4 research outputs found

    Production of artificial seeds derived from encapsulated in vitro micro shoots of cauliflower, Brassica oleracea var. botrytis

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    A high number of micro shoots (21 +/- 2.31) of Brassica oleracea var. botrytis (cauliflower) were obtained when hypocotyl explants from 2-week-old aseptic seedlings were cultured on MS medium supplemented with 0.1 mg/L NAA and 5 mg/L BAP. Artificial or synthetic seeds were formed when the micro shoots were encapsulated in 4 (w/v) sodium alginate with 100 mM CaCl2 as complexing solution. The artificial seeds took 12 days (after 7 days storage) and 14 days (after 30 days storage) to germinate on MS basal medium. The germination percentage of artificial seeds was enhanced by the inclusion of 0.3 mg/L NAA and 3.0 mg/L BAP in the encapsulation matrix after 7 and 30 days of pre-germination storage. The time taken for germination was also faster (5 days after 7 days of storage and 11 days after 30 days of storage) when MS fortified with 0.3 mg/L NAA and 3.0mg/L BAP were used. Isolated micro shoots encapsulated in MS supplemented with 0.3 mg/L NAA and 3.0mg/L BAP gave high germination percentages (70 +/- 5.43 and 63.33 +/- 4.17) after 7 and 30 days of pre-germination storage period, respectively. Complete plant regeneration was achieved from the germination of these artificial seeds derived from the micro shoots after 3-4 weeks in culture

    Somatic embryogenesis and plant regeneration from hypocotyl and leaf explants of Brassica oleracea var. botrytis (cauliflower)

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    We investigated direct and indirect formation of somatic embryogenesis in Brassica oleracea var. botrytis (cauliflower), a very important vegetable crop worldwide. Direct somatic embryogenesis, which is rather rare, was achieved in culture of 2-week-old hypocotyl explants of Brassica oleracea var. botrytis on MS medium supplemented with 1.0 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5; 1.0; and 1.5 mg/l kinetin. Initial induction of embryogenic callus was achieved on MS supplemented with very low concentrations of 2,4-D (0.05 mg/l and 0.1 mg/l). Indirect somatic embryogenesis from leaf sections was obtained on MS supplemented with 0.05 or 0.1 mg/l 2,4-D. We examined various stages of somatic embryos (globular, heart, torpedo, cotyledonary). More embryos per explant were produced through the indirect pathway (23–25) than through the direct pathway (14–19). The number of embryos produced was high. There is a potential for recurrent, repeated or secondary somatic embryogenesis, possibly an unlimited source for mass propagation and ideal for synthetic seed production in this species. Plant regeneration was achieved on half-strength MS medium without any hormones

    Large estragole fluxes from oil palms in Borneo

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    During two field campaigns (OP3 and ACES), which ran in Borneo in 2008, we measured large emissions of estragole (methyl chavicol; IUPAC systematic name 1-allyl-4-methoxybenzene; CAS number 140-67-0) in ambient air above oil palm canopies (0.81 mg m−2 h−1 and 3.2 ppbv for mean midday fluxes and mixing ratios respectively) and subsequently from flower enclosures. However, we did not detect this compound at a nearby rainforest. Estragole is a known attractant of the African oil palm weevil (Elaeidobius kamerunicus), which pollinates oil palms (Elaeis guineensis). There has been recent interest in the biogenic emissions of estragole but it is normally not included in atmospheric models of biogenic emissions and atmospheric chemistry despite its relatively high potential for secondary organic aerosol formation from photooxidation and high reactivity with OH radical. We report the first direct canopy-scale measurements of estragole fluxes from tropical oil palms by the virtual disjunct eddy covariance technique and compare them with previously reported data for estragole emissions from Ponderosa pine. Flowers, rather than leaves, appear to be the main source of estragole from oil palms; we derive a global estimate of estragole emissions from oil palm plantations of ~0.5 Tg y−1. The observed ecosystem mean fluxes (0.44 mg m−2 h−1) and mean ambient volume mixing ratios (3.0 ppbv) of estragole are the highest reported so far. The value for midday mixing ratios is not much different from the total average as, unlike other VOCs (e.g. isoprene), the main peak occurred in the evening rather than in the middle of the day. Despite this, we show that the estragole flux can be parameterised using a modified G06 algorithm for emission. However, the model underestimates the afternoon peak even though a similar approach works well for isoprene. Our measurements suggest that this biogenic compound may have an impact on regional atmospheric chemistry that previously has not been accounted for in models and could become more important in the future due to expansion of the areas of oil palm plantation
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