Abstract
Drought stress triggers mature leaf senescence, which supports plant survival and remobilization of nutrients; yet leaf senescence also critically decreases post-drought crop yield. Drought generally results in carbon/nitrogen imbalance, which is reflected in the increased carbon:nitrogen (C:N) ratio in mature leaves, and which has been shown to be involved in inducing leaf senescence under normal growth conditions. Yet the involvement of the carbon/nitrogen balance in regulation of drought-induced leaf senescence is unclear. To investigate the role of carbon/nitrogen balance in drought-induced senescence, sorghum seedlings were subjected to a gradual soil drought treatment. Leaf senescence symptoms and the C:N ratio, which was indicated by the ratio of non-structural carbohydrate to total N content, were monitored during drought progression. In this study, leaf senescence developed about 12 days after the start of drought treatment, as indicated by various senescence symptoms including decreasing photosynthesis, photosystem II photochemistry efficiency (Fv/Fm) and chlorophyll content, and by the differential expression of senescence marker genes. The C:N ratio was significantly enhanced 10 to 12 days into drought treatment. Leaf senescence occurred in the older (lower) leaves, which had higher C:N ratios, but not in the younger (upper) leaves, which had lower C:N ratios. In addition, a detached leaf assay was conducted to investigate the effect of carbon/nitrogen availability on drought-induced senescence. Exogenous application of excess sugar combined with limited nitrogen promoted drought-induced leaf senescence. Thus our results suggest that the carbon/nitrogen balance may be involved in the regulation of drought-induced leaf senescence.
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Claims 8
Claim · model-written summary
Leaf senescence developed about 12 days after drought treatment started.
- Taxon
- Sorghum bicolor
Sorghum bicolort0 - Treatment
- drought treatmente0
- Outcome
- leaf senescencee0
- Value
- about 12 dayse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“leaf senescence developed about 12 days after the start of drought treatment”
t0“Sorghum bicolor”
Claim · model-written summary
Drought-associated senescence involved decreasing photosynthesis, Fv/Fm and chlorophyll content.
- Taxon
- Sorghum bicolorSorghum bicolort0
- Treatment
- drought treatmente0
- Outcome
- photosynthesis, photosystem II photochemistry efficiency (Fv/Fm) and chlorophyll contente0
- Direction
- decreasinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“after the start of drought treatment, as indicated by various senescence symptoms including decreasing photosynthesis, photosystem II photochemistry efficiency (Fv/Fm) and chlorophyll content”
t0“Sorghum bicolor”
Claim · model-written summary
Senescence marker genes showed differential expression during drought-associated senescence.
- Taxon
- Sorghum bicolorSorghum bicolort0
- Gene
- senescence marker genese0
- Outcome
- differential expressione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the differential expression of senescence marker genes”
t0“Sorghum bicolor”
Claim · model-written summary
The C:N ratio was significantly enhanced 10 to 12 days into drought treatment.
- Taxon
- Sorghum bicolorSorghum bicolort0
- Treatment
- drought treatmente0
- Outcome
- C:N ratioe0
- Direction
- enhancede0
- Qualifier
- 10 to 12 dayse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The C:N ratio was significantly enhanced 10 to 12 days into drought treatment”
t0“Sorghum bicolor”
Claim · model-written summary
Older lower leaves senesced and had higher C:N ratios.
- Taxon
- Sorghum bicolorSorghum bicolort0
- Organ / stage
- older (lower) leavese0
- Outcome
- Leaf senescencee0
- Qualifier
- higher C:N ratiose0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf senescence occurred in the older (lower) leaves, which had higher C:N ratios, but not in the younger (upper) leaves, which had lower C:N ratios”
t0“Sorghum bicolor”
Claim · model-written summary
Younger upper leaves did not senesce and had lower C:N ratios.
- Taxon
- Sorghum bicolorSorghum bicolort0
- Organ / stage
- younger (upper) leavese0
- Outcome
- Leaf senescencee0
- Qualifier
- lower C:N ratiose0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf senescence occurred in the older (lower) leaves, which had higher C:N ratios, but not in the younger (upper) leaves, which had lower C:N ratios”
t0“Sorghum bicolor”
Claim · model-written summary
Excess sugar with limited nitrogen promoted drought-induced leaf senescence.
- Taxon
- Sorghum bicolorSorghum bicolort0
- Treatment
- Exogenous application of excess sugar combined with limited nitrogene0
- Outcome
- drought-induced leaf senescencee0
- Direction
- promotede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenous application of excess sugar combined with limited nitrogen promoted drought-induced leaf senescence”
t0“Sorghum bicolor”
Claim · model-written summary
Carbon/nitrogen balance may regulate drought-induced leaf senescence.
- Taxon
- Sorghum bicolorSorghum bicolort0
- Outcome
- drought-induced leaf senescencee0
- Qualifier
- carbon/nitrogen balancee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the carbon/nitrogen balance may be involved in the regulation of drought-induced leaf senescence”
t0“Sorghum bicolor”
The same questions in other papers
drought · physiology: photosynthesis · Sorghum bicolor (sorghum)Results differ
12 papers in the same direction as this paper · 2 in the opposite direction
- negative
- positive
- positive
11 papers more in this group
See all 15 papers →nitrogen · quality: postharvest · Sorghum bicolor (sorghum)Results agree
1 paper in the same direction as this paper
- negative
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.