Light‐dependent photosynthetic characteristics indicated by chlorophyll fluorescence in five mangrove species native to Pohnpei Island, Micronesia

Abstract

To investigate the adaptive capacity to strong light among mangrove species, we examined light-dependent properties of photosynthesis in relation to photoinhibition using chlorophyll fluorescence for sun-leaves of five mangrove tree species; Sonneratia alba, Rhizophora stylosa, Rhizophora apiculata, Bruguiera gymnorrhiza and Xylocarpus granatum. These species were classified into three groups; pioneer -S. alba and R. stylosa, intermediate -R. apiculata and B. gymnorrhiza and climax species -X. granatum. A further distinction can be made between the two intermediate species, the less shade-tolerant R. apiculata and the shade-tolerant B. gymnorrhiza. There was a clear association between successional status and light-saturated electron transport rate (ETR) where ETR was higher in S. alba and R. stylosa > R. apiculata and B. gymnorrhiza > X. granatum. Based on its lower initial slope of light-dependent ETR and lower ratio of variable to maximum fluorescence (Fv/Fm) after a dark-adaptation, X. granatum appeared to suffer greater photoinhibition than other species. The response of qP, which represents PSII openness, to incident light indicates a ranking of tolerant capacity to photoinhibition of S. alba and R. stylosa > R. apiculata > B. gymnorrhiza and X. granatum. The difference in qP response between R. apiculata and B. gymnorrhiza might be attributed to the higher leaf absorptance and the lower degree of thermal dissipation indicated by the higher F'v/F'm in B. gymnorrhiza. It appears that the co-ordination of leaf absorptance, thermal dissipation and consumption of absorbed light energy through electron transport is important in the acclimation of mangrove species to exposed habitats.

Seasonal changes in photoprotective mechanisms of leaves from shaded and unshaded field-grown coffee (Coffea arabica L.) trees

“…Also, since chronic photoinhibition occurs in a period of restrained growth, associated with a build-up in carbohydrate content (Silva et al 2004), it is unlikely that photoinhibition per se would largely result in decreased coffee productivity. Furthermore, photoinhibited outer leaves may play a role to attenuate light intensity and so protect inner leaves from photoinhibition (Kitao et al 2003). Finally, the present results suggest that shading would result in little, if any, additional photoprotection to the peripheral leaves.…”

Growth, crown architecture and leaf dynamics of saplings of five mangrove tree species in Ranong, Thailand

“…In addition, shade saplings of X. granatum surprisingly increased total leaf area to the same extent that sun saplings did (Fig. 4b), probably because of a negative influence of high light on sun leaves due to less effective protective mechanisms against photoinhibition (Kitao et al 2003).…”

“…a high turnover rate of leaves) is often associated with a higher relative growth rate and a higher photosynthetic assimilation rate (Reich et al 1991). Kitao et al (2003) reported that the light-saturated electron transport rate, which can be correlated with the photosynthetic rate, was highest in Sonneratia alba, followed by Rhizophora apiculata and Bruguiera gymnorhiza, and was lowest in Xylocarpus granatum (Avicennia alba was not measured). The result from the present study that leaf longevity is negatively correlated with RHGR in gaps implies that leaf-level traits (leaf turnover and photosynthesis) correspond directly to the individual-level growth rate in mangrove saplings.…”

Variation in photoinhibition among Sasa senanensis, Quercus mongolica, and Acer mono in the understory of a deciduous broad-leaved forest exposed to canopy gaps caused by typhoons

“…Energy consumption via photosynthetic electron transport connected to PS II is an important factor in photoinhibition avoidance (Ö quist et al 1993;Baroli and Melis 1998;Kitao et al 2003Kitao et al , 2006b). In the present study, species with higher ETR capacity (Fig.…”