Changes in photosynthesis during leaf expansion in Corymbia gummifera

Abstract

Growth, pigment levels and various photosynthesis parameters were measured in expanding leaves of Corymbia gummifera (Solander ex Gaertner) Hochreutiner. C. gummifera trees were studied growing in sandstone plateau woodland communities in Royal National Park, New South Wales, in a recently burned open habitat. Young leaves (horizontally oriented to maximise light exposure) were found to be conspicuously red until they reached approximately 75% of their full size. As the leaves expanded, anthocyanin content declined and chlorophyll levels proportionately increased. Young red leaves showed net negative carbon assimilation rates, although CO2 assimilation rate, transpiration rate, stomatal conductance, actual quantum yield of PSII (ΦPSII) and apparent electron transport rate (ETR) all increased in a similar pattern as the leaves expanded. Measurements of maximum quantum yield of dark-adapted leaves (Fv/Fm) were also correlated with leaf area. Younger leaves had lower Fv/Fm ratios than did mature leaves, whether measured at midday or 2 h after sunset, indicating that young leaves exhibited some degree of chronic photoinhibition. It is concluded that C. gummifera exhibits a transient red pattern of anthocyanin expression and that photosynthesis is limited in young leaves because of low stomatal conductance, low chlorophyll content, immature chloroplasts and an attenuation of light caused by anthocyanins.

Photosynthetic characterization of Jerusalem artichoke during leaf expansion

“…2a). This suggests that photosynthetic metabolism was gradually perfected along with leaf area expanding, and similar result also has been obtained in the studies on other plants (Roper and Kennedy 1986;Choinski et al 2003;Jiang et al 2006a, b, c;Maayan et al 2008). Stomatal conductance determines entry of CO 2 into the leaf and closely associates with Pn, and the close relation between Gs and Pn has been demonstrated in Ficus carica during leaf development recently (Gonzalez-Rodriguez and Peters 2010).…”

“…Thus, we suppose that leaf area expansion process also involved the synthesis and assembly of photosynthetic apparatus in Jerusalem artichoke. So far, it is not definite whether primary photochemical reaction of PSII is the limiting step of photosynthetic capacity during the leaf growth, as contradictory results have been reported in different plants (Lebkuecher et al 1999;Srivastava et al 1999;Choinski et al 2003;Jiang et al 2005Jiang et al , 2006c. These contradictory results can be attributed to the inconsistent culture protocol or plant species.…”

“…The maximal quantum yield of PSII (wPo) reflects the performance of primary photochemistry reaction. It was observed that wPo increased along with leaf growth (Choinski et al 2003). However, Jiang et al (2006c) suggested that primary photochemical reaction of PSII was almost built up at the early beginning of leaf development in grapevine, and they also inferred that oxygen evolving complex might be not perfectly connected to PSII in young leaves.…”

Photosynthetic Adaptive Strategies in Evergreen and Semi-Deciduous Species of Mediterranean Maquis During Winter

“…On the contrary, in mature leaves, more absorbed light was dissipated by thermal dissipation processes associated to xanthophylls cycle (higher  NPQ ). This result is in contrast with data reported by other authors who found a reduction in thermal dissipation by xanthophylls cycle as the leaves expanded (Choinski & Eamus, 2003;Jiang et al, 2005). Our data suggest that leaf age influences the photoprotection mechanisms.…”

Crown‐scale evaluation of spectral indices for defoliated and discoloured eucalypts

“…However, chlorophyll content can vary widely with leaf age in eucalypts (Choinski Jr et al 2003, Close et al 2004) and other genera (Mohammed et al 2000, Sims andGamon 2002). In eucalypts a common response to stress is production of anthocyanins, for example during photoinhibitory conditions (Close and Beadle 2003) or from biotic leaf damage (Stone et al 2000, Smith et al in press).…”