Abstract
Abstract Background Drought is a major determinant for growth and productivity of all crops, including cereals, and the drought-induced detrimental effects are anticipated to jeopardize world food security under the ongoing global warming scenario. Biostimulants such as humic acid (HA) can improve drought tolerance in many cereals, including maize and sorghum. These two plant species are genetically related; however, maize is more susceptible to drought than sorghum. The physiological and biochemical mechanisms underlying such differential responses to water shortage in the absence and presence of HA, particularly under field conditions, are not fully understood. Results Herein, the effects of priming maize and sorghum seeds in 100 mg L −1 HA on their vegetative growth and physiological responses under increased levels of drought (100%, 80%, and 60% field capacity) were simultaneously monitored in the field. In the absence of HA, drought caused 37.0 and 58.7% reductions in biomass accumulation in maize compared to 21.2 and 32.3% in sorghum under low and high drought levels, respectively. These responses were associated with differential retardation in overall growth, relative water content (RWC), photosynthetic pigments and CO 2 assimilation in both plants. In contrast, drought increased root traits as well as H 2 O 2 , malondialdehyde, and electrolyte leakage in both species. HA treatment significantly improved the growth of both plant species under well-watered and drought conditions, with maize being more responsive than sorghum. HA induced a 29.2% increase in the photosynthetic assimilation rate in maize compared to 15.0% in sorghum under high drought level. The HA-promotive effects were also associated with higher total chlorophyll, stomatal conductance, RWC, sucrose, total soluble sugars, total carbohydrates, proline, and total soluble proteins. HA also reduced the drought-induced oxidative stress via induction of non-enzymic and enzymic antioxidants at significantly different extents in maize and sorghum. Conclusion The current results identify significant quantitative differences in a set of critical physiological biomarkers underlying the differential responses of field-grown maize and sorghum plants against drought. They also reveal the potential of HA priming as a drought-alleviating biostimulant and as an effective approach for sustainable maize and sorghum production and possibly other crops in drought-affected lands.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 17
Claim · model-written summary
Drought reduced maize biomass accumulation by 37.0% at the low drought level.
Zea maysNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“drought caused 37.0 and 58.7% reductions in biomass accumulation in maize compared to 21.2 and 32.3% in sorghum under low and high drought levels, respectively”
Claim · model-written summary
Drought reduced maize biomass accumulation by 58.7% at the high drought level.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“drought caused 37.0 and 58.7% reductions in biomass accumulation in maize compared to 21.2 and 32.3% in sorghum under low and high drought levels, respectively”
Claim · model-written summary
Drought reduced sorghum biomass accumulation by 21.2% at the low drought level.
SorghumNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“drought caused 37.0 and 58.7% reductions in biomass accumulation in maize compared to 21.2 and 32.3% in sorghum under low and high drought levels, respectively”
Claim · model-written summary
Drought reduced sorghum biomass accumulation by 32.3% at the high drought level.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“drought caused 37.0 and 58.7% reductions in biomass accumulation in maize compared to 21.2 and 32.3% in sorghum under low and high drought levels, respectively”
Claim · model-written summary
Drought was associated with retarded overall growth, relative water content and photosynthetic pigments in maize and sorghum.
- Treatment
- drought stresst1
- Outcome
- overall growth, relative water content (RWC), photosynthetic pigmentse1
- Direction
- retardatione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“maize and sorghum”
t1“drought stress”
e1“These responses were associated with differential retardation in overall growth, relative water content (RWC), photosynthetic pigments and CO 2 assimilation in both plants”
Claim · model-written summary
Drought was associated with retarded CO2 assimilation in maize and sorghum.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“maize and sorghum”
t1“drought stress”
e1“These responses were associated with differential retardation in overall growth, relative water content (RWC), photosynthetic pigments and CO 2 assimilation in both plants”
Claim · model-written summary
Drought increased root traits in maize and sorghum.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“maize and sorghum”
e1“In contrast, drought increased root traits as well as H 2 O 2 , malondialdehyde, and electrolyte leakage in both species”
Claim · model-written summary
Drought increased H2O2, malondialdehyde and electrolyte leakage in maize and sorghum.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“maize and sorghum”
e1“In contrast, drought increased root traits as well as H 2 O 2 , malondialdehyde, and electrolyte leakage in both species”
Claim · model-written summary
HA significantly improved the growth of maize and sorghum under well-watered and drought conditions compared with no HA.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“maize and sorghum”
e1“HA treatment significantly improved the growth of both plant species under well-watered and drought conditions, with maize being more responsive than sorghum”
e2“In the absence of HA”
Claim · model-written summary
HA increased growth more strongly in maize than in sorghum.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“HA treatment significantly improved the growth of both plant species under well-watered and drought conditions, with maize being more responsive than sorghum”
Claim · model-written summary
HA increased photosynthetic assimilation rate by 29.2% in maize under high drought.
- Treatment
- HAe1
- Outcome
- photosynthetic assimilation ratee1
- Direction
- increasee1
- Value
- 29.2%e1
- Qualifier
- under high drought levele1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“HA induced a 29.2% increase in the photosynthetic assimilation rate in maize compared to 15.0% in sorghum under high drought level”
Claim · model-written summary
HA increased photosynthetic assimilation rate by 15.0% in sorghum under high drought.
- Treatment
- HAe1
- Outcome
- photosynthetic assimilation ratee1
- Direction
- increasee1
- Value
- 15.0%e1
- Qualifier
- under high drought levele1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“HA induced a 29.2% increase in the photosynthetic assimilation rate in maize compared to 15.0% in sorghum under high drought level”
Claim · model-written summary
HA-promotive effects were associated with higher total chlorophyll, stomatal conductance and RWC in maize and sorghum.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“maize and sorghum”
e1“The HA-promotive effects were also associated with higher total chlorophyll, stomatal conductance, RWC, sucrose, total soluble sugars, total carbohydrates, proline, and total soluble proteins”
Claim · model-written summary
HA-promotive effects were associated with higher sucrose, total soluble sugars and total carbohydrates in maize and sorghum.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“maize and sorghum”
e1“The HA-promotive effects were also associated with higher total chlorophyll, stomatal conductance, RWC, sucrose, total soluble sugars, total carbohydrates, proline, and total soluble proteins”
Claim · model-written summary
HA-promotive effects were associated with higher proline and total soluble proteins in maize and sorghum.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“maize and sorghum”
e1“The HA-promotive effects were also associated with higher total chlorophyll, stomatal conductance, RWC, sucrose, total soluble sugars, total carbohydrates, proline, and total soluble proteins”
Claim · model-written summary
HA reduced drought-induced oxidative stress in maize and sorghum via induction of antioxidants, to significantly different extents.
- Treatment
- HAe1
- Outcome
- drought-induced oxidative stresse1
- Direction
- reducede1
- Qualifier
- via induction of non-enzymic and enzymic antioxidantse1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“HA also reduced the drought-induced oxidative stress via induction of non-enzymic and enzymic antioxidants at significantly different extents in maize and sorghum”
Claim · model-written summary
HA priming is a potential drought-alleviating biostimulant for sustainable maize and sorghum production.
- Outcome
- drought-alleviating biostimulante1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“They also reveal the potential of HA priming as a drought-alleviating biostimulant and as an effective approach for sustainable maize and sorghum production”
The same questions in other papers
drought · growth · SorghumResults differ
58 papers in the same direction as this paper · 14 in the opposite direction
- negative
- negative
- positive
69 papers more in this group
See all 73 papers →other · physiology: photosynthesis · SorghumPositive and negative results
1 in the opposite direction
- no effect
other · physiology: oxidative · SorghumPositive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
drought · physiology: oxidative · SorghumPositive and negative results
5 papers in the same direction as this paper · 1 in the opposite direction
- negative
- positive
- no effect
3 papers more in this group
See all 7 papers →other · growth · SorghumPositive and negative results
9 papers in the same direction as this paper · 1 in the opposite direction
- negative
- positive
- positive
7 papers more in this group
See all 11 papers →drought · physiology: oxidative · Zea mays (maize)Positive and negative results
87 papers in the same direction as this paper · 8 in the opposite direction
- negative
- negative
- negative
92 papers more in this group
See all 96 papers →other · growth · Zea mays (maize)Positive and negative results
163 papers in the same direction as this paper · 20 in the opposite direction
- negative
- no effect
- no effect
180 papers more in this group
See all 184 papers →drought · growth · Zea mays (maize)Positive and negative results
307 papers in the same direction as this paper · 77 in the opposite direction
- positive
- negative
- negative
381 papers more in this group
See all 385 papers →8 of 10 groups shown: named compounds and organisms first, then groups whose results differ (checked claim by claim), then those with positive and negative results, then the smaller groups.
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.