title: Quantitative Classification of Rice (Oryza sativa L.) Root Length and Diameter Using Image Analysis.
abstract: Quantitative study of root morphological characteristics of plants is helpful for understanding the relationships between their morphology and function. However, few studies and little detailed and accurate information of root characteristics were reported in fine-rooted plants like rice (Oryza sativa L.). The aims of this study were to quantitatively classify fine lateral roots (FLRs), thick lateral roots (TLRs), and nodal roots (NRs) and analyze their dynamics of mean diameter (MD), lengths and surface area percentage with growth stages in rice plant. Pot experiments were carried out during three years with three rice cultivars, three nitrogen (N) rates and three water regimes. In cultivar experiment, among the three cultivars, root length of 'Yangdao 6' was longest, while the MD of its FLR was the smallest, and the mean diameters for TLR and NR were the largest, the surface area percentage (SAP) of TLRs (SAPT) was the highest, indicating that Yangdao 6 has better nitrogen and water uptake ability. High N rate increased the length of different types of roots and increased the MD of lateral roots, decreased the SAP of FLRs (SAPF) and TLRs, but increased the SAP of NRs (SAPN). Moderate decrease of water supply increased root length and diameter, water stress increased the SAPF and SAPT, but decreased SAPN. The quantitative results indicate that rice plant tends to increase lateral roots to get more surface area for nitrogen and water uptake when available assimilates are limiting under nitrogen and water stress environments.
authors.affiliation: National Engineering and Technology Center for Information Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, Jiangsu, P.R. China.
authors.forename: Dongxiang
authors.initials: D
authors.lastname: Gu
authors.affiliation: National Engineering and Technology Center for Information Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, Jiangsu, P.R. China.
authors.forename: Fengxian
authors.initials: F
authors.lastname: Zhen
authors.affiliation: Department of Crop & Soil Science, Oregon State University, Corvallis, Oregon, United States of America.
authors.forename: David B
authors.initials: DB
authors.lastname: Hannaway
authors.affiliation: National Engineering and Technology Center for Information Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, Jiangsu, P.R. China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: National Engineering and Technology Center for Information Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, Jiangsu, P.R. China.
authors.forename: Leilei
authors.initials: L
authors.lastname: Liu
authors.affiliation: National Engineering and Technology Center for Information Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, Jiangsu, P.R. China.
authors.forename: Weixing
authors.initials: W
authors.lastname: Cao
authors.affiliation: National Engineering and Technology Center for Information Agriculture, Jiangsu Key Laboratory for Information Agriculture, Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, Jiangsu, P.R. China.
authors.forename: Liang
authors.initials: L
authors.lastname: Tang
mesh_terms: D007091:Image Processing, Computer-Assisted; D012275:Oryza / Q000033:anatomy & histology* / Q000145:classification / Q000254:growth & development; D018517:Plant Roots / Q000033:anatomy & histology* / Q000145:classification / Q000254:growth & development