Stem increment and hydraulic architecture of a boreal conifer (Larix sibirica) under contrasting macroclimates

作者：Chenlemuge Tselmeg; Schuldt Bernhard; Dulamsuren Choimaa; Hertel Dietrich; Leuschner Christoph; Hauck Markus^*

来源：Trees - Structure and Function, 2015, 29(3): 623-636.

DOI：10.1007/s00468-014-1131-x

• Hydraulic conductivity
• Wood anatomy
• Xylem anatomical plasticity
• Precipitation
• Drought adaptation

Key message Hydraulic conductivity and wood anatomical traits in Larix sibirica are correlated with macroclimate, and growing season precipitation in particular, along a precipitation gradient of 700 mm year(-1).
Empirical (K-s) and theoretical (K-p) sapwood area-specific hydraulic conductivity, hydraulically weighted (d(h)) and simple (d) tracheid diameters as well as tracheid density (TD) in roots, stems, and branches were studied in Larix sibirica trees, the dominant conifer at the southern, drought-affected range limit of the boreal forest in Inner Asia. We compared the hydraulic architecture of L. sibirica in two stands in Mongolia to larch trees grown in Central Europe under moist conditions and related hydraulics to macroclimate (precipitation, temperature) and productivity (basal area increment, BAI). K-s, K-p, d(h), and d correlated positively, and TD negatively with precipitation, temperature, and also BAI. Mean growing season precipitation (MGSP) seemed to affect the hydraulic traits more than temperature. A meta-analysis covering data of 14 conifer species from the northern hemisphere revealed a general relationship between MGSP and hydraulic traits. In contrast to expectation, K-p and d(h) did not show a steady decline from roots through the stem to branches in L. sibirica, but were of similar size or larger in the stem. Our results suggest that considerable plasticity in the hydraulic architecture is an important element of the drought adaptation of L. sibirica. It combines with drought-induced fine root abscission (as reported from earlier work) which may help to protect larger roots and the stem from cavitation.

• 出版日期2015-6