinogenic NPM/ALK expression in ALK+ ALCL cells and, via the inhibition of NF-kB signalling, attenuated tumour intra/extravasation into the lymphatics. Hence, neurolenin B may open new options to treat ALCL and to manage early metastatic processes to which no other therapies exist.     

Tracing the evolutionary routes of plant–microbiota interactions

1. Download : Download high-res image (190KB)
2. Download : Download full-size image

     

Floral Morphogenesis of Anemone rivularis Buch.-Ham. ex DC. var.flore-minore Maxim. （Ranunculaceae） with Special Emphasis on Androecium Developmental Sequence

The floral morphogenesis and androecium developmental sequence of Anemone rivularis Buch.-Ham. ex DC. var.flore-rninore Maxim. were observed under a scanning electron microscope (SEM) and by means of histological methods in order to expand our knowledge of the morphogenesis and development of the floral organs of the Ranunculaceae. The initiation of the floral elements is a centripetal spiral and the direction of the spiral is clockwise or anti-clockwise. However, the development of the androecium is highly unusual: in a longitudinal series of four stamens, the second stamen develops first from the inner to outer, then the third one, the fourth one and the first one in turn. The microsporogenesisand ant her maturation follows the same developmental sequence. The tepals are different from the bracts and the stamens in both shape and size in the early developmental stage, but there is no difference between the stamens and carpels in the early developmental stage. Therefore, we established a spatio-temporal process of the floral morphogenesis ofA. rivularis var.flore-rninore and offer another meaning of the floral diversity patterns attributed to the level of the genus.     

Improved in vitro clonal propagation of Rauwolfia serpentina L. Benth – An endangered medicinal plant

In this protocol, 96% of bud proliferation was observed after 14 days of inoculation. Highest rate of shoot multiplication (13.3 shoots per explant) with an average shoot length of 8.2 cm was observed in Murashige and Skoog (MS) medium+2 mg/l 6-benzylaminopurine+0.25 mg/l 1-naphthaleneacetic acid+3% sucrose. Half MS (1/2 MS)+0.5 mg/l indol-3-butyric acid proved best with 73.3% rooting. The rooted shoots showed 90% survival. Genetic uniformity of the micropropagated plants with their donor plants was confirmed through random amplified polymorphic DNA molecular technique.     

Effect of livestock grazing in the partitions of a semiarid plant–plant spatial signed network

In recent times, network theory has become a useful tool to study the structure of the interactions in ecological communities. However, typically, these approaches focus on a particular kind of interaction while neglecting other possible interactions present in the ecosystem. Here, we present an ecological network for plant communities that consider simultaneously positive and negative interactions, which were derived from the spatial association and segregation between plant species. We employed this network to study the structure and the association strategies in a semiarid plant community of Cabo de Gata-Níjar Natural Park, SE Spain, and how they changed in 4 sites that differed in stocking rate. Association strategies were obtained from the partitions of the network, built based on a relaxed structural balance criterion. We found that grazing simplified the structure of the plant community. With increasing stocking rate species with no significant associations became dominant and the number of partitions decreased in the plant community. Independently of stocking rate, many species presented an associative strategy in the plant community because they benefit from the association to certain ‘nurse’ plants. These ‘nurses’ together with species that developed a segregating strategy, intervened in most of the interactions in the community. Ecological networks that combine links with different signs provide a new insight to analyze the structure of natural communities and identify the species which play a central role in them.