Biodegradation and plant protection from the herbicide 2,4-D by plant-microbial associations in cotton production systems
✍ Scribed by L. Feng; I. R. Kennedy
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 879 KB
- Volume
- 54
- Category
- Article
- ISSN
- 0006-3592
No coin nor oath required. For personal study only.
✦ Synopsis
A significant ''biosafening'' protection of plants synthetic pathways unique to plants. Because crops usufrom the effect of 2,4-D in plant-microbial associations ally share these processes with competing weeds, many has been demonstrated in this study. The 2,4-D-degradherbicides are nonselective. Others can only be used ing plasmid, pJP4 was transferred into Rhizobium sp.
selectively on tolerant crops, mainly as a consequence CB1024, which nodulates Dolichos lablab, and Azospirilof a differential uptake of the chemicals. For example, lum brasilense Sp7 carrying a nifA-lacZ gene marker, which can colonize cotton roots. Both transconjugants studies on atrazine persistence and toxicity in Australian degraded 2,4-D in pure culture via cometabolism up to soils showed that sensitive crops such as the sunflower 50 g mL Ϫ1 . When the transconjugants were inoculated may be damaged when grown in rotation after tolerant onto Dolichos lablab and cotton, respectively, such plants crops, or if irrigated with contaminated water (Bowmer, were resistant to this herbicide when the nutrient solution 1981). Herbicide-induced declines in plant growth and was treated with 2,4-D up to 10 g mL Ϫ1 for Dolichos lablab and 0.5 g mL Ϫ1 for cotton. Plants inoculated with N 2 fixation in legume plants were also reported (Clark wild-type strains were dead (Dolichos lablab) or dying and Mahanty, 1991;Eberbach and Douglas, 1989). Con-(cotton). Because cotton is more sensitive to herbicides, siderable damage to cotton could be caused by 2,4-D only incomplete protection of plants was achieved with residue from previous application or from spray drift the transconjugant. Improving the effect of colonization (Llewllyn et al., 1990).
of Azospirillum on cotton roots may be critical for a complete degradation and plant protection. The transconju-Although application of microorganisms offers great gant of Rhizobium sp. CB1024 was still able to nodulate potential for degradation of particular pesticides, the Dolichos lablab, and N 2 -fixing activity was only slightly results from soil inoculation have been inconsistent, with affected. Other pesticide-degrading capacities may also success as enhanced biodegradation observed only spasbe inserted into those plant-associated bacterial strains modically (Greer and Shelton, 1992). Most successful for the degradation of these chemicals by plant-microbial associations. Whether such systems will be successful studies have been conducted in the laboratory under when applied in the field with competition from other optimal conditions required for the growth or metabobacteria is being examined.