Geographical pattern in photosynthetic light response of Pinus sylvestris in Europe

Abstract

Summary1. The geographical aspects in photosynthetic light response and stomatal conductance in the shoots of Pinus sylvestris were studied together with structural properties of shoots and needles. Seven stands within the natural distribution area of P. sylvestris in Europe were chosen. CO 2 exchange, irradiance and stomatal conductance (g s ) for water vapour were measured and the maximum photosynthetic rate (P m ) was determined from the CO 2 exchange measurements. 2. There was a clear pattern in the average values of P m along the latitudinal gradient. Highest values of P m were found in the middle parts of the distribution area and they decreased towards both ends of the transect. The highest value was almost twice as high as the lowest one. 3. The between-site variation explained 70% of the total variation in the maximum photosynthetic rate. P m was not clearly correlated with any single climatic variable or nitrogen concentration in the needles. 4. P m was closely coupled with stomatal conductance (r 2 = 0·74). The differences in P m and g s between the sites is likely to reflect adaptation and acclimation to different climates.

Genetic variability of Pinus sylvestris populations from IUFRO 1982 provenance trial

“…Similar geographic pattern of genetic differentiation of Scots pine was also reported in our previous paper (Androsiuk et al 2011b), where north European populations of the species form separate, genetically very homogenous cluster. Individual character of northern and north-eastern Scots pine populations was pointed also by some physiological features like higher N and P resorption efficiency from senescing foliage (Oleksyn et al 2000(Oleksyn et al , 2003, earlier bud set (Garcia-Gil et al 2003), lower average maximum of photosynthetic rate (Luoma 1997) and slower above ground growth (Oleksyn et al 1999). These populations also share a great deal of similarity of first-year growth response to simulated 50° and 60° N photoperiod and are subsumed to the same photoperiod genotype (Giertych and Oleksyn 1992).…”

Does bulk-needle ?13C reflect short-term discrimination?

“…Pine needles have a complicated shape and are twisted to different degrees, therefore, in this case, complete surface area was calculated and used to standardise measurements. Based on a survey of the shape of pine needles (N = 5; resolution of 5 mm along the length of the needles), a mathematical model using a half elliptical cone stump and two measuring points on a needle of height and width at each [1] was preferred to the more often used half cylinder [17]. A PP-SYSTEMS narrow leaf cuvette was used with a single pair of needles suspended from end to end (45 mm).…”

Cloud response to summer temperatures in Fennoscandia over the last thousand years

“…At Laanila summer temperatures are too high for this latter mechanism to be important (Luoma 1997) and experimentation with Pinus sylvestris in eastern Finnish Lapland confirms that growing-season sunlight, not leaf temperature, explains 90% of photosynthetic rate variations (Hari et al, 1981).…”