Abstract
Humic acids (HAs) have positive effects on plant physiology, but the molecular mechanisms underlying these events are only partially understood. The induction of root growth and emission of lateral roots (LRs) promoted by exogenous auxin is a natural phenomenon. Exogenous auxins are also associated with HA. Gas nitric oxide (NO) is a secondary messenger produced endogenously in plants. It is associated with metabolic events dependent on auxin. With the application of auxin, NO production is significantly increased, resulting in positive effects on plant physiology. Thus it is possible to evaluate the beneficial effects of the application of HA as an effect of auxin. To investigate the effects of HA the parameters of root growth, Zea mays was studied by evaluating the application of 3 mM C L⁻¹ of HA extracted from Oxisol and 100 µM SNP (sodium nitroprusside) and the NO donor, subject to two N-NO₃⁻, high dose (5.0 mM N-NO₃⁻) and low dose (5.0 mM N-NO₃⁻). Treatments with HA and NO were positively increased, regardless of the N-NO₃⁻ taken, as assessed by fresh weight and dry root, issue of LRs. The effects were more pronounced in the treatment with a lower dose of N-NO₃⁻. Detection of reactive oxygen species (ROS) in vivo and catalase activity were evaluated; these tests were associated with root growth. Under application of the bioactive substances tested, detection of ROS and catalase activity increased, especially in treatments with lower doses of N-NO₃⁻. The results of this experiment indicate that the effects of HA are dependent on ROS generation, which act as a messenger that induces root growth and the emission of LRs.
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Claims 8
Claim · model-written summary
Humic acid increased root fresh weight and dry weight under nitrate treatments.
Zea maysNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatments with HA and NO were positively increased, regardless of the N-NO₃⁻ taken, as assessed by fresh weight and dry root, issue of LRs.”
t0“Zea mays”
Claim · model-written summary
Nitric oxide treatment increased root fresh weight and dry weight under nitrate treatments.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatments with HA and NO were positively increased, regardless of the N-NO₃⁻ taken, as assessed by fresh weight and dry root, issue of LRs.”
t0“Zea mays”
Claim · model-written summary
Humic acid increased lateral-root emergence.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatments with HA and NO were positively increased, regardless of the N-NO₃⁻ taken, as assessed by fresh weight and dry root, issue of LRs.”
t0“Zea mays”
Claim · model-written summary
Nitric oxide increased lateral-root emergence.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treatments with HA and NO were positively increased, regardless of the N-NO₃⁻ taken, as assessed by fresh weight and dry root, issue of LRs.”
t0“Zea mays”
Claim · model-written summary
The root-growth effects were more pronounced under the lower nitrate dose.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The effects were more pronounced in the treatment with a lower dose of N-NO₃⁻.”
t0“Zea mays”
Claim · model-written summary
Bioactive substance treatment increased reactive oxygen species detection, especially at lower nitrate doses.
- Treatment
- bioactive substances testede0
- Outcome
- detection of ROSe0
- Direction
- increasede0
- Qualifier
- lower doses of N-NO₃⁻e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under application of the bioactive substances tested, detection of ROS and catalase activity increased, especially in treatments with lower doses of N-NO₃⁻.”
t0“Zea mays”
Claim · model-written summary
Bioactive substance treatment increased catalase activity, especially at lower nitrate doses.
- Treatment
- bioactive substances testede0
- Outcome
- catalase activitye0
- Direction
- increasede0
- Qualifier
- lower doses of N-NO₃⁻e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Under application of the bioactive substances tested, detection of ROS and catalase activity increased, especially in treatments with lower doses of N-NO₃⁻.”
t0“Zea mays”
Claim · model-written summary
The authors attributed humic-acid-induced root growth and lateral-root emergence to ROS generation.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the effects of HA are dependent on ROS generation, which act as a messenger that induces root growth and the emission of LRs.”
t0“Zea mays”
The same questions in other papers
nitric oxide · growth · Zea mays (maize)Positive and negative results
7 papers in the same direction as this paper · 5 in the opposite direction
- negative
- no effect
- negative
9 papers more in this group
See all 13 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.