Title: Predicting the establishment and spread of Siam weed in Australia: A test of abiotic cues on seed dormancy and germination

Abstract: Significant infestations of Chromolaena odorata are present in the Alice river basin of Townsville and South Johnstone area of Queensland in the north of Australia. This study was undertaken to predict the spread of C. odorata by assessing the impact of abiotic cues on dormancy and germination trends. Seeds from wet tropics infestations in a primary and a secondary forest in Australia were germinated in 1.5x0.9 cm deep petri dishes in an incubator at mean temperature 30°C. Petri dishes containing 50 seeds each were set in a Randomized Complete Block Design of 4 treatments and 3 replications. The empirical trajectory of seed dormancy and germination response of C. odorata to salinity, smoke, acid and alkalines were investigated. Smoked seeds germinated significantly (p<0.0001) higher in water than in soil. The percentage seed germination in smoke treatment was significantly (p<0.001) higher than in non-smoke conditions. Germination rate in both primary and secondary forests was relatively high at low sodium chloride (NaCl) concentration (0.02, 0.04, 0.06 and 0.08 mol L-1). Seeds from populations in primary forests responded more to salinity than seeds sourced from secondary forests. Alkaline solutions (1 M KOH and 1 M NaOH) significantly reduced seed emergence. This study should provide a useful reference tool to effectively predict the trajectory of C. odorata infestations in tropical landscapes. [J.C. Djietror, M. Ohara and C. Appiah (2011). Predicting the establishment and spread of Siam weed in Australia: A test of abiotic cues on seed dormancy and germination. Research Journal of Forestry, 5(3), 115-127, DOI: 10.3923/rjf.2011.115.127]

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Article: WeedsNews2747 (permalink)
Categories: :WeedsNews:research alert, :WeedsNews:forestry, :WeedsNews:seed dispersal, :WeedsNews:seed viability
Date: 12 January 2012; 4:41:57 pm Australian Eastern Daylight Time

Author Name: David Low
Author ID: adminDavid