COMBINED EFFECT OF NITROGEN FERTILIZATION AND PLANT GROWTH-PROMOTING BACTERIA ON GROWTH AND NITROGEN UTILIZATION BY LETTUCE PLANTS

P. Flores, P. Hellín, A. López , J. Fenoll
The effect of Azospirillum + Pantoea on plant growth and the contribution of biological nitrogen fixation (BNF) by Azospirillum to the plant N budget were studied in lettuce grown at different N levels. Plants (Lactuca sativa L. ‘Little Gem Ferro’) were grown in a growth chamber (25/15°C for a 16/8 h light/dark cycle and relative humidity of 60/80%) and treated with Biopron® (15 g containing 109 CFU•g-1 Azospirillum brasilense and Pantoea dispersa), and then irrigated at four different N levels (0, 1, 3 and 7 mM NO3-). Bacteria application increased shoot weight, the shoot/root ratio, plant N concentration and N uptake, regardless of N treatment. The effect of bacteria application on root development was dependent on N application. The assimilation of fixed N was estimated, using the 15N natural abundance method, from the difference in δ15N values between bacteria-treated plants and non-treated plants for each NO3- level. Significant transfer of nitrogen from BNF to the plant by Azospirillum was observed. The extent of the contribution of BNF to the plant N budget depended on the additional NO3- supply. The results showed that bacteria have a potential to supply a considerable amount of N to lettuce plants, as well as to stimulate plant growth.
Flores, P., Hellín, P., López , A. and Fenoll, J. (2012). COMBINED EFFECT OF NITROGEN FERTILIZATION AND PLANT GROWTH-PROMOTING BACTERIA ON GROWTH AND NITROGEN UTILIZATION BY LETTUCE PLANTS. Acta Hortic. 936, 335-340
DOI: 10.17660/ActaHortic.2012.936.43
https://doi.org/10.17660/ActaHortic.2012.936.43
Azospirillum, PGPB, nitrate, biological nitrogen fixation, 15N natural abundance
English

Acta Horticulturae