Site fertility and the morphological and photosynthetic acclimation of Pinus sylvestris needles to light

Abstract

Morphological and photosynthetic acclimation of current-year needles to canopy gradients in light availability (seasonal mean integrated quantum flux density, Q(int)) was studied in the temperate conifer, Pinus sylvestris L., at two sites of contrasting nutrient availability. The nutrient-rich site supported a monospecific P. sylvestris stand on an old-field. The trees were approximately 30 years old and 19-21 m tall. Mean foliar N and P contents (+/- SD) were 1.53 +/- 0.11% and 0.196 +/- 0.017%, respectively. The nutrient-poor site was located on a raised bog supporting a sparse stand of 50- to 100-year-old trees, with a height of 1-2 m, and mean needle N and P contents of 0.86 +/- 0.12% and 0.074 +/- 0.010%, respectively. At both sites, needle thickness (T) and width (W) increased with increasing Qint, and leaf dry mass per unit leaf area (MA) was also greater at higher irradiance. The light effects on MA-the product of needle density (D) and volume to total area ratio (V/AT)-resulted primarily from large increases in V/AT with Qint rather than from modifications of D, which was relatively insensitive to light. Although needle morphology versus light relationships were qualitatively similar at both sites, needles were shorter, and the slopes of W, T, MA and V/AT versus light relationships were lower, at the nutrient-poor than at the nutrient-rich site, indicating that the plasticity of foliar morphological characteristics was affected by nutrient availability. As a result of lower plasticity, needles at the nutrient-poor site were narrower, thinner, and had lower MA at high irradiance than needles at the nutrient-rich site. The maximum carboxylase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Vcmax) and the maximum photosynthetic electron transport rate (Jmax) scaled positively with foliar N and P contents. The correlations were generally stronger with P than with N, suggesting that needle photosynthetic capacity was more heavily limited by the availability of P than of N. The Jmax/Vcmax ratio was positively related to the foliar P/N ratio, indicating that Jmax was more strongly suppressed than Vcmax under conditions of low P availability. Phosphorus and N deficiency also limited the plasticity of foliar photosynthetic characteristics. There was a moderate increase in needle photosynthetic capacity of up to 1.6-fold from the bottom to the top of the canopy at the nutrient-rich site, but net assimilation rates were essentially independent of canopy position at the nutrient-poor site. Stomatal constraints on photosynthesis were similar between the sites, indicating that photosynthetic acclimation was curtailed at the biochemical level. We conclude that the foliar capacity for morphological and physiological acclimation to high light significantly decreases with decreasing nutrient availability in P. sylvestris, and that both N and P availability are potentially important determinants of foliar carbon gain capacities.

Anatomical structure and localisation of lignin in needles and shoots of Scots pine (Pinus sylvestris L.) growing in a habitat with varying environmental characteristics

“…Several researches into the morphological and physiological characteristics of needles (Niinemets et al, 2001(Niinemets et al, , 2002a(Niinemets et al, , 2002bNiinemets & Lukjanova, 2003) have revealed a strong dependence of the structure of the needles and shoots, the architecture of the shoot and crown geometry of the tree on the mineral composition of the soil. Needles from trees growing in nutrient-poor soil are thinner, narrower and with lower photosynthetic activity than needles from nutrient-rich sites.…”

“…It can grow in different climatic zones and soil conditions, both on sand and in bogs (Valk, 2005). The pines growing in various environmental conditions have differences in crown geometry, shoot architecture and the morphology of needles and shoots (Niinemets et al, 2001;2002a,b;Niinemets & Lukjanova, 2003). Numerous physiological and biochemical mechanisms are involved in the process of adaptation of plants to stressful and adverse conditions.…”

Concentración de carbono en Pinus cembroides Zucc: fuente potencial de mitigación delcalentamiento global

“…Para Thomas y Martin (2012), los volátiles implican concentraciones de C que deben considerarse en las evaluaciones de dicho elemento en las especies forestales. Las hojas fueron el componente que ocupó el segundo lugar en la capacidad para almacenar C. Algunos autores argumentan que a pesar de tener menor cantidad de celulosa, las hojas son ricas en sustancias volá-tiles de alta concentración de C, por los procesos de fotosín-tesis que ahí ocurren (Niinemets, Ellsworth, Lukjanova & Tobias, 2001;Yerena et al, 2011). En contraste, el fuste y la rama tuvieron los valores más bajos, siendo similares entre sí.…”

Variability of morphological needle traits of Scots pine (Pinus sylvestris L.) among populations from mountain and lowland regions of Poland

“…They result mainly from the different susceptibility of those traits to environmental factors (Żelawski and Gowin 1966, Irvine et al 1998, Niinemets et al 2001, Urbaniak et al 2003. Paying special attention to these kind of aspects related to differentiation is crucial in our case -comparisons of populations originating from contrasting natural habitats.…”

“…The probable explanation for the observed differences lies in the different edaphic conditions in the places where they grow. The response of pine to extreme habitat conditions by producing shorter needles is known (Niinemets et al 2001;Urbaniak et al 2003), and such conditions are present in the case of the L1 population (poor and sandy dune soil). The influence of stress on pine in this population also manifests itself in high values of skewness (Tab.…”