A comparison between foliar application and seed inoculation of biofertilizers on canola (Brassica napus L.) grown under waterlogged conditions

摘要

Waterlogging restricts canola growth via different physiological changes. The objective of this work was to compare the effects of the foliar and seed application of two biofertilizers on some physiological and morphological responses in canola plants (Brassica napus L. cv. Hayola 401) under waterlogging stress conditions. Plants at 5-leaf stage were exposed to flooding conditions for two weeks. Two biofertilizers; AAP (Azotobacter chroococcum, Azospirillum spp. and Pseudomonas spp.) and APB (Azospirillum spp., Pseudomonas fluorescens and Basillus subtilis) were applied by seed inoculation or foliar spray at different times i.e. before waterlogging, after waterlogging and, before and after waterlogging. The results showed that the flooding stress significantly decreased the dry weight and length of the shoots and roots. The activity of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX) were reduced, whereas lipid peroxidation and ethylene production in the leaves were increased under waterlogging stress. The adverse effects of the flooding stress were significantly alleviated by the seed inoculation and foliar application once (before the stress) of both biofertilizers compared to the waterlogged control. However, among two methods, inoculating the seeds with the biofertilizers is cost efficient and advisable to alleviate waterlogging damage in canola.