Photosynthetic Properties of Miscanthus condensatus at Volcanically Devastated Sites on Miyake-jima Island

Abstract

How photosynthetic-related leaf traits of non-nitrogen (N)-fixing pioneer species respond to extreme habitat conditions of primary succession is still not well-elucidated, especially in volcanically N-deplete habitats. The effect of N-deplete soil on photosynthetic-related leaf traits can provide a basis for predicting how plants adjust their strategies to adapt to such habitats. To examine the responses of leaf traits to extreme conditions, we investigated Miscanthus condensatus (a non-N-fixing C4 pioneer grass) which grows on a volcanically devastated area on Miyake-jima Island, Japan, in which the volcanic ash has been deposited for 17–18 years since the 2000-year eruption. Leaf N content (Narea), light-saturated photosynthetic rate (Amax), and photosynthetic N use efficiency (PNUE) in three contrasting study sites: bare land (BL), shrub land gap (SLG), and shrub land under canopy (SLUC) were determined. Results indicated that compared to previous studies and internal comparison of Miyake Island, M. condensatus in BL was able to maintain a relatively high Amax, Narea and PNUE. The higher Amax was in part a result of the higher PNUE. This is a characteristic necessary for its successful growth in N-deplete soils. These results suggest that M. condensatus has photosynthetic-related advantages for adaptation to volcanically N-deplete habitats.

Age Determination and Growth Characteristics of the Potentilla griffithii: A Comparison of Two Different Habitats in Western Sichuan Plateau, China

“…We considered that one critical factor is light intensity in the present study, which is considered as a primary factor limiting plant growth in alpine ecosystems [ 62 ]. The decrease in light intensity from open land to understory grassland is due to the gradually closing canopy structure [ 40 ]. The good light conditions in open land increase the above-ground proportion and further improve the additional light uptake capacity.…”

“…Studies have demonstrated that plant growth strategies are affected by the environment. For instance, there are significant differences in biomass accumulation, allocation, and morphological variation between open land and understory habitats [ 40 ]. When comparing similarly aged plants growing under different growth conditions, plants developing under light constraints tend to be smaller at a given age than plants growing under more favorable conditions, as seen by variations in root: shoot ratios [ 12 ].…”

Photosynthetic Properties of Co-Occurring Pioneer Species on Volcanically Devastated Sites in Miyake-jima Island, Japan

“…The average values of N area for F. japonica and A max for A. sieboldiana are even higher than the leaf traits from the N-rich habitat (Table A1). This reflects the relatively higher ability of these species to resist the N-low conditions in this volcanic environment; these plants also show an extremely low N requirement and demonstrate more effective N use strategies than the Miyake-jima pioneer species [11,39].…”

“…Several studies that have clarified the success pioneer species under harsh volcanic environments have focused on vegetation (growth form), life history (dormancy form), phenology, seed biology [4], biomorphology (e.g., root architecture, shoot shape), and seed viability (seed size/mass) [5,6]. However, from the perspective of photosynthetic-related leaf traits (including morphological, physiological), which are closely related to plant fitness and survival strategies [7] and are essential for the successful maintenance and expansion of populations, have received little attention [8][9][10][11].…”

“…Additionally, Choi et al [39] also proved its success in resisting high concentrations of volcanic gas (SO 2 ) in the Miyake-jima volcano. Regarding M. condensatus, our previous study [11] in the volcanically devastated site in Miyake-jima indicated that the relatively high light-saturated photosynthetic rate (A max ) and PNUE of M. condensatus were its adaptation advantages to volcanically N-deplete habitats. As for F. japonica, Sakata et al (2006) [40] indicated that at the higher activation state, the Rubisco in Aconogonum weyrichii (closely related species of F. japonica) can also be regarded as an adaptive feature in summer, as it allows for intensive dry-matter production within the short growing period.…”