Mixed-power scaling of whole-plant respiration from seedlings to giant trees

• DOI: 10.1073/pnas.0902554107
• Publication Date: 2010-01-09T03:07:12Z
• Authors: Shigeta Mori; Keiko Yamaji; Atsushi Ishida; Stanislav G. Prok...; Oxana V. Masyagina; Akio Hagihara; A.T.M. Rafiqul Hoque; Rempei Suwa; Akira Osawa; Tomohiro Nishizono; Tatsushiro Ueda; Masaru Kinjo; Tsuyoshi Miyagi; Takuya Kajimoto; Takayoshi Koike; Yojiro Matsuura; Takeshi Toma; Olga A. Zyryanova; Anatoly P. Abaimov; Yoshio Awaya; Masatake G. Araki; Tatsuro Kawasaki; Yukihiro Chiba; Marjnah Umari
• Keywords: 0106 biological sciences; 2. Zero hunger; Seedlings; Botany; Plant Transpiration; Biomass; Gases; 15. Life on land; 01 natural sciences; Trees

The scaling of respiratory metabolism with body mass is one of the most pervasive phenomena in biology. Using a single allometric equation to characterize empirical scaling relationships and to evaluate alternative hypotheses about mechanisms has been controversial. We developed a method to directly measure respiration of 271 whole plants, spanning nine orders of magnitude in body mass, from small seedlings to large trees, and from tropical to boreal ecosystems. Our measurements include the roots, which have often been ignored. Rather than a single power-law relationship, our data are fit by a biphasic, mixed-power function. The allometric exponent varies continuously from 1 in the smallest plants to 3/4 in larger saplings and trees. Therefore, our findings support the recent findings of Reich et al. [Reich PB, Tjoelker MG, Machado JL, Oleksyn J (2006) Universal scaling of respiratory metabolism, size, and nitrogen in plants. Nature 439:457–461] and West, Brown, and Enquist [West GB, Brown JH, Enquist BJ (1997) A general model for the origin of allometric scaling laws in biology.Science276:122 -126.]. The transition from linear to 3/4-power scaling may indicate fundamental physical and physiological constraints on the allocation of plant biomass between photosynthetic and nonphotosynthetic organs over the course of ontogenetic plant growth.