Abstract
Change in leaf form or shape has often been enumerated as a potential means of reducing transpiration by plants experiencing water deficit. Because leaf rolling is the first and foremost visible physiological response to water deficit in rice plant, its dynamic nature and impact on leaf water homeostasis and water conservation were studied in hybrid rice (Oryza sativa L.) in depth. Marked diurnal fluctuations were observed in leaf rolling behavior over short as well as extended periods of time during the drying cycle. Leaves were found unrolled (open) during early and late hours of the day in watered plants, whereas stressed plants exhibited partial rolling (score >3) even in the morning, followed by complete rolling at noon (score 5). The rolling of leaves of watered plants fluctuated within a very narrow range (between score 1 to 2) throughout 20 days of drying cycle, whereas stressed plants, although they did not differ from control plants during the first 5 days of stress, displayed wide fluctuations thereafter, culminating into complete rolling (score 5) with no further diurnal variations in space and time. The pattern of changes in leaf water potential closely followed leaf rolling behavior. Examination of leaves by naked eye and hand lens revealed two distinct textures of surfaces in a given leaf blade, i.e. smooth or ridged, located opposite to each other on either side of the midrib. Quite often, the ridged portion rolled first, followed by the smooth one rolling over the former during the drying cycle as the water potential of the ridged portion was less by 0.48 MPa than the smooth portion at the completion of leaf rolling (score 5). Similarly, the water potential of the apical half portion of the leaf blade was less by 0.41 MPa in comparison with the basal half. In the main, two types of leaf rolling were observed: one was classified as acropetal, which consisted of helical and non-helical rolling, and the other was non-acropetal, characterized by either the ridged portion bending first or ridged and smooth portions bending almost simultaneously. Leaf rolling in etiolated leaves was quicker by 14 min than the green ones; however, darkness delayed the rolling (score 5) of green leaves by 32 min. The rate of transpiration decreased by 52% in manually rolled, excised turgid leaves, which reversed back to the initial rate of water loss once the leaves were unrolled (open). In the absence of water supply to the excised leaves, the spontaneously rolled leaves exhibited 87% water saving (only 13% loss in fresh weight) against 68% saving (32% loss) by leaves mechanically prevented from rolling, suggesting its important role in leaf water homeostasis and water economy during limited-water supply conditions. The findings carry biotechnological applications that may further provide important information for the design of strategies for future engineering of an improved external plant defense system against drought with increased water-use-efficiency in hybrid and super hybrid rice.
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Claims 15
Claim · model-written summary
Leaf rolling fluctuated diurnally during drying.
- Taxon
- Hybrid Rice
Oryza sativat0 - Organ / stage
- leafe0
- Outcome
- diurnal fluctuationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Hybrid Rice”
e0“Marked diurnal fluctuations were observed in leaf rolling behavior over short as well as extended periods of time during the drying cycle”
Claim · model-written summary
Stressed plants rolled partially in the morning and completely at noon.
- Taxon
- Hybrid RiceOryza sativat0
- Treatment
- stressed plantse0
- Outcome
- partial rollinge0
- Value
- score >3e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Hybrid Rice”
e0“stressed plants exhibited partial rolling (score >3) even in the morning, followed by complete rolling at noon (score 5)”
Claim · model-written summary
Stressed plants showed complete rolling at noon.
- Taxon
- Hybrid RiceOryza sativat0
- Outcome
- complete rollinge0
- Value
- score 5e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Hybrid Rice”
e0“followed by complete rolling at noon (score 5)”
Claim · model-written summary
Watered leaves remained within rolling scores 1 to 2 over 20 days.
- Taxon
- Hybrid RiceOryza sativat0
- Treatment
- watered plantse0
- Outcome
- rolling of leavese0
- Value
- score 1 to 2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Hybrid Rice”
e0“The rolling of leaves of watered plants fluctuated within a very narrow range (between score 1 to 2) throughout 20 days of drying cycle”
Claim · model-written summary
Stressed leaves developed wide rolling fluctuations after five days and eventually remained completely rolled.
- Taxon
- Hybrid RiceOryza sativat0
- Treatment
- stressed plantse0
- Outcome
- wide fluctuationse0
- Value
- score 5e0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Hybrid Rice”
e0“stressed plants, although they did not differ from control plants during the first 5 days of stress, displayed wide fluctuations thereafter, culminating into complete rolling (score 5) with no further diurnal variations in space and time”
Claim · model-written summary
Leaf water potential tracked leaf rolling.
- Taxon
- Hybrid RiceOryza sativat0
- Organ / stage
- leafe0
- Outcome
- leaf water potentiale0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Hybrid Rice”
e0“The pattern of changes in leaf water potential closely followed leaf rolling behavior”
Claim · model-written summary
Leaf blades had smooth and ridged surfaces on opposite sides of the midrib.
- Taxon
- Hybrid RiceOryza sativat0
- Organ / stage
- leaf bladee0
- Outcome
- smooth or ridgede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Hybrid Rice”
e0“two distinct textures of surfaces in a given leaf blade, i.e. smooth or ridged, located opposite to each other on either side of the midrib”
Claim · model-written summary
The ridged portion often rolled before the smooth portion.
- Taxon
- Hybrid RiceOryza sativat0
- Outcome
- ridged portion rolled firste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Hybrid Rice”
e0“the ridged portion rolled first, followed by the smooth one rolling over the former during the drying cycle”
Claim · model-written summary
The ridged portion had 0.48 MPa lower water potential than the smooth portion at complete rolling.
- Taxon
- Hybrid RiceOryza sativat0
- Organ / stage
- ridged portione0
- Outcome
- water potentiale0
- Direction
- lesse0
- Value
- 0.48 MPae0
- Comparator
- smooth portione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Hybrid Rice”
e0“water potential of the ridged portion was less by 0.48 MPa than the smooth portion at the completion of leaf rolling (score 5)”
Claim · model-written summary
The apical half had 0.41 MPa lower water potential than the basal half.
- Taxon
- Hybrid RiceOryza sativat0
- Organ / stage
- apical half portion of the leaf bladee0
- Outcome
- water potentiale0
- Direction
- lesse0
- Value
- 0.41 MPae0
- Comparator
- basal halfe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Hybrid Rice”
e0“water potential of the apical half portion of the leaf blade was less by 0.41 MPa in comparison with the basal half”
Claim · model-written summary
Leaf rolling included acropetal helical and non-helical forms and non-acropetal forms.
- Taxon
- Hybrid RiceOryza sativat0
- Outcome
- two types of leaf rollinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Hybrid Rice”
e0“two types of leaf rolling were observed: one was classified as acropetal, which consisted of helical and non-helical rolling, and the other was non-acropetal”
Claim · model-written summary
Etiolated leaves rolled 14 min quicker than green leaves.
- Taxon
- Hybrid RiceOryza sativat0
- Organ / stage
- etiolated leavese0
- Outcome
- Leaf rollinge0
- Direction
- quickere0
- Value
- 14 mine0
- Comparator
- green onese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Hybrid Rice”
e0“Leaf rolling in etiolated leaves was quicker by 14 min than the green ones”
Claim · model-written summary
Darkness delayed complete rolling of green leaves by 32 min.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Hybrid Rice”
e0“darkness delayed the rolling (score 5) of green leaves by 32 min”
Claim · model-written summary
Manual rolling reduced transpiration by 52%, which returned after unrolling.
- Taxon
- Hybrid RiceOryza sativat0
- Treatment
- manually rollede0
- Outcome
- rate of transpiratione0
- Direction
- decreasede0
- Value
- 52%e0
- Comparator
- unrolled (open)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Hybrid Rice”
e0“The rate of transpiration decreased by 52% in manually rolled, excised turgid leaves, which reversed back to the initial rate of water loss once the leaves were unrolled (open)”
Claim · model-written summary
Spontaneously rolled excised leaves saved 87% water, against 68% when rolling was prevented.
- Taxon
- Hybrid RiceOryza sativat0
- Treatment
- spontaneously rolled leavese0
- Outcome
- water savinge0
- Direction
- savinge0
- Value
- 87%e0
- Qualifier
- 68% saving (32% loss)e0
- Comparator
- leaves mechanically prevented from rollinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Hybrid Rice”
e0“spontaneously rolled leaves exhibited 87% water saving (only 13% loss in fresh weight) against 68% saving (32% loss) by leaves mechanically prevented from rolling”