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Accueil du site → Doctorat → Australie → 2013 → Millettia pinnata (L.) Panigrahi a biodiesel tree, characterisation of traits for production on marginal land

University of Western Australia (2013)

Millettia pinnata (L.) Panigrahi a biodiesel tree, characterisation of traits for production on marginal land

Arpiwi, Ni Luh

Titre : Millettia pinnata (L.) Panigrahi a biodiesel tree, characterisation of traits for production on marginal land

Auteur : Arpiwi, Ni Luh

Université de soutenance : University of Western Australia

Grade : Doctor of Philosophy (PhD) 2013

Résumé partiel
The leguminous tree, Millettia pinnata (L.) Panigrahi syn. Pongamia pinnata (L.) Pierre produces oilseed suitable for biodiesel production. It is targeted for planting on marginal lands associated with salinity, waterlogging and nitrogen-poor soils. Superior genotypes are required for oil production and in this study genetic diversity, seed traits and salinity tolerance were assessed. Seeds from the Forest Products Commission trials in Kununurra, northern Western Australia were compared with those from Queensland and the Northern Territory in Australia, India and Indonesia. Genetic diversity, examined using the internal transcribed spacer region, indicated distinctiveness of genotypes from Java, Indonesia. Seed traits varied between trees with the smallest seeds from Indonesia and the biggest from Western Australia. Oil content also varied with a minimum of 28% in an Indonesian accession and the highest of 45% from Kununurra. Across trees, fatty acid composition was predominantly oleic acid (51%) with linoleic (19%), palmitic (11%) stearic (6%), behenic and linolenic (4.5% respectively), and small amounts of lignoceric (1.4%), 11-eicosenoic and arachidic acids (both at 1.2%), and this composition is suitable for biodiesel. At 11 months after flowering, seed had reached maximum weight, they contained the highest oil content, seed oil had the highest proportion of oleic acid, and this was an ideal time for harvest. Waterlogging and salinity tolerance were assessed. Four month-old seedlings from Kununurra and India were exposed to four treatments : non-saline drained control, saline drained, non-saline waterlogged and saline waterlogged. Salt was applied in weekly increments of 50 mM NaCl.

Salt treatment reduced survival, height growth rate, leaf number and stomatal conductance and increased concentrations of Na+ and Cl- in leaves. Salinity tolerance was 200 mM NaCl under saline drained and 150 mM NaCl under saline waterlogged conditions. Seedlings tolerated non-saline waterlogged conditions. Millettia pinnata could be suitable for biodiesel production on marginal land under these conditions. Symbiosis of M. pinnata with root nodule bacteria for nitrogen fixation was investigated. Soil samples were collected from the base of M. pinnata grown in plantations in Kununurra, tropical northern Western Australia and rhizobia were trapped and isolated. Forty pure isolates were obtained and optimum growth conditions were pH 7 – 9, temperatures of 29 - 37oC and salinity less than 1% NaCl. Most isolates had optimal growth on mannitol, arabinose or glutamate as a single carbon source, a few grew on sucrose and none grew on lactose. Ten isolates with relative effectiveness of 60 - 86% were selected for genotyping using sequencing of 16S rRNA, atpD, dnaK and recA genes. Six slow-growing isolates were assigned to Bradyrhizobium yuanmingense, two were unknown Bradyrhizobium closely related to Bradyrhizobium sp. DOA10 and Bradyrhizobium sp. ORS305 and B. liaoningense LMG 18230T. The two fast-growing isolates were related to Rhizobium sp. 8211, R. miluonense CCBAU 41251T, R. miluonense CC-B-L1, Rhizobium sp. CCBAU 51330 and Rhizobium sp. 43015...

Mots clés : Millettia pinnata Pongamia Oil content Fatty acid composition Genetic diversity Salinity tolerance Rhizobia Housekeeping genes Pollination Honey bee Pollen viability 16S rRNA gene

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Page publiée le 23 janvier 2015, mise à jour le 22 mai 2017