Seed germination and in vitro regeneration of the African medicinal and pesticidal plant, Bobgunnia madagascariensis

Propagation of the medicinal and pesticidal tree, Bobgunnia madagascarensis is difficult due to poor and erratic germination of its seeds and slow growth of its seedlings. This study involved two separate experiments. The first evaluated the effect of pre-sowing treatments and growing medium on ex vitro seed germination and early seedling development. The second experiment involved in vitro germination, shoot initiation and rooting of shoots. Pre-sowing seed treatments involved soaking seeds in cold and hot water for 12 and 24 h and soaking in different concentrations (0, 100, 200, 400 and 800 mg/l) of gibberellic acid for 24 h. Soaking of seeds in cold or hot water for up to 24 h did not achieve more than 45% germination, while seeds treated with gibberellic acid achieved 76%) when seeds were sown in a growing medium without compost compared with a medium with compost (<43%). All shoot-tips isolated from the in vitro germinated seedlings on B5 media without plant growth regulators continued to grow as a single shoot, while shoot-tips cultured on B5 supplemented with 0.1 mg/l of naphthaleneacetic acid (NAA) and thidiazuron (TDZ) produced two shoots each after four weeks. It was concluded that B. madagascariensis seeds had very low ex vitro germination percentages. Although, in vitro cultures improved seed germination, axillary shoot multiplication and rooting were not satisfactory. Therefore, further studies are needed to develop an optimal in vitro multiplication protocol for B. madagascariensis

Numerical modelling of heat transfer in a tube furnace for steel wire annealing

In order to relieve stresses from cold drawing and to regain ductility, steel wires are annealed in furnaces under prolonged exposure to an appropriate temperature termed as ‘soaking’. This ensures the attainment of the required product quality. Literature suggests that the annealing processes are still determined by trial and error approach due to a lack of standards and also due to the proprietary nature of furnace designs. This paper investigates the heat transfer mechanism in a 12-metre long tube furnace filled with an inert gas and through which a cold-rolled steel wire travels at a specified speed. The length of the furnace is divided into three regions i.e. heating zone, soaking zone and cooling zone of which the heating and the cooling zones are given special attention. The methodology involves the use of Computational Fluid Dynamics by coupling both solid (steel wire) and gaseous zones (Hydrogen or Nitrogen). Radiation has been incorporated via a suitable model and convection taken care of by considering laminar flow of gases. The results suggest that the time needed in the heating zone is influenced by the choices of the surrounding atmosphere, speeds of gas and of the wire. These factors have an impact on the wire drawing speed and eventually on the overall productivity. It is also implied that the proposed numerical method may be used to shorten the ‘soaking’ time and hence to reduce energy consumption. The work demonstrates the usefulness of CFD in understanding and optimisation of the transfer process as well as highlights the challenges associated with numerical results

Pemanfaatan Serbuk Kayu Jati (Tectona Grandis L.) Yang Direndam Dalam Air Dingin Sebagai Media Tumbuh Jamur Tiram (Pleurotus Comunicipae)

The growth responds of Pleurotus comunicipae to the use of cold water-soaked teakwood sawdust as a growth medium was investigated. Teakwood sawdust was soaked in cold water during the time periods of 1, 3, 5 and 7 days) with ten replications. Unsoaked teakwood sawdust was also prepared and used as a control. Measurement variabels consisted of time required for a completely covering mycelial growth, number of fruitbody, and fungal mass (green and dry weight). Results showed that P. comunicipae placed on soaked teakwood sawdust medium had a better growth than control (without soaking) medium. The medium with increased soaking period produced a good growth ability of P.comunicipae. At teakwood sawdust soaked for 7 days, the average of mycelial growth to cover teakwood sawdust medium, number of fruiting bodies, green weight and dry weight at the first harvesting were 52.6 days, 8.6 units, 100.5 grams and 13.4 grams, respectively. Keywords: teakwoods sawdust, Pleurotus comunicipae, cold water soaking, growth abilit

Influence of salicylic acid on phytochelatin synthesis in Zea mays during Cd stress

Abstract: Presoaking maize (Zea mays) seeds in salicylic acid (SA) reduces damage caused by cadmium. In the present work the possible role of phytochelatins (PCs) in SA-mediated protection against Cd toxicity was investigated. Seeds were presoaked in 0.5 mM SA, and seedlings were grown in hydroponic solution containing 0, 0.01, 0.015, or 0.025 mM Cd. Treatment with Cd increased the PC levels in maize roots, but only slight changes were observed in the leaves. Long-term exposure to Cd decreased the phytochelatin synthase (PCS) activity in the roots and led to an increase in PCS and glutathione reductase (GR) activities in maize leaves. Although presoaking seeds in SA solution before exposure to Cd may reduce the level of heavy metal injury and has an effect on the composition of individual PCs, this protection is not directly connected with the altered regulation of PCs

EPI Update, September 11, 2009

Weekly newsletter for Center For Acute Disease Epidemiology of Iowa Department of Public Health

Low Shrinkage Bleaching of Unbleached Neutral Sulphite Semichemical Pulp

The main objective of this research project was the investigation of the most feasible method for the bleaching of a soft-cooked unbleached neutral sulphite semichemical aspen pulp cooked to a 70 percent yield. Furthermore, treatment of unbleached, laboratory bleached and commercially bleached neutral sulphite semichemical pulp with a new chemical, sodium borohydride, was also carried out. The results of our experimental work showed that, the best bleaching procedure was when 15 percent chlorine as hypochlorite was used in the first stage, followed by a hydrochloric acid soaking stage with a final treatment of 2.6 percent hydrogen peroxide. With the above procedure brightness values over 80 percent were obtained with the yields in the 90 percent range based on the weight of the pulp. Sodium borohydride treatment of the three pulps showed that, with regards to ultra-violet light and heat stability the chemical, sodium borohydride, had no effect on the unbleached and the bleached lignin-containing pulps. Treatment of the commercially bleached, lignin-free, pulp however showed that the chemical had a marked effect in improving the heat and light stability of the pulp. It was noted that with all three types of pulp the chemical sodium borohydride did procedure a bleaching effect

Phosphorus in pig diets

Pig feed is mainly based on cereals where phosphorus (P) is mostly present in inositol hexaphosphate (IP6), which is not readily available to monogastric animals. More available P sources are often added to ensure that pigs’ requirements are fulfilled; this results in high excretion levels of P. The digestibility of P depends on phytase activity and amount of IP6 in feedstuffs. The overall aim was to study effects of liquid feeding, P levels and phytase supplementation on digestibility and performance. Effects of soaking and P levels on digestibility were studied by total collection in metabolic cages, and effects on performance were studied in 192 growing pigs. Effects of soaking fermentation and phytase supplementation on ileal and total tract digestibility were studied with indicator technique on pigs surgically fitted with PVTC cannulas. P levels and phytase supplementation were studied in 104 pregnant sows for two reproduction cycles. All diets were cereal based and included wheat. Basic properties of a cereal mix fermented with whey, wet wheat distillers’ grain and water in different temperatures were also studied. Soaking reduced the level of IP6, whereas apparent digestibility of P was not significantly improved. Soaking increased average daily weight gain, carcass weights and improved the energy conversion ratio in pigs fed a low P diet to the same level as pigs fed high P diets. Low P diets resulted in lower femur density than high P diets. However, soaking of a low P diet resulted in increased femur density. Fermentation degraded IP6 efficiently and improved ileal apparent digestibility of P, organic matter, nitrogen, amino acids and total tract apparent digestibility of organic matter. Microbiological and biochemical properties of fermented liquid diets are strongly affected by feed components and temperature used. Phytase supplementation slightly affected apparent digestibility of P. Supplementing a low P gestation diet with phytase did not significantly affect sow performance. The slight effects of phytase supplementations found may depend on high levels of intrinsic phytase in the diets, and possibly suggest that the provided P level in the sows may have been sufficient. Under typical Swedish conditions of sow management, reduced total P level in gestation diets seems not to negatively affect performance