Integrated responses of rosette organogenesis, morphogenesis and architecture to reduced incident light in Arabidopsis thaliana results in higher efficiency of light interception

Abstract

Plants have a high phenotypic plasticity in response to light. We investigated changes in plant architecture in response to decreased incident light levels in Arabidopsis thaliana (L.) Heynh, focusing on organogenesis and morphogenesis, and on consequences for the efficiency of light interception of the rosette. A. thaliana ecotype Columbia plants were grown under various levels of incident photosynthetically active radiation (PAR), with blue light (BL) intensity proportional to incident PAR intensity and with a high and stable red to far-red light ratio. We estimated the PAR absorbed by the plant, using data from precise characterisation of the light environment and 3-dimensional simulations of virtual plants generated with AMAPsim software. Decreases in incident PAR modified rosette architecture; leaf area decreased, leaf blades tended to be more circular and petioles were longer and thinner. However, the efficiency of light interception by the rosette was slightly higher in plants subjected to lower PAR intensities, despite the reduction in leaf area. Decreased incident PAR delayed leaf initiation and slowed down relative leaf expansion rate, but increased the duration of leaf expansion. The leaf initiation rate and the relative expansion rate during the first third of leaf development were related to the amount of PAR absorbed. The duration of leaf expansion was related to PAR intensity. The relationships identified could be used to analyse the phenotypic plasticity of various genotypes of Arabidopsis. Overall, decreases in incident PAR result in an increase in the efficiency of light interception.

Plasticity to soil water deficit in Arabidopsis thaliana: dissection of leaf development into underlying growth dynamic and cellular variables reveals invisible phenotypes

“…In all accessions, the decrease in leaf expansion rate caused by water deficit was at least partly compensated for by an increase in the duration of leaf expansion. Opposite effects of environmental changes on the rate and duration of leaf expansion have been shown previously in A. thaliana plants subjected to different temperatures (Granier et al 2002) and reduced incident light (Chenu et al 2005;Cookson & Granier 2006). This phenomenon is also well known for temperature response in many plants (Granier & Tardieu 1998 on sunflower).…”

Acclimation to sun and shade of three accessions of the Chilean native berry-crop murta

“…5b, d), the same kind of response leaf photosynthesis shows to intercepted light (Larcher 2003). This kind of logarithmic response of meristematic activity to light absorbed by whole plants had previously been observed for Arabidopsis thaliana by Chenu et al (2005) who interpreted this as a response to assimilate availability in the meristems. Consistently, it has been shown that the amount of photosynthetic products in meristems directly relates to meristematic activity (Smeekens 2000;Pien et al 2001;Freixes et al 2002).…”

“…5b, d, f) indicating that the increments in photosynthesis with increasing amount of intercepted light no longer persists for high light transmittance levels. As previously discussed, photoinhibition may partly explain these results through its effect of depressing photosynthesis (Powles 1984) and hence plant growth (Ö gren and Sjö strö m 1990; Winter and Kö nig 1991;Liang et al 1995;Werner et al 2001) and assimilate availability in meristems (Chenu et al 2005). Another part of this effect of high light may be related to changes in leaf temperature induced by light transmittance.…”

Modelling foliage characteristics in 3D tree crowns: influence on light interception and leaf irradiance

“…Archimed is a simulation platform gathering biophysical models, including radiative models previously described by Dauzat and Eroy (1997) and by Chenu et al (2005). The principle of the simulations lays on numerical computation of directional radiative intercepted fluxes on virtual trees.…”