Leaf optical responses to light and soil nutrient availability in temperate deciduous trees

Abstract

Leaf optical parameters influence light availability at the cellular, leaf, and canopy scale of integration. While recent studies have focused on leaf optical responses to acute plant stress, the effects of changes in plant resources on leaf optics remain poorly characterized. We examined leaf optical and anatomical responses of five temperate deciduous tree species to moderate changes in nutrient and light availability. Spectral reflectance in the visible waveband generally increased at high light, but decreased with increased nutrient availability. Patterns of both spectral reflectance and absorptance were primarily determined by chlorophyll concentration although carotenoid concentration was also influential. While most anatomical features did not explain residual variation in reflectance, cuticle thickness was significantly related to reflectance at complementary angles compared to the angle of incidence. Absorptance did not change with light environment; however, absorption efficiency per unit biomass increased by approximately 40% under low light, due to reduced leaf mass per area. We conclude that changes in resource availability differentially influence leaf optical properties and that such changes are driven primarily by changes in pigment concentrations. The magnitude of leaf optical responses to moderate changes in resource availability was comparable to those of acute stress responses and varied among species.

Índices para avaliar o estado de nitrogênio da batata multiplicada por distintos materiais propagativos

“…A cor verde reflete pouca energia radiante. Deficiências de nutrientes com reflexo na concentração de clorofila e de carotenóides têm influência sobre a absorção e reflexão da luz na folha (Baltzer & Thomas, 2005). Assim, os índi-ces relacionados com a intensidade da cor verde das folhas da batata podem ser afetados por fatores que não a disponibilidade de N, como por exemplo, ano, localidade (Minotti et al, 1994) e material de propagação (Sampaio Júnior et al, 2008).…”

Morphogenetic trends in the morphological, optical and biochemical features of phyllodes in Acacia mangium Willd (Mimosaceae)

“…High proportions of chlorophyll and chlorophyll a/b ratio are considered to be an adaptation to increased red light absorption (Cao 1999). Leaf optical properties are driven both by leaf anatomical structure and by chlorophyll concentration (Lee et al 1990;Baltzer and Thomas 2005). Carotenoid content is positively related to the photoprotection phenomenon (Foyer 1993).…”

Functional leaf traits of 57 woody species of the Araucaria Forest, Southern Brazil

“…The internal organization observed on leaves from all lower strata, as well as the thickness of their tissues, is the common pattern found in ombrophyllous forests (Bongers and Popma 1990;Schneider et al 2003;Boeger et al 2004;Baltzer and Thomas 2005), where there is low light availability on the understory. The presence of one palisade parenchyma layer associated to the ratio of spongy/palisade parenchyma [1 in most leaves of the lower strata indicates an optimization for diffuse light capture (Vogelmann et al 1996).…”