Actions for ex situ conservation of Gloriosa superba L. - an endangered ornamental cum medicinal plant

Factors affecting in vitro propagation and microtuberization were evaluated for Gloriosa superba L., an endangered ornamental cum medicinal plant having limited reproductive capacity. Surface sterilization of tuber explants with 0.1% mercuric chloride (HgCl₂) for 5 min eliminated the contamination effectively with highest survival rate. Among the various combinations used, Murashige and Skoog (MS) medium with 2.0 mg L^?1 6-benzylaminopurine (BAP) + 0.5 mg L^?1 α-naphthalene acetic acid (NAA) containing 3% sucrose with 16-h photoperiod exhibited the greatest in vitro tuberization (3.2) with the highest shoot regeneration frequency (90%). The longest tuber regeneration occurred on MS media containing 4% sucrose. Transfer of in vitro-regenerated shoots to half-strength MS medium with 1.0 mg L^?1 indole-3-butyric acid (IBA) + 0.5 mg L^?1 NAA showed maximum root induction (66.6%). The in vitro-grown plantlets were successfully acclimatized and transplanted to sterilized soil and sand mixture (3:1) in the glasshouse with 70% survival. The colchicine content was determined in the tubers of ex vitro plants by HPLC using the same retention time (1.5 min) as that of the standard colchicine. This revealed that the micropropagation protocol developed by us for rapid mass production could be used as raw material for colchicine extraction and provides a basis for germplasm conservation and genetic improvement of G. superba.     

Influence of crops, crop residues and manure on amino acid and amino sugar fractions of organic nitrogen in soil

A field experiment was carried out to study the effect of: (1) the cultivation of a cereal (pearl millet) and two legumes (mung bean and clusterbean), and (2) incorporation of crop residues and manure in soil, on depletion or enrichment of pools of amino acid-N and amino sugar-N in soil. Both legumes enriched amino acid and amino sugar fractions but pearl millet cultivation depleted them. Enrichment of these fractions was partly attributed to the conversion of N biologically fixed during legume cultivation to these fractions and partly to the conversion of unknown and non-hydrolysable N fractions to amino acid-N and amino sugar-N. Mineralization of amino acid-N and amino sugar-N fractions along with their conversion to unknown and non-hydrolysable fractions were the plausible reasons for the decline in their concentrations after pearl millet cultivation. Application of residues or manure reversed this effect of pearl millet.     

InfoCrop: A dynamic simulation model for the assessment of crop yields,losses due to pests,and environmental impact of agro-ecosystems in tropical environments. II. Performance of the model

InfoCrop, a generic crop model, simulates the effects of weather, soils, agronomic management (planting, nitrogen, residues and irrigation) and major pests on crop growth, yield, soil carbon, nitrogen and water, and greenhouse gas emissions. This paper presents results of its evaluation in terms of its validation for rice and wheat crops in contrasting agro-environments of tropics, sensitivity to the key inputs, and also illustrates two typical applications of the model. Eleven diverse field experiments, having treatments of location, seasons, varieties, nitrogen management, organic matter, irrigation, and multiple pest incidences were used for validation. Grain yields in these experiments varied from 2.8 to 7.2 ton ha⁻¹ in rice and from 3.6 to 5.5 ton ha⁻¹ in wheat. The results indicated that the model was generally able to explain the differences in biomass, grain yield, emissions of carbon dioxide, methane and nitrous oxides, and long-term trends in soil organic carbon, in diverse agro-environments. The losses in dry matter and grain yield due to different pests and their populations were also explained satisfactorily. There were some discrepancies in the simulated emission of these gases during first few days after sowing/transplanting possibly because of the absence of tillage effects in the model. The sensitivity of the model to change in ambient temperature, crop duration and pest incidence was similar to the available field knowledge. The application of the model to quantify multiple pests damage through iso-loss curves is demonstrated. Another application illustrated is the use of InfoCrop for analyzing the trade-offs between increasing crop production, agronomic management strategies, and their global warming potential.     

Changes in plant water status of Maize (Zea mays L.) with ontogeny

Summary Irrigations scheduled on plant water status ignore the effect of ontogeny on plant water status. Leaf xylem water potential (XWP) of maize sown on three dates in a sandy loam soil was measured under the same environment for evaluating the effect of ontogeny on plant water status. Minimum XWP (measured between 13.00-14.30 h) of the youngest crop was the highest during two crop seasons and the differences in XWP of the youngest and the oldest maize plants ranged from 0.25 to 0.65 MPa during the season. Maximum XWP (measured before dawn) of the youngest crop was nearly 0.1 MPa higher than that of the oldest crop. Diurnal variation in XWP was lowest in the youngest crop. The results highlight the need of ontogeny dependent critical values of plant water status for scheduling irrigation.     

Abundance and diversity of arthropods in transgenic Bt and non-Bt cotton fields under Indian conditions

Phytoparasitica - Two-year field studies during Kharif 2015 and 2016 were conducted to assess the abundance and diversity of arthropod communities of Bt cotton carrying Cry1Ac and Cry2Ab proteins...     

The infestation of Vicia faba L. (Fabaceae) by Aphis fabae (Scop.) (Homoptera: Aphididae) under the influence of Lamiaceae (Ocimum basilicum L. and Satureja hortensis L.)

Abtract The system Vicia faba–Aphis fabae fabae was studied under the influence of Ocimum basilicum (basil) and Satureja hortensis, in a wind tunnel, in the greenhouse and in field experiments. In the wind tunnel at 20°C both Lamiaceae were deterrent for A. fabae, and S. hortensis proved to be more deterrent than O. basilicum. In experiments in the greenhouse at low temperatures (average minimum 14.6°C, average maximum 24.1°C), A. fabae colonised first and significantly more intense Vicia fabae (field beans) not surrounded by O. basilicum or S. hortensis. At high temperatures (average minimum 18.0°C, average maximum 38.5°C) this relation was inverted: Vicia faba surrounded by the two Lamiaceae were preferred for colonisation (Ocimum basilicum significantly). It showed that pots with Lamiaceae were no obstacle for the aphids to reach Vicia faba. In strip cropping in the field, the repellent effect of Ocimum basilicum proved to be stronger than of Satureja hortensis. In 2002 there was observed only a tendency of lower aphid attack of field beans intercropped with Lamiaceae, while in 2004 and 2005 the infestation of Vicia faba by Aphis fabae was significantly lower in plots intercropped with basil. In plots with Satureja hortensis as intercrop, Vicia faba were significantly lower infested, after 3 weeks. The differences between the results of the wind tunnel/greenhouse at low temperatures, and the field experiments concerning the deterrence by Satureja hortensis cannot be explained. But basing on our results with Ocimum basilicum and those published by other authors, it is recommended to follow up intercropping, after a sincere analysis in every case, in favour of agronomists.     

Biological nitrogen fixation at elevated temperature in different Azospirillum species and strains

Nitrogenase activity, nitrogenase synthesis, and the growth of four species of Azospirillum were examined at 30°C and 42°C. Azospirillum brasilense Sp 7 did not synthesize nitrogenase at 42°C nor was the enzyme stable at this temperature. In A. lipoferum 708 and A. brasilense 12S the nitrogenase activity was stable at 42°C but the synthesis of nitrogenase was reduced. In A. brasilense Sp 9 the nitrogenase activity was stable and showed the highest C₂H₂ reduction activity at 42°C.     

Biodegradable alginate microspheres as a delivery system for naked DNA.

Sodium alginate is a naturally occurring polysaccharide that can easily be polymerized into a solid matrix to form microspheres. These biodegradable microspheres were used to encapsulate plasmid DNA containing the bacterial beta-galactosidase (LacZ) gene under the control of either the cytomegalovirus (CMV) immediate-early promoter or the Rous sarcoma virus (RSV) early promoter. Mice inoculated orally with microspheres containing plasmid DNA expressed LacZ in the intestine, spleen and liver. Inoculation of mice with microspheres containing both the plasmid DNA and bovine adenovirus type 3 (BAd3) resulted in a significant increase in LacZ expression compared to those inoculated with microspheres containing only the plasmid DNA. Our results suggest that adenoviruses are capable of augumenting transgene expression by plasmid DNA both in vitro and in vivo.