Studies on Estimation of Leaf Gas Exchange of Ornamental Woody Plant Species

Abstract

Abstract. Instrumental measurements were carried out on urban tolerant Acer, Fraxinus, and Tilia species and varieties in the Buda Arboretum (N 47°28'47.7" E 19°02'19.6") in order to evaluate differences between their photosynthetic and gas exchange performance. Stomatal conductance, transpiration, net photosynthesis and photosynthetic active radiation (PAR) on sample leaves were measured and calculated using the LCi infrared gas analyzer (IRGA). Meanwhile the photosynthetic activity (net CO 2 assimilation) of leaves showed correlation to PAR, stomatal conductance and leaf temperature, there are significant differences found between genera and species of urban trees, which suggests that their CO 2 assimilation capacity differs. This influences the value of genera and species considering the urban air cleaning due to their CO 2 fixation. Under the examined conditions leaves of Tilia sp. showed higher photosynthetic capacity compared to Acer or Fraxinus sp. The transpiration rate of leaves correlates to stomatal conductance and leaf temperature. The low transpiration rate of Fraxinus excelsior 'Westhof's Glorie' leaves suggests more economic water use. We also found considerable differences in water use efficiency (WUE) between species and genera. Tilia sp. Acer platanoides and Fraxinus excelsior 'Westhof's Glorie' showed higher WUE compared to Acer negundo.

Responses of maize crop (Zea mays L.) to foilar spraying with humic acid at different nitrogen levels

“…But for the intra cellular CO 2 concentration (C i ) the opposite effect was found without significant differences between the two hybrids. This result is in agreement of Forrai et al, (2012) they reported that there are no variations in interacellular CO 2 concentration between species. Adding 90 kg N/efd.…”

Leaf Gas Exchange Characteristics of Drought Stressed Linden (Tilia Sp.) Trees

“…The daily trend of net CO 2 assimilation (A) more or less followed the stomatal conductance; similarly to Forrai et al (2012) at maximum level we measured 10-14 μmol•m −2 •s −1 , which rapidly decreased to 2-6 μmol•m −2 •s −1 to the early afternoon hours. Under drought stress the low stomatal conductance strongly controlled the carbon assimilation of Tilia leaves, which resulted significant differences in the daily accumulated carbon gain (Fig 4 .).…”

A novel root‐to‐shoot stomatal response to very high CO2 levels in the soil: electrical, hydraulic and biochemical signalling

“…A, B and C respectively). The theoretical relationship between T leaf and both g s and transpiration rate (Jones ) has previously been demonstrated experimentally (Prytz et al , Lake and Woodward , Forrai et al , Janka et al ); indeed, T leaf is used to compute total conductance to water vapour in infrared gas analyser (IRGA) systems (Licor Inc.) and is now in widespread use in infrared thermographic screening equipment for water‐related plant traits (Kim et al ).…”