&lt;b&gt;Shading effects on leaf life span and functional traits in the widespread species &lt;i&gt;Enterolobium contortisiliquum&lt;i&gt; (Vell.) Morong

João Paulo Souza,Nayara Magry Jesus Melo,Jéssica Naiara Reis,Alessandro Dias Halfed

doi:10.4025/actascibiolsci.v39i1.33400

Abstract

Enterolobium contortisiliquum occurs in native forests formations from southeast to northeast Brazil, and too in Argentina, Bolivia and Paraguay. The objective of this study was to evaluate shading effects in the early growth of E. contortisiliquum plants. We measured leaf gas exchange, chlorophyll content index, biomass allocation and leaf development in plants in sunny and shaded areas. The experiment was performed in Universidade Federal de Vicosa , campus Florestal, Minas Gerais, Brazil. To determine the effects of different light regimes (full sunlight and shade) on the growth of E. contortisiliquum plants, we divided plants into two groups: plants grown in a greenhouse under full sunlight, and plants grown under 70% shade tissue. E. contortisiliquum plants grown in full sunlight showed an increase in maximum net photosynthesis, root, stem, and leaf dry mass, root length, root/stem ratio, and length of the stem. However, E. contortisiliquum under shade showed larger specific leaf area, leaf area ratio, chlorophyll content, long leaf life span, and slow growth. These ecophysiological adjustments in sunny and shaded areas may explain the wide geographical distribution of E. contortisiliquum in many vegetation types.

Highlights

Plants grown in shaded environments show a reduction in their maximum photosynthetic capacity, saturation irradiance to photosynthesis, and compensation point for light (Straus-Deberiedetti & Bazzaz, 1996)
Enterolobium contortisiliquum plants grown in sun had significantly higher (p < 0.05) values of Amax than plants grown in shade (Figure 1A) at all measurement points
Plants of E. contortisiliquum grown in shade had significantly higher values (p < 0.05) of chlorophyll a and total chlorophyll than plants grown in sun (Figure 1F, H)

Summary

Introduction

Plants grown in shaded environments show a reduction in their maximum photosynthetic capacity, saturation irradiance to photosynthesis, and compensation point for light (Straus-Deberiedetti & Bazzaz, 1996). Leaves of shaded plants have a high chlorophyll content, primarily chlorophyll b, which is related to an increase in the complex antenna size (Boardman, 1977). Under shade, plants invest more in leaf area than in mass (Gobbi, Garcia, Ventrella, Garcez, & Rocha 2011; Poorter, 1999). Plants grown in sunny areas have high leaf photosynthesis, stomatal conductance, and saturation irradiance of photosynthesis (Bazzaz, 1998; Chazdon, Pearcy, Lee, & Fetcher, 1996).

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