Leaf plasticity in response to light of three evergreen species of the Mediterranean maquis

Abstract

Morphological, anatomical, biochemical and physiological traits of sun and shade leaves of adult Quercus ilex, Phillyrea latifolia and Pistacia lentiscus shrub species co-occurring in the Mediterranean maquis at Castelporziano (Latium) were studied. Fully expanded sun leaves had 47% (mean of the three species) greater leaf mass area (LMA) and 31% lower specific leaf area (SLA) than shade leaves. Palisade parenchyma thickness contributed on an average 42% to the total leaf thickness, spongy layer 43%, upper epidermal cells 5%, and upper cuticle thickness 3%. Stomatal size was greater in sun (25.5 mu m) than in shade leaves (23.6 mu m). Total chlorophyll content per fresh mass was 71% greater in shade than in sun leaves, and nitrogen content was the highest in sun (13.7 mg g(-1)) than in shade leaves (11.8 mg g(-1)). Difference of net photosynthetic rates (P (N)) between sun and shade leaves was 97% (mean of the three species). The plasticity index (sensu Valladares et al., New Phytol 148:79-91, 2000a) was the highest for physiological leaf traits (0.86) than for morphological, anatomical and biochemical ones. Q. ilex had the highest plasticity index of morphological, anatomical and physiological leaf traits (0.37, 0.28 and 0.71, respectively) that might explain its wider ecological distribution. The higher leaf plasticity of Q. ilex might be advantageous in response to varying environmental conditions, including global change

Gochnatia polymorpha (Less.) Cabrera (Asteraceae) changes in leaf structure due to differences in light and edaphic conditions

“…8) we encountered a good relationship between leaf thickness and palisade parenchyma (r 2 =0.94, p < 0.01), showing that the main tissue responsible for increasing leaf thickness is the palisade parenchyma. This layer contributed approximately 50% of leaf thickness; similar values are found in Mediterranean species (Gratani et al 2006). Thicker leaves in gallery forest occurred because of an increase in palisade and in spongy parenchyma thickness (this layer was responsible for 32% of leaf thickness in this condition) which promotes higher photosynthetic rates due the increase in CO 2 concentration (Pearce et al 2006).…”

Características funcionais de folhas de sol e sombra de espécies arbóreas em uma mata de galeria no Distrito Federal, Brasil

“…As diferenças fi siológicas encontradas entre folhas de sol e sombra também são atribuídas parcialmente a diferenças na estrutura foliar (Gratani et al 2006), sendo a área foliar específi ca um parâmetro diretamente relacionado ao investimento em estruturas foliares. A área foliar específi ca é uma variável altamente plástica e dependente das condições ambientais, principalmente a luz (Grime 1979, Dahlgren et al 2006.…”

“…Por outro lado, espera-se que folhas de sol dos mesmos indivíduos apresentassem maiores taxas fotossintéticas, em termos de área, em função de uma maior capacidade no transporte de elétrons em comparação com folhas de sombra. Dessa forma, foi testada a esperada divergência (Gratani et al 2006) entre folhas de sol e sombra para as variáveis relacionadas à captação de luz, trocas gasosas e conteúdo foliar de nutrientes.…”

Variações fenotípicas em Andira fraxinifolia Benth. (Fabaceae) em duas fitofisionomias de Restinga

“…Portanto, as folhas podem ser consideradas um órgão altamente plástico e aclimatável aos fatores ambientais (Gratani et al 2006), sendo a intensidade luminosa, a disponibilidade hídrica e a temperatura os principais fatores que podem influenciar suas variações (Esau 1977). O caule também tem a capacidade de registrar na madeira os eventos microclimáticos e variações sazonais no ambiente, como a oferta ou a escassez de nutrientes minerais e água (Kedrov 2012).…”