The physiological advantage of an ecological filter species, Indocalamus longiauritus, over co‐occurring Fagus lucida and Castanopsis lamontii seedlings

Abstract

Indocalamus longiauritus (a dwarf bamboo) dominates forest understory and functions as an ecological filter to hinder the regeneration of canopy tree species in many temperate forests. However, the physiological mechanism underlying the function of ecological filters is not clear. In this study, we measured leaf-level carbon capture ability and use efficiency of the dwarf bamboo and the co-existing Fagus lucida (beech) and Castanopsis lamontii (chinkapin) seedlings in forest understory and small gaps in a beech-chinkapin mixed forest in the summer of 2005. The results indicated that I. longiauritus exhibited greater carbon capture ability, as indexed by light-saturated photosynthetic rate (P max ), maximal carboxylation rate, maximal electron transport rate and carboxylation efficiency, than the co-occurring F. lucida and C. lamontii seedlings in both forest understory and small gaps. Higher carbon capture ability in I. longiauritus was related to its greater partition of absorbed light energy to photochemistry. I. longiauritus had higher photosynthetic nitrogen use efficiency than F. lucida and C. lamontii seedlings in both light environments. However, water use efficiency (WUE) in I. longiauritus was higher than F. lucida but lower than C. lamontii. This intermediate WUE in I. longiauritus was related to its intermediate light-saturated stomatal conductance.In addition, I. longiauritus reduced metabolic cost by increasing the ratio of P max to respiration rate, leading to increased net carbon balance. On the other hand, F. lucida and C. lamontii seedlings had greater plasticity of carbon capture ability and leaf structural traits, which might facilitate colonization of gaps and realization of natural regeneration in these species.Keywords Dwarf bamboo AE Beech-chinkapin mixed forest AE Ecological filter AE Carbon capture ability and use efficiency AE Physiological mechanismList of symbols C a CO 2 concentration external to leaf (lmol mol À1 ) C i CO 2 concentration in the intercellular space (lmol mol À1 ) CE Carboxylation efficiency (lmol m À2 s À1 ) Chl n Ratio of leaf chlorophyll to leaf nitrogen in light-harvesting components (mmol g À1 ) Chl area Area-based leaf chlorophyll content (mg m À2 ) Chl mass Mass-based leaf chlorophyll content (mmol g À1 ) F 0 Minimal fluorescence in the dark F m Maximal fluorescence in the dark F s Steady-state fluorescence in the light F 0 m Maximal fluorescence in the light g smax Light-saturated stomatal conductance (mmol m À2 s À1 ) J max Maximal electron transport rate (lmol m À2 s À1 ) J mc Potential rate of photosynthetic electron transport per unit cytochrome f (lmol lmol À1 s À1 ) K c Michaelis-Menten constant of Rubisco for carboxylation (lmol mol À1 ) K o Michaelis-Menten constant of Rubisco for oxidation (mmol mol À1 ) LCP Light compensation point (lmol m À2 s À1 )LMA Leaf mass per area (g m À2 ) LVPD Leaf-to-air vapor pressure deficit (kPa) N area Area-based leaf nitrogen content (g m À2 ) N mass Mass-based leaf nitrogen content (g g À1 ) OIntercellular oxygen conce...

Comparison of dwarf bamboos (Indocalamus sp.) leaf parameters to determine relationship between spatial density of plants and total leaf area per plant

“…Bai et al. () report that Indocalamus longiauritus can dominate forest understory and function as an ecological filter. The genus can also provide habitats for birds and lizards.…”

“…Bamboos of Indocalamus, or dwarf bamboos are common wild plants in the rural areas of southern China. Bai et al (2011) report that Indocalamus longiauritus can dominate forest understory and function as an ecological filter. The genus can also provide habitats for birds and lizards.…”

Modular, hollow culms of rain-forest bamboos explain their persistence across a wide range of light environments

“…There remains an open question about what exact mechanisms enable bamboos to establish in canopy gaps and to survive under a closed canopy (Swaine & Whitmore 1988). Previous studies hypothesized that the capability of bamboos to exploit a wide range of light conditions is explained by plasticity in leaf traits (Montti et al 2014, Yang et al 2014 and in genet architecture (Widmer 1998) since photosynthetic capacity of bamboos does not differ substantially from cooccurring woody trees (Bai et al 2011, Dierick et al 2010, Saha et al 2009.…”

“…2014) and in genet architecture (Widmer 1998) since photosynthetic capacity of bamboos does not differ substantially from co-occurring woody trees (Bai et al . 2011, Dierick et al . 2010, Saha et al .…”