Acclimation of photosystem II to high temperature in two Wedelia species from different geographical origins: implications for biological invasions upon global warming

Abstract

More intense, more frequent, and longer heat waves are expected in the future due to global warming, which could have dramatic ecological impacts. However, few studies have involved invasive species. The aims of this study were to examine the effect of extreme heating (40/35 degrees C for 30 d) on the growth and photosynthesis of an alien invasive species Wedelia trilobata and its indigenous congener (Wedelia chinensis) in South China, and to determine the development of this invasive species and its potential adaptive mechanism. In comparison with W. chinensis, W. trilobata suffered less inhibition of the relative growth rate (RGR) and biomass production due to high temperature, which was consistent with the changes of photosystem II (PSII) activity and net photosynthetic rate (P(n)). High temperature caused a partial inhibition of PSII, but the adverse effect was more severe in W. chinensis. Measurement of the minimum fluorescence (F(o)) versus temperature curves showed that W. trilobata had a higher inflexion temperature of F(o) (T(i)), indicating greater thermostability of the photosynthetic apparatus. Moreover, comparisons of absorbed light energy partitioning revealed that W. trilobata increased xanthophyll-dependent thermal dissipation (Phi(NPQ)) under high temperature, while retaining the higher fraction of absorbed light allocated to photochemistry (Phi(PSII)) relative to W. chinensis. The results suggest that the invasive W. trilobata has a high thermostability of its photosynthetic apparatus and an effective regulating mechanism in energy partitioning of PSII complexes to minimize potential damage and to retain greater capability for carbon assimilation. These factors confer greater heat stress tolerance compared with the native species. Therefore, the invasive W. trilobata may become more aggressive with the increasingly extreme heat climates.

Using the quantum yields of photosystem II and the rate of net photosynthesis to monitor high irradiance and temperature stress in chrysanthemum (Dendranthema grandiflora)

“…A decrease in PSII operating efficiency is always accompanied by an increase in NPQ [24,47], as a reversible down regulation of PSII under high irradiance conditions [18,48]. As Chrysanthemum are able to cope with excess irradiance at temperatures below 28 °C, we suggest that the process involved in acclimating the photosynthetic apparatus to high irradiance and temperature stress might be due to changes in the efficiency of the open PSII reaction centre and the dissipation of excess absorbed energy (NPQ) [48,49].…”

“…We suggest that high irradiance and temperature above 28 °C might limit the capacity of NPQ to regulate light capture by Chrysanthemum. In comparison, certain stress tolerant plant species are able to cope with high irradiance and high temperature by an effective regulating mechanism in energy partitioning of PSII complexes [49].…”

INVASION OF Acacia decurrens WILLD. AFTER ERUPTION OF MOUNT MERAPI, INDONESIA

“…IAPS can endure extreme temperature which makes them competitor to the native vegetation (Hellmann et al 2008;Ordonez et al 2010;Van Kleunen et al 2010). Song et al (2010) studied the effect of extreme high temperatures for the invasive Wedelia trilobata, and found out that in the extreme high temperature condition, W. trilobata experienced less inhibition of relative growth rate (RGR) and biomass production than the native plant Wedelia chinensis.…”

Biofuel: A Scope for Reducing Global Warming

“…For instance, high temperature impinge the seed germination and viability in the species like Juniperus communis, in addition to this, elevated CO 2 affect the growth and yield by inhibiting Photosystem II in some species of Wedelia as well as by reducing Rubisco content in rice species. Moreover, elevated CO 2 concentration and/or increased temperature trigger the susceptibility to pathogen mediated diseases in wheat and barley, which has been elaborated further in barley that by decreasing the amount of defense compound such as p-coumaroylhydroxyagmatine [16][17][18][19][20]. Moreover, increased CO 2 reduce the nutritional composition of some plants such as deplete Vitamin C content in Lycopersicon esculentum [21].…”