Iyyakkannu Sivanesan

Micropropagation of Cotoneaster wilsonii Nakai—a rare endemic ornamental plant

A simple and efficient micropropagation system was developed for Cotoneaster wilsonii through node and shoot tip explants obtained from mature field-grown plants. Of the two explants, node explants were found to be the most effective for axillary shoot proliferation. The highest frequency of shoot induction was achieved when nodal explants were incubated on Murashige and Skoog (MS) medium supplemented with 0.5xa0mg L−1 thidiazuron (TDZ) and 0.1xa0mg L−1 α- naphthaleneacetic acid (NAA) with an average of 34 shoots per explant. The microshoots were separated from the multiple shoots and subcultured on MS medium supplemented with 3% (w/v) sucrose and 0.8% (w/v) agar for further shoot growth. Maximum rooting was obtained on half-strength MS medium supplemented with 0.5xa0mg L−1 indole-3-butyric acid (IBA). The in vitro-grown plantlets were successfully acclimatized in a glasshouse with 98% of survival. High concentrations of TDZ (1.5–2.0xa0mg L−1) and repeated subcultures resulted hyperhydric shoots. Supplementation of the culture medium with silicon significantly reduced the induction of hyperhydric shoots. Increasing silicon concentration significantly decreased malondialdehyde content of the regenerated shoots. Data indicate that addition of silicon to the culture medium can effectively control hyperhydricity.

Influence of silicon supplementation on the growth and tolerance to high temperature in Salvia splendens

In this study, effects of silicon (Si) on the growth and activities of major antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX), and protein profile under high temperature stress were investigated. Salvia splendens ‘Vista Red’ and ‘Sizzler Red’ were grown in a glasshouse and potassium silicate (0 or 100 mg·L−1) was supplemented hydroponically. Overall important growth parameters, chlorophyll content, and biomass were significantly increased by Si application. In both cultivars, more Si deposition occurred in the root, followed by leaf and flower. In both normal and high temperature conditions, supplemented Si increased the activity of SOD, APX, and GPX, while it decreased the CAT activity. In the SDS-PAGE protein profile, three bands responding differentially to the Si treatment were observed. Especially in ‘Vista Red’ treated with Si, a protein band, approximately 46 kDa, was expressed strongly under the temperature stress. Results of this experiment showed that Si not only promoted the growth of salvia, but also played a vital role against temperature stress.

Somatic embryogenesis and plant regeneration from leaf and petiole explants of Campanula punctata Lam. var. rubriflora Makino

A simple and efficient protocol was developed for somatic embryogenesis from leaf and petiole explants of Campanula punctata Lam. var. rubriflora Makino. Somatic embryos (SE) were obtained with greater frequency from petiole explants than from leaf explants when cultured on Murashige and Skoog (MS) medium supplemented with 2.0xa0mgxa0L−1 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.0xa0mgxa0L−1 6-benzyladenine (BA). On this medium, a mean number of 19.5 and 31.2 SE were developed per leaf and petiole explants, respectively. Embryos were induced both light and dark conditions but culturing the explants 2xa0weeks in the dark followed by 3xa0weeks under light resulted in high frequency of embryo formation. Globular embryos germinated best on MS medium supplemented with 0.3% (w/v) activated charcoal (AC) and 1.0xa0mgxa0L−1 GA3. The germinated plantlets grew further on MS medium containing 0.3% AC. Plantlets were successfully acclimatized in the greenhouse with 94% survival rate. This is the first report on induction of somatic embryogenesis in this genus and also has implications for genetic transformation, and mass clonal propagation.

Silicon Supply through the Subirrigation System Affects Growth of Three Chrysanthemum Cultivars

The effect of silicon (Si) treatment on the growth of three chrysanthemum cultivars grown in a soilless substrate was evaluated. Rooted terminal cuttings of Dendranthema grandiflorum ‘Gaya Pink’, ‘Lemmon Tree’, and ‘White Angel’ were transplanted into pots containing a coir-based substrate. A nutrient solution containing 0, 50, or 100 mg·L−1 Si from potassium silicate was supplied once a day through a subirrigation system. Application of Si significantly increased the plant height, stem diameter, number of branches, and chlorophyll content, as compared to the control. Addition of Si at 50 and 100 mg·L−1 into the nutrient solution significantly enhanced number and size of flowers, respectively. When plants were treated with Si necrotic lesions appeared in the older leaves at the beginning of the flowering stage. Concentrations of phosphorus (P), sulfur (S), calcium (Ca), magnesium (Mg), and zinc (Zn) in the leaves increased, while the concentrations of potassium (K), boron (B), copper (Cu), iron (Fe), and manganese (Mn) decreased with the increasing Si concentration in the nutrient solution. Among the cultivars, ‘Lemmon Tree’ contained the greatest Si concentration (1364 μg·g−1) followed by ‘Gaya Pink’ (1158 μg·g−1) and ‘White Angel’ (586 μg·g−1).

Silicon promotes shoot proliferation and shoot growth of Salvia splendens under salt stress in vitro

Silicon (Si) is known to have beneficial effects on plants especially in monocots such as rice, wheat, and sugarcane. The objective of this study was to examine the effect of Si against NaCl on axillary shoot proliferation and shoot growth of in vitro of Salvia splendens ‘Hot Jazz’, one of the important floricultural plants. In vitro study was chosen because in such controlled environment the mechanism of Si alleviation can be clearly studied without any external hindrance. Nodal explants have been cultured on the MS medium supplemented with 3.0 mg·L−1 6-benzylaminopurine (BAP) and 0.5 mg·L−1 indole-3-acetic acid (IAA) with or without 50 or 100 mM NaCl as the salt stress source and 50 or 100 mg·L−1 K2SiO3 as the Si source. Salt stress exhibited strong retardation on growth parameters such as number and length of shoots and internodes, chlorophyll content, and the fresh and dry weights of shoots. At 50 mM NaCl both 50 and 100 mg·L−1 K2SiO3 helped to overcome the salt effect and maximized the plant growth. Though the Si gave tolerance and increased growth even in the 100 mM NaCl treatment, it was not as much effective as in the 50 mM NaCl treatment. In conclusion, these results put forward an experimental evidence for further studies of Si on salinity stress in ornamental plants.

Structural, vibrational (FT-IR and FT-Raman) and UV-Vis spectral analysis of 1-phenyl-3-(1,2,3-thiadiazol-5-yl)urea by DFT method.

The Fourier Transform Infrared (FT-IR) and FT-Raman spectra of 1-phenyl-3-(1,2,3-thiadiazol-5-yl)urea (TDZ) have been recorded and analyzed. The molecular structure and vibrational spectra (harmonic and anharmonic) of TDZ were calculated by the Density Functional Theory (DFT) method using the B3LYP function with 6-31G(d,p) as the basis set. A detailed interpretation of the Infrared and Raman spectra of TDZ was reported based on Potential Energy Distribution (PED). The first order hyperpolarizability (β(0)) of this novel molecular system and related properties (β, α(0) and Δα) were calculated using HF/6-31G(d,p) method on the finite-field approach. Stability of the molecule arising from hyperconjugative interactions and charge delocalization have been analyzed using Natural Bond Orbital analysis. The results show that charge in electron density in the σ(∗) and π(∗) antibonding orbitals and second order delocalization energies E(2) confirm the occurrence of Intramolecular Charge Transfer (ICT) within the molecule. UV-Vis spectrum of the title molecule was recorded and the electronic properties such as HOMO and LUMO energies were determined by Time-Dependent Density Functional Theory approach.

Effect of cytokinins on in vitro multiplication of Sophora tonkinensis.

OBJECTIVEnTo determine the effects of different cytokinins at various concentrations on in vitro shoot multiplication of an important medicinal plant.nnnMETHODSnNodal explants (1.5-2.0 cm) of Sophora tonkinensis were used. Multiple shoots were induced from nodal explants cultured on the Murashige and Skoog (MS) medium supplemented with 0.0, 0.5, 1.0, 2.0, 4.0, 8.0, or 16.0 µmol 2-isopentyladenine (2iP), N6 benzyladenine, kinetin or thiadiazuron.nnnRESULTSnAmong the four investigated cytokinins, 2iP showed the best response for shoot multiplication. Maximum shoot induction (75%) was achieved on the MS medium supplemented with 2.0 µmol 2iP, with a mean number of 5.0 shoots per explant. In comparison to other cytokinins tried, 2iP showed the highest shoot elongation with a mean shoot length of 4.8 cm. Root initiation was observed within 15 d within the transfer of shoots onto the MS basal medium, and the rooting percentage was 100% with a mean number of 5.4 roots per shoot and root length of 6.2 cm over a period of 4 weeks. The healthy plants, hardened and transferred to a greenhouse for proper acclimatization, exhibited 100% survival.nnnCONCLUSIONSnIt can be summarized that 2iP is the optimal plant growth regulator for Sophora multiplication.

Identification of somaclonal variants in proliferating shoot cultures of Senecio cruentus cv. Tokyo Daruma

A protocol for in vitro propagation of cineraria (Senecio cruentus) was developed. The highest frequency of shoot proliferation was obtained from nodal explants cultured on Murashige and Skoog (MS) medium supplemented with 2.0xa0mg L−1 6-benzyladenine (BA) and 0.5xa0mg L−1 α-naphthalene acetic acid (NAA), with a mean number of 14 shoots per explant. A high concentration of BA (4.0xa0mg L−1) and repeated subcultures resulted in hyperhydric shoots. Decreasing the BA concentration to 1.0xa0mg L−1 in the culture medium eliminated hyperhydricity. The concentration of ammonium nitrate (NH4NO3) and temperature had marked effects on somaclonal variation. Variation was observed when the cultures were maintained at 15xa0°C but not at 25xa0°C. Variants with blue-colored leaves and stems were identified; whereas, normal plants maintained their green-colored leaves and stems. The highest frequency of variation (67.5xa0%), with a mean number of 3.0 variant shoots per explants, was obtained on shoot proliferation medium (MSxa0+xa02.0xa0mg L−1 BA and 0.5xa0mg L−1 NAA) devoid of NH4NO3. The best rooting (100xa0%), with the highest number of roots per shoot (10.8) and the greatest root length (6.8xa0cm) was obtained on medium supplemented with 0.1xa0mg L−1 NAA. In vitro-grown plantlets were successfully acclimatized in a greenhouse, and transferred to the field.

Enhancing salt tolerance in eggplant by introduction of foreign halotolerance gene, HAL1 isolated from yeast

Agrobacterium-mediated gene transfer method for production of transgenic eggplants (Solanum melongena L. var. PKM1) has been optimized. Polymerase chain reaction of transgenic plants confirmed the presence of the expected HAL1 fragment. Different tests were carried out to evaluate the level of salt tolerance for the transgenic and control plants with culture media in vitro (0, 50, 100, 150, or 200 mM NaCl) and with soil in greenhouse (0, 25, 50, 75, or 100 mM NaCl). Differences in callus growth between transgenic and control lines were observed. At 150 mM NaCl, the weight of calli from the transgenic population did not differ significantly from that in non salt condition, while the growth of wild-type control calli was strongly inhibited. A preliminary evaluation in vivo under controlled greenhouse conditions showed that at moderate salt concentrations (25 mM NaCl), a similar response to salinity in the original line and in the transgenic progeny was found. However, at higher salt concentration (50 mM NaCl), total dry weight (relative growth) was not significantly decreased by salinity in the transgenic population, while a growth reduction was observed in the wild-type control. Our results indicated that a higher level of salt tolerance was found in the transgenic lines than in the wild-type control. Thus, in this present study we have demonstrated the possibility of increasing salt tolerance in eggplant by introducing the foreign gene, HAL1 derived from yeast.

Short-Term Ion Uptake by Phalaenopsis as Affected by Concentration of the Solution

ABSTRACT Nutrient uptake over a 72 h culture period by clonal micropropagules of Phalaenopsis Tanigawa × Yukimai Dream ‘KS 370’ and ‘KS 352’ were surveyed by Ichihashis (1997) nutrient solution at the original ion strength and its half and quarter. Uptake of major anions [nitrate (NO3 −), phosphate (H2PO4 −), and sulfate (SO4 2−)] and cations [ammonium (NH4 +), potassium (K+), calcium (Ca2+), and magnesium (Mg2+)] measured with an ion chromatograph increased as the ionic strength of the solution increased in both cultivars. The final uptake rates of nutrients were 0.8, 2.0, 2.1, 1.2, 3.0, 2.0, and 1.6 me L−1, respectively in the order of ions mentioned above. The ratios of the uptake rates between cations (mono or bivalent) were almost in proportion to the ratio of their initial ion strength. Therefore, no antagonistical absorption of cations was found in that ion strength. Leaf content of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and copper (Cu) increased as the ionic strength of the solution increased, but concentrations of iron (Fe), manganese (Mn), and zinc (Zn) were not affected significantly. Nitrogen (N) content of leaves in ‘KS 370’ after 72 h culture increased significantly by increasing the ionic strength of the solution. Root concentrations of P, K, Ca, Mg, and Fe increased as the ionic strength of the solution increased in both cultivars. The N concentrations of roots in either ‘KS 370’ or ‘KS 352’ had positive correlations with an increasing ionic strength of the solution, although they were constantly greater in ‘KS 370’ than in ‘KS 352’. The greatest fresh weight was obtained when the plants were cultured in a half strength solution. Whereas dry weight decreased in all treatments as the ionic strength of the solution decreased. These findings show that increased ion absorption affected plant dry weight. The obtained findings provide fundamental information for the closed hydroponic system of phalaenopsis cultivation.