Photosynthetic characteristics and light energy conversions under different light environments in five tree species occupying dominant status at different stages of subtropical forest succession

Abstract

In order to reveal the mechanism of succession in subtropical forest along a light gradient, we investigated photosynthetic physiological responses to three light environments in five tree species including a pioneer species Pinus massoniana Lamb., two mid-successional species Schima superba Gardn. et Champ. and Castanopsis fissa (Champ. ex Benth.) Rehd. et Wils., and two late-successional species Cryptocarya concinna Hance. and Acmena acuminatissima (BI.) Merr et Perry) that were selected from Dinghu Mountain subtropical forest, South China. Results showed that, among the three kinds of species in all light conditions (100%, 30% and 12% of full sunlight), the pioneer species had the highest photosynthetic capacity (Amax), light saturation point (LSP), carboxylation efficiency (CE) and maximum utilisation rate of triose phosphate (TPU) that characterised a strong photosynthetic capacity and high carbon dioxide uptake efficiency. However, a higher light compensation point (LCP) and dark respiration (Rd) as well as lower apparent quantum yield (AQY) indicated that the pioneer specie cannot adapt to low light conditions. Mid-successional species had photosynthetic characteristics in between pioneer and late-successional species, but had the greatest effective quantum yield of PSII (ΦPSII) and light use efficiency (LUE, expressed in terms of photosynthesis). In contrast to pioneer and mid-successional species, late-successional species had lower photosynthetic capacity and carbon uptake efficiency, but higher shade tolerance and high-light heat dissipation capacity, as characterised by higher levels of total xanthophyll cycle pigments (VAZ) and de-epoxidation state of xanthophyll cycle (DEPs). These results indicate that photosynthetic capacity decreases along the successional axis and that late-successional species have more responsive heat dissipation capability to compensate for their inferior photosynthetic capacity.

Variations in photoprotective potential along gradients of leaf development and plant succession in subtropical forests under contrasting irradiances

“…Mature leaves of late-successional species have been demonstrated to have a lower photosynthetic efficiency than earlier successional species in subtropical forests (Zhu et al, 2013;Zhang et al, 2015;Zhu et al, 2016). This study further showed that young leaves of late-successional species also had lower photosynthetic efficiency than those of mid-successional species in both FL and LL (particularly in LL), as reflected by Chl content, Rubisco content, Pn, CE, ΦPSII and JC (Figs.…”

“…However, when late-successional species are exposed to excess light, such as sunflecks in the understory, strong light in the canopy or canopy gaps, reduced photosynthetic efficiency can result in late-successional species encountering greater photo-oxidative stress than earlier successional species. Many late-successional species can acclimate to strong light by enhancing photoprotection mediated by xanthophylls in mature leaves (Zhang et al, 2012;Zhang et al, 2015). In regard to young leaves, however, little is known about the photoprotective tools they use to cope with excess light.…”

Photosynthetic characteristics and growth performance of lettuce (Lactuca sativa L.) under different light/dark cycles in mini plant factories

“…The RD value reflects the plant's consumption of photosynthetic products. Both the LCP and RD were enhanced by the C12 treatment compared to the C6 and C3 treatments, implying that the long light cycle increased the consumption of photosynthetic products, resulting in a relatively inefficient use of resources (Zhang et al 2015). There was no significant difference in the AQY between the three light cycles, indicating that the influence of light/dark cycles on the ability of lettuce to use low light energy was not notable.…”

Shedding light on shade: ecological perspectives of understorey plant life

“…Avoidance of low light by escaping the understoreye.g. through allometric adjustments -is a third strategy, followed by certain shade intolerant plants when they germinate in the shade or when neighbours' growth decreases light availability (Henry and Aarssen 1997;Zavala et al 2011;Zhang et al 2015). Whereas the first two strategies allow plants to persist in the understorey for long periods of time, and are thus characteristic of shade tolerant plants, the third strategy can only be successful in coping with shade for a short period of time as plants that invest heavily in greater stem extension are unable to also invest in leaf construction.…”

“…Shade can act directly to limit photosynthesis but it can also act indirectly on the potential for carbon gain through morphological and physiological acclimation responses (Niinemets and Valladares 2004;Niinemets 2007;Laanisto and Niinemets 2015). Vegetation dynamics and succession in many communities is primarily driven by interspecific differences in resource uptake and stress tolerance, with light frequently being a key resource (Canham et al 1994;Jucker et al 2015;Zhang et al 2015). Thus, differences in shade tolerance between co-occurring species are central to ecosystem dynamics and community ecology.…”