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Summary Steady‐state photosyntheticCO2responses (A/Cicurves) are used to assess environmental responses of photosynthetic traits and to predict future vegetative carbon uptake through modeling. The recent development of rapidA/Cicurves (RACiRs) permits faster assessment of these traits by continuously changing [CO2] around the leaf, and may reveal additional photosynthetic properties beyond what is practical or possible with steady‐state methods.Gas exchange necessarily incorporates photosynthesis and (photo)respiration. Each process was expected to respond on different timescales due to differences in metabolite compartmentation, biochemistry and diffusive pathways. We hypothesized that metabolic lags in photorespiration relative to photosynthesis/respiration andCO2diffusional limitations can be detected by varying the rate of change in [CO2] duringRACiR assays. We tested these hypotheses through modeling and experiments at ambient and 2% oxygen.Our data show that photorespiratory delays cause offsets in predictedCO2compensation points that are dependent on the rate of change in [CO2]. Diffusional limitations may reduce the rate of change in chloroplastic [CO2], causing a reduction in apparentRACiR slopes under highCO2ramp rates.MultirateRACiRs may prove useful in assessing diffusional limitations to gas exchange and photorespiratory rates.
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The role of the 5′ HoxA genes in the development of the hindgut, vent, and a novel sphincter in a derived teleost (bluebanded goby, Lythrypnus dalli )
Abstract Unique expression patterns of the 5′ HoxA genes are associated with the evolution and development of novel features including claspers in cartilaginous fishes, modified pectoral fins in batoids, and the yolk sac extension in Cypriniformes. Here, we demonstrate a role forHoxA11aandHoxA13ain demarcating the hindgut in fishes of the family Gobiidae, including a novel sphincter called the intestinal rectal sphincter (IRS). Disruption of 5′ HoxA expression, via manipulation of retinoic acid signaling, results in failure of the IRS and/or vent to develop. Furthermore, exposure to HoxA disruptors alters 5′ HoxA expression, in association with developmental phenotypes, demonstrating a functional link between 5′ HoxA expression and development of a novel feature in the bluebanded goby,Lythrypnus dalli.
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- Award ID(s):
- 1656487
- PAR ID:
- 10182860
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Experimental Zoology Part B: Molecular and Developmental Evolution
- Volume:
- 340
- Issue:
- 8
- ISSN:
- 1552-5007
- Format(s):
- Medium: X Size: p. 518-530
- Size(s):
- p. 518-530
- Sponsoring Org:
- National Science Foundation
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