Shoots

A complete protocol is presented for the first time for the micropropagation of Pongamia pinnata, a biofuel tree, using cotyledonary nodes derived from axenic seedlings. Multiple shoots were induced in vitro from nodal segments through forced axillary branching. Murashige and Skoog (MS) medium supplemented with 7.5 μM benzylaminopurine (BAP) induced up to 6.8 shoots per node with an average shoot length of 0.67 cm in 12 d. Incorporation of 2.5 μM gibberellic acid (GA3) in the medium during the first subculture after establishment and initiation of shoot buds significantly improved the shoot elongation. Single use of GA3 during the first subculture eliminated the need for prolonged culturing on BAP medium. Further use of GA3 in the medium was not useful. Shoot culture was established for at least two subcultures without loss of vigor by repeatedly subculturing the original cotyledonary node on shoot multiplication medium followed by shoot elongation medium after each harvest of the newly formed shoots. Thus, from a single cotyledonary node, about 16–18 shoots were obtained in 60 d. Shoots formed in vitro were rooted on full-strength MS medium supplemented with 1.0 μM indole butyric acid (IBA). Plantlets were successfully acclimated, established in soil, and transferred to the nursery.

An efficient regeneration protocol for rapid multiplication of Melia azedarach, an economically as well as medicinally important timber-yielding tree, was developed. Nearly 90% of the culture exhibited axillary bud sprouting and multiple shoot formation from nodal segments derived from 20-year-old candidate plus tree on Murashige and Skoog (MS) medium supplemented with 5 μM 6-benzyladenine (BA). The highest shoot regeneration frequency (92%), maximum number of multiple shoots (19.7 ± 0.31) as well as shoot length (4.9 ± 0.08 cm) was induced from nodal explants on MS medium amended with 5.0 μM BA, 0.5 μM indole-3-acetic acid (IAA) and 30 μM adenine sulfate (AdS). Addition of 250 mg l−1 ammonium sulphate, (NH4)2SO4, and 100 mg l−1 K2SO4, prevented defoliation and tip burning without affecting the number of shoots. The explant harvest period also influenced the bud break and shoot sprouting from nodal segments. Repeated subculturing of nodal explants on fresh MS medium containing lower concentration of BA (2.5 μM) along with IAA (0.5 μM), AdS (30 μM) and additives was found most suitable growth regulator regime for achieving 1.2-fold increase in shoot multiplication rate. The percentage of shoot multiplication as well as the number of shoots per node remained the same during first three subculture passages, afterwards a decline was recorded. About 90% of the in vitro regenerated shoots were successfully rooted ex vitro by giving a pulse treatment of 250 μM indole-3-butyric acid for 15 min, followed by their transfer to thermocol cups containing soilrite. The raised plantlets were successfully acclimatized first under culture room conditions, then to green house with 85% survival rate.

Abstract. Nowadays, the plant biodiversity is threatened and its conservation represents a priority at the international level. Conservation strategies are based on the management of wild populations in nature, but they require additional methods of ex situ conservation ...

In vitro shoots of sage (Salvia officinalis L.) were established under four different cytokinin supplementations by culturing nodal segments excised from aseptically germinated seedlings. The highest rates of shoot proliferation and linear shoot growth occurred with the supplementation of 1.5 mg/l benzyladenine and 0.05 mg/l dichlorophenoxyacetic acid. However, under these conditions, the specific production of total antioxidant phenolics was the lowest. Variation in kinetin (KIN) concentration (1.5; 2.0; 4.0 mg/l), in the presence of 0.05 mg/l 2,4-D, did not influence significantly the rates of shoot proliferation and linear shoot growth but influenced the production of antioxidant phenolics and biomass. Seventeen compounds were identified in the antioxidant phenolic extracts from shoots: gallic acid, 3-O-caffeoylquinic acid, 5-O-caffeoylquinic acid, caffeic acid, and rosmarinic acid, as phenolic acids; hesperetin, apigenin, hispidulin, cirsimaritin, and genkwanin, as flavonoids; epirosmanol, epirosmanol methyl ether, carnosol, epiisorosmanol ethyl ether, rosmadial, carnosic acid, and methyl carnosate, as phenolic diterpenes. With exception of carnosic acid and methyl carnosate, all the other phenolic compounds (15) were also identified in a commercial sample of this species. Rosmarinic acid and carnosol were the main compounds in all the antioxidant phenolic extracts. The increase in concentration of KIN decreased the accumulation of the most of phenolic diterpenes, particularly that of carnosol.

BACKGROUND: There is growing interest among consumers in baby leaf vegetables, mostly requested for mixed salads, both as fresh market products and ready-to-use vegetables. Fertilisation is one of the most practical and effective ways of controlling and improving the yield and nutritional quality of crops for human consumption. The optimal fertiliser concentration for baby leaf vegetables depends on the environmental conditions. The aim of the present work was to determine the effects of nutrient solution concentration (2, 18, 34, 50 or 66 mequiv L−1) during two consecutive growing seasons (spring and summer) on the yield and leaf quality of Lactuca sativa L. var. acephala grown in a floating system.RESULTS: Marketable fresh yield, total dry biomass, leaf area index, macroelement (N, P, K and Mg) concentrations and nitrate and total chlorophyll contents increased in response to an increase in nutrient solution concentration, while the opposite trend was observed for root/shoot ratio and glucose, fructose, starch, total carbohydrate and protein contents. Plants grown in the spring season exhibited lower yield and growth (total dry biomass and leaf area index) but higher leaf quality (higher carbohydrate content and lower nitrate content) than those grown in the summer season.CONCLUSION: The use of nutrient solution concentrations of 37 and 44 mequiv L−1 for the spring and summer seasons respectively could be adopted in the present conditions to improve marketable fresh yield and leaf mineral content, but with a slight reduction in some nutritional parameters. Copyright © 2009 Society of Chemical Industry

A simple, high frequency, and reproducible method for plant regeneration through direct organogenesis from cotyledonary leaf explants of Jatropha curcas was developed using Murashige and Skoog (MS) medium supplemented with different concentrations of thidiazuron (TDZ) or 6-benzyl aminopurine (BAP). Medium containing TDZ has greater influence on regeneration as compared to BAP. The induced shoot buds were transferred to MS medium containing 10 μM kinetin (Kn), 4.5 μM BAP, and 5.5 μM α-naphthaleneacetic acid (NAA) for shoot proliferation. The proliferated shoots could be elongated on MS medium supplemented with different concentrations and combinations of BAP, indole-3-acetic acid (IAA), NAA, and indole-3-butyric acid (IBA). MS medium with 2.25 μM BAP and 8.5 μM IAA was found to be the best combination for shoot elongation. However, significant differences in plant regeneration and shoot elongation were observed among the genotypes studied. Rooting was achieved when the basal cut end of elongated shoots were dipped in half strength MS liquid medium containing different concentrations and combinations of IBA, IAA, and NAA for 4 days, followed by transfer to growth regulators free half strength MS medium supplemented 0.25 mg l−1 activated charcoal. Elongated shoot treated with 15 μM IBA, 5.7 μM IAA, and 11 μM NAA resulted in highest percent rooting. The rooted plants could be established in soil with more than 90% survival rate. The method developed may be useful in improvement of J. curcas through genetic modification.

The diversity of arbuscular mycorrhizal (AM) fungi of Acacia catechu Willd. was studied. Dominant AM spores, the bacterium Rhizobium sp. along with the fungus Trichoderma viride were isolated from the rhizosphere of A. catechu and mass-produced in laboratory. The co-inoculation effect of Glomus mosseae, Glomus fasciculatum, mixed AM (Glomus spp. [except G. mosseae, G. fasciculatum] with Acaulospora spp., Sclerocystis spp. and Gigaspora spp.), Rhizobium sp. and Trichoderma viride was studied as exerted on the growth of A. catechu seedlings. All inoculated seedlings showed improved seedling growth compared to the control. Inoculated seedlings had a pronounced effect on all growth parameters such as height, fresh and dry weight of roots and shoots, AM spore count, per cent mycorrhizal colonization in roots and root nodule number in comparison with uninoculated seedlings. Phosphorus uptake was also higher in inoculated seedlings than in the control. This study provides a good scope for ...

In a field experiment with leek, four forms of green manuring with red clover were compared; direct incorporation, biogas residue, compost and green mulch. The application rates were based on concentrations of nitrogen (N) and carbon (C) in the clover roots and shoots in the direct incorporation treatment, and the N-availability. A practically appropriate mulch application rate was included for

En busca de proteger el recurso forestal de Cedrela odorata L., actualmente amenazado, se planteó la necesidad de establecer un proto- colo para su crioconservación; la investigación se realizó con ápices y semillas. Con los ápices se evaluó la técnica de vitrificación a través de varias soluciones vitrificadoras y congelamiento rápido en nitrógeno líquido (NL). Inicialmente los mejores resultados se obtuvieron al evaluar la incubación en la solución PVS3 por 5 min antes del congelamiento, con una sobrevivencia del 61% después de 3 semanas de cultivo en el medio Murashige y Skoog (MS) con 1,0 mg.l-1 BAP y 0,1 mg.l-1 AG3. Por otra parte, al incubar los ápices en una solución 0,3 M de sacarosa por 5 min previo al congelamiento, el porcentaje de sobrevivencia alcanzó 86% después de 2 semanas de cultivo en un medio MS con 1,0 mg.l-1 BAP, 0,1 mg.l-1 AG3 y 0,01 mg.l-1 AIA. Cuando se utili- zó la incubación en la solución de 0,3 M sacarosa y el medio de recuperación MS con 1 mg.l-1 KIN, 0,...