Utilization of lightflecks by seedlings of five dominant tree species of different subtropical forest successional stages under low-light growth conditions

Abstract

We selected five typical tree species, including one early-successional species (ES) Pinus massoniana Lamb., two mid-successional species (MS) Schima superba Gardn. et Champ. and Castanopsis fissa (Champ. ex Benth.) Rehd. et Wils. and two late-successional species (LS) Cryptocarya concinna Hance. and Acmena acuminatissima (BI.) Merr et Perry., which represent the plants at three successional periods in Dinghushan subtropical forest succession of southern China. Potted seedlings of the five species were grown under 12% of full sunlight for 36 months. The ES and MS showed the slowest and fastest responses to lightflecks, respectively, which correlated with the rate of stomatal opening. In contrast to P. massoniana and C. concinna, the other three species exhibited a high induction loss. Early-successional species showed the lowest specific leaf area and chlorophyll content, the highest photosynthetic capacity (A(max)) and respiratory carbon losses (R(d)). Compared with ES and MS, LS showed lower A(max) and R(d). The five tree species showed a similar chlorophyll a/b ratio after long-term low-light adaptations. On the other hand, LS had a relatively higher de-epoxidation state to protect themselves from excess light during lightflecks. Our results indicated that (i) slower responses to lightflecks could partially explain why ES species could not achieve seedling regeneration in low-light conditions; (ii) fast responses to lightflecks could partially explain why MS species could achieve seedling regeneration in low-light conditions; and (iii) smaller respiratory carbon losses might confer on the LS species a competitive advantage in low-light conditions.

“Diminishing returns” in the scaling of leaf area vs. dry mass in Wuyi Mountain bamboos, Southeast China

“…Leaf plasticity to differences in light intensity, known to effect changes in photosynthetic and respiration rates, has been extensively studied in many woody plant species (see Poorter and Oberbauer, 1993; Küppers et al, 1996; Hanba et al, 2002; Chen et al, 2011; Zhang et al, 2012). Typically, plants respond to changing light conditions by adjusting a suite of morphological and physiological traits, such as leaf area and leaf mass and thus specific leaf area (SLA).…”

Stomatal Size, Speed, and Responsiveness Impact on Photosynthesis and Water Use Efficiency

“…They will also depend on plant water status (Fig. 4), the history of stress Porcar-Castell and Palmroth, 2012;Wong et al, 2012;Zhang et al, 2012), leaf age (Urban et al, 2008), and the magnitude and duration of the change Figure 3. Effects of shade flecks on A and g s in P. vulgaris (A-C) and V. faba (D-F).…”

Morpho-physiological acclimation to canopy coverage of Araucaria angustifolia during the establishment in the Atlantic Forest, Argentina

“…The removal of trees of the upper stratum, either by anthropic interven-tion or by natural causes, generates openings in the canopy (gaps) that increase the sunlight that arrive to the understory. However, more subtle changes in the magnitude and spatial distribution of light under closed canopies can also influence long-term survival and recruitment of seedlings (Zhang et al 2012). Plants can adjust genotype expression in response to those changes in light availability, in order to change phenotype to tolerate or optimize light interception and use (Vieira et al 2015).…”