Abstract
Abstract The construction of the Three Gorges–Gezhouba Dam cascade hydropower station has changed the water level fluctuation pattern of the habitats for remnant rare and endangered Myricaria laxiflora populations downstream of the dam. The present study utilized biochemical markers of photosynthetic physiology to evaluate the spatiotemporal responses of remnant populations to human-regulated water level fluctuations. The results showed that the photosynthetic physiological activities of remnant M. laxiflora populations underwent a period of rapid growth, followed by a gradual decline in the growth recovery phase after flooding. During the entire experimental period, photosynthetic physiological activities of remnant M. laxiflora populations changed with prolongation of emergence time: specifically, net photosynthetic rate and stomatal conductance initially decreased and then subsequently increased, intercellular carbon dioxide concentrations peaked at mid-phase and transpiration rate continuously increased. The maximum net photosynthetic rate, apparent photosynthetic quantum efficiency and dark respiration rate in the light–response curves of the plants continuously increased during growth. The water level gradient also significantly affected the photosynthetic physiological activities in the remnant populations, i.e. the photosynthetic physiological activities of high-altitude plants were significantly higher than the middle- and low-altitude plants. The changes in photosynthetic pigment content of plants in remnant populations during the growth recovery phase and the entire growth period were similar to those occurring in photosynthetic activities in plants. Further, canonical correspondence analysis showed that photosynthetic physiological activities in the plants were significantly correlated with changes in water levels, emergence time, elevation gradient, soil water and soil nitrogen contents. Therefore, the artificial regulation of water level fluctuations by large hydropower stations will inevitably affect the photosynthetic activities and growth of remnant M. laxiflora populations.
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 11
Claim · model-written summary
Photosynthetic activity rose rapidly and then declined during postflood recovery.
- Taxon
- M. laxifloraMyricaria laxiflorae0
- Outcome
- photosynthetic physiological activitiese0
- Direction
- rapid growth, followed by a gradual declinee0
- Qualifier
- growth recovery phase after floodinge0
Verbatim
e0“photosynthetic physiological activities of remnant M. laxiflora populations underwent a period of rapid growth, followed by a gradual decline in the growth recovery phase after flooding.”
Claim · model-written summary
Net photosynthetic rate first fell and then rose with emergence time.
Not reportedTaxonSetting
Verbatim
e0“net photosynthetic rate and stomatal conductance initially decreased and then subsequently increased”
Claim · model-written summary
Stomatal conductance first fell and then rose with emergence time.
Not reportedTaxonSetting
Verbatim
e0“net photosynthetic rate and stomatal conductance initially decreased and then subsequently increased”
Claim · model-written summary
Intercellular carbon dioxide peaked in mid-phase.
Not reportedTaxon
Verbatim
e0“intercellular carbon dioxide concentrations peaked at mid-phase”
Claim · model-written summary
Transpiration rate continuously increased.
Not reportedTaxon
Verbatim
e0“transpiration rate continuously increased”
Claim · model-written summary
Maximum net photosynthetic rate increased during growth.
Not reportedTaxon
Verbatim
e0“The maximum net photosynthetic rate, apparent photosynthetic quantum efficiency and dark respiration rate in the light–response curves of the plants continuously increased during growth.”
Claim · model-written summary
Apparent photosynthetic quantum efficiency increased during growth.
Not reportedTaxon
Verbatim
e0“The maximum net photosynthetic rate, apparent photosynthetic quantum efficiency and dark respiration rate in the light–response curves of the plants continuously increased during growth.”
Claim · model-written summary
Dark respiration rate increased during growth.
Not reportedTaxon
Verbatim
e0“The maximum net photosynthetic rate, apparent photosynthetic quantum efficiency and dark respiration rate in the light–response curves of the plants continuously increased during growth.”
Claim · model-written summary
High-altitude plants had significantly higher photosynthetic activity than middle- and low-altitude plants.
- Outcome
- photosynthetic physiological activitiese0
- Direction
- significantly highere0
- Comparator
- middle- and low-altitude plantse0
- Setting
- high-altitudee0
Not reportedTaxon
Verbatim
e0“the photosynthetic physiological activities of high-altitude plants were significantly higher than the middle- and low-altitude plants.”
Claim · model-written summary
Photosynthetic pigment changes resembled photosynthetic activity changes.
- Outcome
- photosynthetic pigment contente0
- Direction
- similare0
- Qualifier
- growth recovery phase and the entire growth periode0
- Comparator
- photosynthetic activities in plantse0
Not reportedTaxon
Verbatim
e0“The changes in photosynthetic pigment content of plants in remnant populations during the growth recovery phase and the entire growth period were similar to those occurring in photosynthetic activities in plants.”
Claim · model-written summary
Photosynthetic activities were significantly correlated with water levels, emergence time, elevation, soil water and soil nitrogen.
Not reportedTaxonDirection
Verbatim
e0“photosynthetic physiological activities in the plants were significantly correlated with changes in water levels, emergence time, elevation gradient, soil water and soil nitrogen contents.”