Intraspecific variation in morphological traits of root branch orders in Chamaecyparis obtusa
We aimed to clarify the intraspecific variation in the morphological traits of branch orders under different soil conditions in Chamaecyparis obtusa (Siebold & Zucc.) Endl.
We investigated the morphological traits of branch orders, based on 16,351 individual roots that were dissected from 12 intact fine root systems, up to a diameter of 2 mm at three C. obtusa stands. We also measured the concentrations of soil carbon, nitrogen, and inorganic nitrogen.
The intact fine root systems up to the diameter of 2 mm had branched into between five and seven orders. The diameter of first- to fourth-order roots and the lengths of second- and third-order roots were significantly different among the three stands. The morphological traits of lower order (first to third) roots correlated with soil inorganic nitrogen concentrations, but higher order (fourth to sixth) roots correlated with soil carbon concentrations.
We clarified the possible ranges of intraspecific variation in the morphological traits of root branch orders within C. obtusa. Both the lower and higher orders of the intact fine root systems were tightly related to the surrounding soil conditions.
KeywordsAbsorptive roots Fine roots Individual roots Root diameter Specific root length
Acid buffering capacity
Net primary productivity
Specific root length
We appreciate the editor and three reviewers for positive and critical suggestions and K. Noguchi (Forestry and Forest Product Research Institute, FFPRI) for reading the first draft of manuscript and giving invaluable comments. We thank M. Takano, Y. Yamaguchi, C. Tokoro (Nagoya University), T. Okamoto, T. Mizoguchi (FFPRI) for their invaluable suggestions and assistance with field work and laboratory analyses. We also thank S. Suzuki (Okazaki municipal office), T. Kadoya (Aichi Prefectural Forestry Institute), H. Fukumoto (The Mie Prefectural Forestry Research Center), T. Hakamata (Shizuoka Prefectural Research Institute of Agriculture and Forestry), and the Tenryuu District Forest Office for permission to use the forest health-monitoring survey sites of the Forestry Agency of Japan. This study was partly funded by JSPS KAKENHI Grant number 15H04519.
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