title: Seasonal variation in chemistry, but not morphology, in roots of Quercus robur growing in different soil types.
abstract: Patterns of root traits among different root orders and their variation across seasons are of considerable importance for soil resource acquisition and partitioning in forest ecosystems. We evaluated whether morphological, anatomical and biochemical traits varied among root orders of Quercus robur (L.) sampled across spring, summer and fall seasons and growing in two different soil types with contrasting site fertility. We found no consistent differences in root diameter and specific root length in relation to soil type or growing season. There was, however, a strong seasonal variation in patterns of nitrogen (N) concentration among root orders. During spring and summer, N concentration was highest in the most distal, absorptive portion of the root system. At the end of the growing season, we observed a sharp decline in the N concentration of these lower-order, absorptive roots and an increase in N concentration of the higher-order, transport roots. The specific mechanisms driving the seasonally changing N concentration remain unclear but are likely related to different functions of lower-order roots for absorption and higher-order roots for structure and storage. Future work should identify how common the observed seasonal changes in N concentration are across species and determine what specific environmental cues plants or roots use to trigger shifts in resource allocation within the root branching hierarchy.
authors: Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland zadworny@man.poznan.pl.
authors: Marcin
authors: M
authors: Zadworny
authors: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
authors: M Luke
authors: ML
authors: McCormack
authors: Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland.
authors: Katarzyna
authors: K
authors: Rawlik
authors: Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland Department of Game Management and Forest Protection, Faculty of Forestry, Poznań University of Life Sciences, Wojska Polskiego 71c, 60-625 Poznań, Poland.
authors: Andrzej M
authors: AM
authors: Jagodziński
mesh_terms: D000704:Analysis of Variance; D002244:Carbon / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen / Q000032:analysis; D018517:Plant Roots / Q000033:anatomy & histology*; D011044:Poland; D029963:Quercus / Q000033:anatomy & histology* / Q000254:growth & development*; D012621:Seasons; D012987:Soil / Q000737:chemistry*; D012995:Solubility; D013213:Starch / Q000032:analysis; D013997:Time Factors
chemical_list: D012987:Soil; D002244:Carbon; D013213:Starch; D009584:Nitrogen
keywords: nitrogen reserve; oak forest; root order diversity; seasonal variation; storage