Nocturnal stomatal conductance and ambient air quality standards for ozone

Musselman, Robert C.; Minnick, Tamera J

doi:10.1016/s1352-2310(99)00355-6

Cited by 116 publications

(70 citation statements)

References 117 publications

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“…The MOD16 ET does not account for disturbance history or species composition and stand age [7,34], which could also add further uncertainty. The algorithm makes the assumption that the stomata close during the night, while studies such as Musselman and Minnick [54] have reported stomata opening during the night. This induces underestimation of daily ET because of the bias imposed by night time vegetation transpiration [34].…”

Section: Discussionmentioning

confidence: 99%

Validation of Global Evapotranspiration Product (MOD16) using Flux Tower Data in the African Savanna, South Africa

et al. 2014

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Globally, water is an important resource required for the survival of human beings. Water is a scarce resource in the semi-arid environments, including South Africa. In South Africa, several studies have quantified evapotranspiration (ET) in different ecosystems at a local scale. Accurate spatially explicit information on ET is rare in the country mainly due to lack of appropriate tools. In recent years, a remote sensing ET product from the MODerate Resolution Imaging Spectrometer (MOD16) has been developed. However, its accuracy is not known in South African ecosystems. The objective of this study was to validate the MOD16 ET product using data from two eddy covariance flux towers, namely; Skukuza and Malopeni installed in a savanna and woodland ecosystem within the Kruger National Park, South Africa. Eight day cumulative ET data from the flux towers was calculated to coincide with the eight day MOD16 products over a period of 10 years from 2000 to 2010. The Skukuza flux tower results showed inconsistent comparisons with MOD16 ET. The Malopeni site achieved a poorer comparison with MOD16 ET compared to the Skukuza, and due to a shorter measurement period, data validation was performed for 2009 only. The inconsistent comparison of MOD16 and flux tower-based ET can be attributed to, among other things, the parameterization of the Penman-Monteith model, flux tower measurement errors, and flux tower footprint vs. OPEN ACCESSRemote Sens. 2014, 6 7407 MODIS pixel. MOD16 is important for global inference of ET, but for use in South Africa's integrated water management, a locally parameterized and improved product should be developed.

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Section: Discussionmentioning

confidence: 99%

Validation of Global Evapotranspiration Product (MOD16) using Flux Tower Data in the African Savanna, South Africa

et al. 2014

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“…However, reports on incomplete stomatal closure exist, although they are scarce for conifers. A discussion on nocturnal g sto , and its toxicological relevance is thoroughly presented in Musselman et al (2000) together with a listing of plants reported to show nocturnal g sto . Scots pine was listed to present nocturnal conductance based only on the inference from Skärby et al (1989).…”

Section: Nocturnal Uptakementioning

confidence: 99%

Foliage surface ozone deposition: a role for surface moisture?

et al. 2006

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Abstract. This paper addresses the potential role of surface wetness in ozone deposition to plant foliage. We studied Scots pine foliage in field conditions at the SMEARII field measurement station in Finland. We used a combination of data from flux measurement at the shoot (enclosure) and canopy scale (eddy covariance), information from foliage surface wetness sensors, and a broad array of ancillary measurements such as radiation, precipitation, temperature, and relative humidity. Environmental conditions were defined as moist during rain or high relative humidity and during the subsequent twelve hours from such events, circumstances that were frequent at this boreal site. From the measured fluxes we estimated the ozone conductance using it as the expression of the strength of ozone removal surface sink or total deposition. Further, we estimated the stomatal contribution and the remaining deposition was interpreted and analysed as the non-stomatal sink.The combined time series of measurements showed that both shoot and canopy-scale ozone total deposition were enhanced when moist conditions occurred. On average, the estimated stomatal deposition accounted for half of the measured removal at the shoot scale and one third at the canopy scale. However, during dry conditions the estimated stomatal uptake predicted the behaviour of the measured deposition, but during moist conditions there was disagreement. The estimated non-stomatal sink was analysed against several environmental factors and the clearest connection was found with ambient relative humidity. The relationship disappeared under 70% relative humidity, a threshold that coincides with the value at which surface moisture gathers at the foliage surface according to the leaf surface wetness measurements. This suggests the non-stomatal ozone sink on the foliage to be modulated by the surface films. We attempted to extract such potential modulation with the estimated film formation viaCorrespondence to: N. Altimir (nuria.altimir@helsinki.fi) the theoretical expression of adsorption. Whereas this procedure could predict the behaviour of the non-stomatal sink, it implied a chemical sink that was not accountable as simple ozone decomposition. We discuss the existence of other mechanisms whose relevance in the removal of ozone needs to be clarified, in particular: a significant nocturnal stomatal aperture neglected in the estimations, and a potentially large chemical sink offered by reactive biogenic organic volatile compounds.

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“…Inherent LMA may thus be roughly related to sensitivity to O 3 stress (Bussotti, 2008;Zhang et al, 2012). Also Musselman and Minnick (2000) suggested that plant tolerance to O 3 stress may depend on its photosynthetic capacity because detoxification and repair require energy (Noctor and Foyer, 1998). The sensitivity to foliar O 3 injury may thus be explained by the ratio of stomatal O 3 flux to net photosynthesis (Fredericksen et al, 1996;Kolb and Matyssek, 2001), indicating a balance between O 3 exposure of mesophyll cells and availability of photosynthates for repair or detoxification.…”

Section: Introductionmentioning

confidence: 99%

Determinants of stomatal sluggishness in ozone-exposed deciduous tree species

Hoshika

Carriero

Zhu

et al. 2014

Science of The Total Environment

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• Our knowledge of ozone (O 3 ) effects on dynamic stomatal response is still limited.• Determinants of O 3 -induced stomatal sluggishness were examined in deciduous tree species in open-top chambers.• Ozone exposure slowed closing of stomata after leaf cutting.• Stomatal sluggishness was well explained by stomatal O 3 flux per net photosynthesis.• Stomatal sluggishness depended both on ozone flux and on the capacity for detoxification or repair. a b s t r a c t a r t i c l e i n f o Our knowledge of ozone effects on dynamic stomatal response is still limited, especially in Asian tree species. We thus examined ozone effects on steady-state leaf gas exchange and stomatal dynamics in three common tree species of China (Ailanthus altissima, Fraxinus chinensis and Platanus orientalis). Seedlings were grown and were exposed to three levels of ozone in open-top chambers (42, 69, 100 nmol mol −1 daylight average, from 09:00 to 18:00). At steady-state, ozone exposure induced an uncoupling of photosynthesis and stomatal conductance, as the former decreased while the latter did not. Dynamic stomatal response was investigated by cutting the leaf petiole after a steady-state stomatal conductance was reached. Ozone exposure increased stomatal sluggishness, i.e., slowed stomatal response after leaf cutting, in the following order of sensitivity, F. chinensis N A. altissima N P. orientalis. A restriction of stomatal ozone flux reduced the ozone-induced sluggishness in P. orientalis. The ozone-induced impairment of stomatal control was better explained by stomatal ozone flux per net photosynthesis rather than by stomatal ozone flux only. This suggests that ozone injury to stomatal control depends both on the amount of ozone entering a leaf and on the capacity for biochemical detoxification or repair. Leaf mass per area and the density of stomata did not affect stomatal sluggishness.

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Nocturnal stomatal conductance and ambient air quality standards for ozone

Cited by 116 publications

References 117 publications

Validation of Global Evapotranspiration Product (MOD16) using Flux Tower Data in the African Savanna, South Africa

Validation of Global Evapotranspiration Product (MOD16) using Flux Tower Data in the African Savanna, South Africa

Foliage surface ozone deposition: a role for surface moisture?

Determinants of stomatal sluggishness in ozone-exposed deciduous tree species

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