Which plant traits promote growth in the low-light regimes of vegetation gaps?

Abstract

Nine temperate grass species were screened for their potential to grow in the low-light conditions typical of gaps in dense vegetation. To this end, photosynthetic photon flux densities (PFD) were simulated in a growth chamber (PFD 100, 50 or 25 lmol photons m -2 s -1 ). Relative and absolute growth rates (RGR and AGR, respectively) of the species were regressed on ten different ecophysiological and morphogenetic plant attributes. No significant relationships were found between plant attributes and relative growth rate, while six attributes explained a significant proportion of the interspecific variance in absolute biomass growth: net photosynthetic rate at growth PFD (P net ) (75.5%), leaf apparent quantum yield of CO 2 fixation (62.5%), leaf dark respiration rate (65.2%), leaf compensation PFD (71.0%), root: shoot ratio (66.4%) and plant nitrogen content on a mass basis (42.0%). Only species with extremely low allocation to roots and very high (relatively speaking) net photosynthetic rates were able to grow fast in low light. Specific leaf area (SLA), instantaneous photosynthetic nitrogen use efficiency (PNUE) and leaf nitrogen content on a mass basis as well as on an area basis were not significantly related to growth. The absence of effects of plant traits on RGR, unlike for AGR, could arise from a relationship that we observed between AGR and a fitted start value of the biomasstime course (i.e. seed mass or germination time). This suggests that interspecific differences in the very early growth stages of the plants were responsible for differences in successful development under low light, rather than differences in RGR. Based on its high explanatory power, its relative constancy with plant age and the lack of effect of growth PFD, P net would be the best candidate for characterizing potentially shadetolerant species that are likely to establish in dense vegetation in the field.

Grass strategies and grassland community responses to environmental drivers: a review

“…Plants living in dense herbaceous communities, on forest understories or even in grassland gaps (Seidlova et al 2009), experience a strong reduction in radiation intensity and particularly in photosynthetically active radiation (PAR, 400-700 nm). At the same time, they experience light quality changes because of wave length-dependent light absorption and reflection by surrounding vegetation (Franklin 2008;Gommers et al 2013).…”

Effects of low irradiation on photosynthesis and antioxidant enzyme activities in cucumber during ripening stage

“…The study has reported that LI stress significantly reduced the chlorophyll content in leaves of Arabidopsis thaliana (Tanaka and Tanaka 2005), henbit genus (Haliapas et al 2008), and rice (Yamazaki 2010). In addition, LI stress could increase the plant height and leaf area, but reduced the number of plant shoots, leaves, flower buds, leaf thickness and yield (Schultz and Matthews 1993, Potter et al 1999, Correll and Weathers 2001, Shen et al 2002, Barisic et al 2006, Baltzer and Thomas 2007, Seidlova et al 2009, Hou et al 2010.…”

Limits to local spatial spread in a highly invasive annual grass (Microstegium vimineum)

“…Life history features of potential plant invaders are also important (Sakai et al 2001;Myers and Bazely 2003); for example, not every species abundant along a forest edge will necessarily be able to tolerate canopy closure in the forest interior (Honu and Gibson 2006;Seidlova et al 2009). For many invasive species, the question arises as to what ecological factors might limit their spatial spread and thus minimize their ability to invade new sites.…”