Photosynthesis Gas Exchange System with Internal CO2 Directly Measured

Boyer, John S.; Kawamitsu, Yoshinobu

doi:10.2525/ecb.49.193

Cited by 22 publications

(55 citation statements)

References 25 publications

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“…1). In the cup, the CO2 equilibrated with that in the stomatal pores adjacent to the airspace Lauer and Boyer, 1992;Boyer and Kawamitsu, 2011). The cup was connected in a closed loop with an IRGA (LI-840A; LI-COR) and a micro blower (109P0412H309; Sanyo Denki Co., Ltd., Osaka, Japan) which allows the air to gently circulate around the loop (ca.…”

Section: Plant Materialsmentioning

confidence: 99%

“…The condensate naturally dripped through the inner wall of the condenser to the surface of the water seal and did not affect the measurement. The cup was located opposite the blower in the closed loop so as to prevent bulk air movement through the leaf (Boyer and Kawamitsu, 2011). The approximate total volume of the closed system was 100 ml (including LI-840A) with a total path length of 1.8 m. Leaf temperature was measured with a fine 0.13 mm chromel-constantan thermocouple (CHCO-005; Omega engineering, Stanford, CT, USA) appressed to the underside of the leaf by the flexed stainless wire in the cup (Fig.…”

Section: Plant Materialsmentioning

confidence: 99%

“…Sharkey et al (1982) measured Ci directly along with the standard gas exchange parameters. Later, Boyer and Kawamitsu (2011) incorporated the Ci measurement of Sharkey et al (1982) into a gas exchange system. They experimentally measured the A Ci curve in sunflower, determined the effect of stomatal closure, and confirmed the hindrance of water vapor on entry of CO2.…”

Section: Introductionmentioning

confidence: 99%

“…These are considered problems for the A Ci analysis, which usually depends on calculated Ci and thus the diffusive behavior of water vapor. Lauer and Boyer (1992) and Boyer and Kawamitsu (2011) considered the direct method to be a robust approach for tracing A Ci curves. In this study, we incorporated a direct Ci measurement system into the LI-6400 open gas exchange system (LI-COR, Lincoln, NE, USA).…”

Section: Introductionmentioning

confidence: 99%

“…The applicability of the system for A Ci curve measurement was tested in the sunflower (Helianthus annuus L.) leaf. We took special care to minimize bulk air flow through the leaf (Lauer and Boyer, 1992;Boyer and Kawamitsu, 2011), diffusion leaks (Flexas et al, 2007;Rodeghiero et al, 2007), and changes in the CO2 gradient across the leaf mesophyll (Mott and O'Leary, 1984;Parkhurst et al, 1988;Parkhurst and Mott, 1990) that can be important for the measurement.…”

Section: Introductionmentioning

confidence: 99%

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Tracing Photosynthetic Response Curves with Internal CO<sub>2</sub> Measured Directly

Tominaga

Kawamitsu

2015

Environmental Control in Biology

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In this study, a system to measure leaf internal CO2 (Ci) was incorporated into an open gas exchange system (LI-COR, Lincoln, NE, USA). The Ci was directly measured with a cup attached to the abaxial surface of sunflower (Helianthus annuus L.) leaves with open stomata while normal CO2 and water vapor exchange through the same section of adaxial surface was simultaneously detected. The potential problems in the system, namely bulk air flow through the leaf, diffusion leaks, and change in the CO2 gradient inside the leaf, were examined with the aim to apply the system to measure net photosynthesis at various Ci (i.e. A Ci curves). A micro blower constantly circulated the air in a loop without pressure pulses or bulk air movement through the leaf. The measured Ci (Ci(m)) generally followed the external CO2 as much as the calculated one (Ci(c)). There was close agreement between the Ci(m) and the Ci(c) particularly at low Ci, and the diffusion leak hardly affected the relationship between the two. Despite possible alterations of leaf properties by cup attachment, the direct measurement is expected to cast a new light on leaf gas exchange.

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Section: Plant Materialsmentioning

confidence: 99%

Section: Plant Materialsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Tracing Photosynthetic Response Curves with Internal CO<sub>2</sub> Measured Directly

Tominaga

Kawamitsu

2015

Environmental Control in Biology

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δ¹³C as a tool for iron and phosphorus deficiency prediction in crops

et al. 2023

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Many studies proposed the use of stable carbon isotope ratio (δ13C) as a predictor of abiotic stresses in plants, considering only drought and nitrogen deficiency without further investigating the impact of other nutrient deficiencies, that is, phosphorus (P) and/or iron (Fe) deficiencies. To fill this knowledge gap, we assessed the δ13C of barley (Hordeum vulgare L.), cucumber (Cucumis sativus L.), maize (Zea mays L.), and tomato (Solanum lycopersicon L.) plants suffering from P, Fe, and combined P/Fe deficiencies during a two‐week period using an isotope‐ratio mass spectrometer. Simultaneously, plant physiological status was monitored with an infra‐red gas analyzer. Results show clear contrasting time‐, treatment‐, species‐, and tissue‐specific variations. Furthermore, physiological parameters showed limited correlation with δ13C shifts, highlighting that the plants' δ13C, does not depend solely on photosynthetic carbon isotope fractionation/discrimination (Δ). Hence, the use of δ13C as a predictor is highly discouraged due to its inability to detect and discern different nutrient stresses, especially when combined stresses are present.

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