Journal
ANNALS OF APPLIED BIOLOGY
Volume 159, Issue 2, Pages 202-211Publisher
WILEY
DOI: 10.1111/j.1744-7348.2011.00487.x
Keywords
Humic matter; humic substances; physiological activity; structural-activity ratio; vermicompost
Categories
Funding
- CNPq
- INCT
- FAPERJ
- IFS
Ask authors/readers for more resources
We progressively reduced the complexity of humic matter by a mild sequential removal of unbound or free components, weakly, and strongly bound molecules. The auxin-like response of residues from each step was tested using tomato (cv. Micro-Tom) seedlings expressing DR5 auxin synthetic promoter fused to the beta-glucuronidase (GUS) reporter gene and the low auxin-sensitivity diageotropica (dgt) mutant. Both exogenous auxin and humic matter promoted lateral root emergence in the control, but failed to induce lateral roots in the dgt mutant. When strongly bound components were removed from humic matter by breaking the ester and ether bonds, the humic residues lost their ability to induce the DR5::GUS activity and lateral root emergence. However, these capacities were retained in the free or weakly bound molecules. These findings confirm that auxin-like activity in humic matter is associated with complex hydrophobic structures, whose simplification by hydrolysis may release auxin-like molecules.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available