Saprophytic and pathogenic behaviour of R. solani AG2-1 (ZG-5) in a soil amended with Diplotaxis tenuifolia or Brassica nigra manures and incubated at different temperatures and soil water content |
| |
Authors: | Titiek Yulianti K Sivasithamparam David W Turner |
| |
Institution: | (1) School of Earth and Geographical Sciences, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia;(2) School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia;(3) Present address: Research Institute for Tobacco and Fibre Crops, Jl. Raya Karangplosa, Malang, East Java, Indonesia |
| |
Abstract: | The Brassicaceae species Diplotaxis tenuifolia and Brassica nigra contain high concentrations of glucosinolates, the precursors of isothiocyanates (ITCs) that can have biofumigation effects
in amended soils. In a laboratory experiment, incorporation of these plants as green manures into soil was expected to suppress
Rhizoctonia solani AG2-1 (ZG5), the causal agent of damping-off in canola (Brassica napus). The manures were incorporated at 1 (1% w/w) or 5 (5% w/w) g fresh material per 100 g dry soil and incubated for 6 months
at 10, 20, or 30°C and at soil water contents of 10%, 40%, or 70% of water holding capacity. R. solani survived for up to 6 months as a saprophyte in un-amended soil at all soil water contents and at 10 and 20°C. A temperature
of 30°C suppressed R. solani below the level of detection in all treatments after one week. At 1% concentration, the green manures increased the colonisation
of the soil by R. solani, which caused severe damping-off of canola subsequently sown in this soil treatment. Soil amendments at 1% temporarily increased
soil microbial activity. The addition of B. nigra or D. tenuifolia green manure at 5% concentration suppressed the saprophytic growth of R. solani incubated at 10 or 20°C over all soil water contents and significantly increased the microbial activity at all soil temperatures
and water contents. Canola sown into these pots did not succumb to damping-off. The efficiency of hydrolysis of glucosinolates
in the 5% treatment in the first week of incubation ranged from 1.6% for 2-propenyl ITC, extracted from soil containing tissues
of B. nigra, to 3.4% for 3-butenyl ITC extracted from soil containing tissues of D. tenuifolia. 2-propenyl ITC could not be detected after 7 d of incubation. In the longer term (weeks to months), the increase of microbial
activity, caused by adding green manures at 5%, or volatiles from the green manures, most likely played a dominant role in
suppressing R. solani. The impact of ITCs, if any, appears to be short-term (days).
Responsible Editor: Peter A. H. Bakker |
| |
Keywords: | Biofumigation Brassicaceae Canola Green manures Isothiocyanates Microbial activity |
本文献已被 SpringerLink 等数据库收录! |
|