In vitro multiplication, micromorphological studies and ex vitro rooting of Hybanthus enneaspermus (L.) F. Muell. – a rare medicinal plant

Hybanthus enneaspermus is a rare medicinal plant. We defined a protocol for micropropagation, exvitro rooting of cloned shoots and their acclimatization. Surface-sterilized nodal segments were cultured on Murashige and Skoog (MS) medium with different concentrations of 6-benzylaminopurine (BAP) and kinetin (Kin). Medium supplemented with 1.5 mg L–1 BAP was found optimum for shoot induction from the explants and 6.4±0.69 shoots were regenerated from each node with 97% response. Shoots were further proliferated maximally (228±10.3 shoots per culture bottle with 7.5±0.43 cm length) on MS medium augmented with 1.0 mg L–1 each of BAP and Kin within 4–5 weeks. The shoots were rooted in vitro on half strength MS medium containing 2.0 mg L–1 indole-3 butyric acid (IBA). The cloned shoots were pulse-treated with 300 mg L–1 of IBA and cultured on soilrite® in a greenhouse. About 96% of the IBA-pulsed shoots rooted ex vitro in soilrite®, each shoot producing 12.5±0.54 roots with 5.1±0.62 cm length. The ex vitro rooted plantlets showed a better rate of survival (92%) in a field study than in vitro rooted plantlets (86%). A comparative foliar micromorphological study of H. enneaspermus was conducted to understand the micromorphological changes during plant developmental processes from in vitro to in vivo conditions in terms of variations in stomata, vein structures and spacing, and trichomes. This is the first report on ex vitro rooting in H. enneaspermus and the protocol can be exploited for conservation and large-scale propagation of this rare and medicinally important plant

Biogenesis of silver nanoparticles using leaf extract of Turnera ulmifolia Linn. and screening of their antimicrobial activity

Development of nontoxic and clean techniques for the synthesis of silver nanoparticles (Ag NPs) has attracted increasing attention in recent years. The biological synthesis of silver nanoparticles using Turnera ulmifolia plant leaf extract was studied in present investigation. The synthesized nanoparticles were confirmed by color changes from pale green to reddish brown and characterized by UV-Visible spectrophotometer. A peak between 415 nm to 425 nm was obtained on spectrometer characterized the biosynthesis of silver nanoparticles. The synthesized nanoparticles also showed antibacterial activity against four disease causing microorganisms

Comparative foliar micromorphological studies of in vitro and field transferred plants of Morinda citrifolia

Micromorphological studies revealed the developmental changes in micropropagated plants of Morinda citrifolia L. from in vitro conditions to field environment. The lower relative humidity, higher light intensity and septic stressful conditions in the field environment could make gradual changes in the micropropagated plants so as to adapt the external environment. Arrested stomatal development, single guard cells and indistinct subsidiaries were observed in vitro with highest stomatal density (52.0±0.11) obtained in the ambient in vitro environment. The development of tissues, epidermal ornamentation, efficient stomatal functionality and vein-islets numbers (12.0±0.0) during in vivo transfer may help in acclimation of micropropagated plants under field conditions. Raphides were observed in the in vitro propagated as well as in vivo transferred plantlets. The gradual acclimatisation and ex vitro rooting technique increased the survival rate of plantlets in the field. The micromorphological changes resulting from in vitro to field environments are important to understand the development of tissues and adaptation of micropropagated plants, which could help in improvement in survivability during field trials

Zinc Oxide nanoparticles synthesis by use of aqueous extracts of Muntingia calabura L.

Biological synthesis of metal nanoparticles gained worldwide interest due to their rapid, non-toxic, economical, single-step technique and eco-friendly alternative. Green-chemical approach of production of Zinc Oxide (ZnO) nanoparticles (NPs) has been exploited in the field of medicine, food packaging, nano-optical and electrical devices. Muntingia calabura is a multipotent medicinal plant with astounded biological activities and phytoconstituents. The nanoparticles obtained using aqueous extracts of various parts of M. calabura were characterized with UV-VIS spectroscopy to obtain information concerning the optical properties of synthesized ZnO nanoparticles. The proposed green and economical method could be used for large scale production of nanostructures because of its advantages over other physical and chemical methods

Biological Approach for the Synthesis and Characterization of Zinc Oxide Nanopaticles from Croton bonplandianum Baill. Extracts

The biogenesis of nanoparticles recently gained more attention. Here, we report the biogenesis of zinc oxide (ZnO) nanoparticles using aqueous extracts of the leaves, stem, root, flowers and fruits of Croton bonplandianum Baill. at room temperature. Croton bonplandianum is an important medicinal plant used to cure many pathological conditions in the traditional systems of Indian medicines due to the presence of important and specific bioactive compounds in the plant parts of this plant. Aqueous solution of Zinc Nitrate hexahydrate [Zn(NO3)2·6H2O] was used as a precursor and the various plant extracts played as reducing agents. The formation of ZnO nanoparticles was monitored by UV-Visible spectrophotometric analysis. The leaf extract showed strong absorbance peak at 302 nm, stem and fruit at 293 nm, root at 290 nm and flowers at 305 nm

Somatic embryogenesis and in vitro flowering in Hybanthus enneaspermus (L.) F. Muell. – A rare multipotent herb

Objective: Present study reports the various factors affecting somatic embryogenesis and in vitro flowering in Hybanthus enneaspermus (L.) F. Muell. Methods: The effect of the salts strength of Murashige and Skoog's (MS) medium, concentration of sucrose and plant growth regulators were analyzed for the induction of direct somatic embryogenesis using nodal segments as explants. Results: High frequency of somatic embryogenesis was reported on full strength MS medium (with 3% sucrose) and additives supplemented with 0.5 mg/L 6-benzylaminopurine (BAP) and 0.25 mg/L indole-3-acetic acid (IAA). Maximum somatic embryos (207.0 ± 4.2) were germinated on 1/2 strength MS medium augmented with 0.5 mg/L BAP. Microscopic studies revealed the typical developmental patterns in somatic embryogenesis from globular to heart-shaped and followed by bipolar torpedo-shaped somatic embryos from nodal explants. The plantlets raised from the somatic embryos resulted in flowering on full strength MS medium augmented with 1.0 mg/L each of BAP and Kinetin (Kin) + 0.5 mg/L IAA at 50 μmol/(m2·s) SFPD for 13 h/d photoperiod. About 92% plantlets were successfully acclimatized in the greenhouse. Field transferred plants exhibit normal flowering and fruit setting. Conclusions: The study could be exploited for large scale propagation of true to type plants as conservation strategies of this rare and endemic medicinal plant

Impact of Auxins on Vegetative Propagation through Stem Cuttings of Couroupita guianensis Aubl.: A Conservation Approach

The present study explores the potential of exogenous auxins in the development of adventitious shoots and roots from shoot cuttings of Couroupita guianensis (Nagalingam), a threatened tree. Experiments were conducted to assess the effect of various concentrations of auxins on shoot and root morphological traits of stem cuttings in the greenhouse. Amongst the auxins tested, significant effects on number of shoot buds’ induction and their growth were observed with α-Naphthalene Acetic Acid (NAA) treated nodal cuttings. Cent percentage of the stem cuttings of C. guianensis were rooted and shoots were induced when pretreated with 400 mg L−1 NAA for 5 min. Maximum 79% of stem cuttings responded to pretreatment of 300 mg L−1 indole-3-butyric acid (IBA) for 5 min, and 75% of stem cuttings induced shoots with 400 mg L−1 indole-3-acetic acid (IAA). Presence of at least 5 nodes on stem cuttings was found to be prerequisite for root and shoot induction. About 92% of plants were survived under natural soil conditions raised from the stem cuttings. This is the first report of vegetative propagation of C. guianensis through stem cuttings which could be used for conservation strategy and sustainable utilization of this threatened medicinal tree