Inter‐ and intra‐specific variability in isoprene production and photosynthesis of Central European oak species

Abstract

European deciduous oaks are closely related and are known for their strong emission of volatile isoprenoids. They are chemo-taxonomically diverse, but hybridise frequently. Four-year-old oak seedlings growing together in a model ecosystem facility under near-natural conditions were studied. The leaves were morphologically classified in the three oak species Quercus robur, Q. pubescens and Q. petraea (with four provenances each) and further investigated by a molecular-genetic approach. Q. robur was morphologically and genetically clearly different from Q. pubescens and Q. petraea, whereas Q. pubescens and Q. petraea individuals used in this study were morphologically and genetically more similar. There was a minor impact of among and within species variability on isoprene synthesis, isoprene emission and photosynthesis. Isoprene emission rates normalised to 25 °C leaf temperature ranged from 5.78 to 10.66 nmol m(-2) s(-1) , whereas photosynthesis ranged from 12.8 to 17.6 μmol m(-2) s(-1) . On cloudy days, among the provenances of each species, only net photosynthesis of the Q. robur provenance Hünenberg was reduced and isoprene synthase activity of the Q. pubescens provenance Promotogno increased. On sunny days, photosynthesis did not differ among the provenances. Over all provenances, gas exchange on cloudy days did not differ significantly from sunny days. In the combined data of cloudy and sunny days, no differences between the studied provenances and oak species were detected in isoprene emission and photosynthesis. Thus, isoprene emission and photosynthesis rates were remarkably stable among oak species and provenances. The results indicate that taxonomic differences in the studied oak species are not reflected in isoprene emission and photosynthesis, probably because of the high plasticity of gene expression resulting in high phenotypic flexibility.

Cell‐level anatomical characteristics explain high mesophyll conductance and photosynthetic capacity in sclerophyllous Mediterranean oaks

“…However, contrary to expectations, Flexas et al (2014) found that despite having higher average LMA, Mediterranean species, on average, have similar photosynthetic capacity on an area basis as plants from any other biomes. In fact, Peguero-Pina et al (2009) reported values of net CO 2 assimilation rate for Mediterranean oaks Quercus coccifera, Quercus ilex and Quercus suber that were very similar to those found in other temperate oak species with lower LMA, such as Quercus robur, Quercus petraea, Quercus cerris, Quercus rubra or Quercus prinus (Epron et al, 1992(Epron et al, , 1993Valentini et al, 1995;Turnbull et al, 2002;Cano et al, 2013;Steinbrecher et al, 2013;Peguero-Pina et al, 2016b). A possible explanation for these contradictory findings was provided by Flexas et al (2014), who hypothesized that high LMA in Mediterranean species is also responsible for the enhanced capacity of carboxylation per area (V c,max ) due to increased Rubisco content per area in thicker leaves with more cell layers.…”

Variability of BVOC emissions from a Mediterranean mixed forest in southern France with a focus on <i>Quercus pubescens</i>

“…The smaller (by a factor of 2) Is observed for Qp3 compared to other O 3 HP tree branches was a posteriori explained by the fact that this branch died in August despite no injuries were visible during our study in June. By contrast Steinbrecher et al (2013) observed a remarkable stability of Is values from seedlings of various oak species originating from different environmental climates (precipitation, temperature) with a factor of only 1.6 for Q. pubescens Is.…”

“…Kesselmeier et al (1998) and Owen et al (1998) assessed a fairly similar Is of 50 and 66 µgC g −1 DM h −1 respectively at a site near Montpellier (France), which was 50 % lower than what Simon et al (2005) found 250 km from this site. On the other hand, Steinbrecher et al (2013) observed a remarkable Is stability from seedlings of various oak species (including Q. pubescens) originating from different environmental climates (precipitation, temperature) and coming from different European sites. Simpson et al (1999) proposed in their European BVOC inventory review an Is value of 53 µgC g −1 DM h −1 for Q. pubescens.…”

Promosi Kesehatan Pencegahan Hipertensi Sejak Dini

“…Kekuatan tekanan darah sangat dipengaruhi oleh aktivitas dan banyak faktor lain meliputi faktor predisposisi dan presipitasi seperti umur dan jenis kelamin, riwayat keluarga, genetik, stress, obesitas dan gaya hidup seperti merokok, konsumsi alkohol, dan diet yang tidak sehat (Wang, Tiwari and Wang, 2014). Penelitian menunjukan bahwa resiko hipertiensi meningkat seiring bertambahnya usia.…”