A novel Brassica-rhizotron system to unravel the dynamic changes in root system architecture of oilseed rape under phosphorus deficiency.
An important adaptation of plants to phosphorus (P) deficiency is to alter root system architecture (RSA) to increase P acquisition from the soil, but soil-based observations of RSA are technically challenging, especially in mature plants. The aim of this study was to investigate the root development and RSA of oilseed rape (Brassica napus L.) under low and high soil P conditions during an entire growth cycle.



A new large Brassica-rhizotron system (approx. 118-litre volume) was developed to study the RSA dynamics of B. napus 'Zhongshuang11' in soils, using top-soils supplemented with low P (LP) or high P (HP) for a full plant growth period. Total root length (TRL), root tip number (RTN), root length density (RLD), biomass and seed yield traits were measured.



TRL and RTN increased more rapidly in HP than LP plants from seedling to flowering stages. Both traits declined from flowering to silique stages, and then increased slightly in HP plants; in contrast, root senescence was observed in LP plants. RSA parameters measured from the polycarbonate plates were empirically consistent with analyses of excavated roots. Seed yield and shoot dry weights were closely associated positively with root dry weights, TRL, RLD and RTN at both HP and LP.



The Brassica-rhizotron system is an effective method for soil-based root phenotyping across an entire growth cycle. Given that root senescence is likely to occur earlier under low P conditions, crop P deficiency is likely to affect late water and nitrogen uptake, which is critical for efficient resource use and optimal crop yields.
National Key Lab of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, PR China Key Lab of Cultivated Land Conservation, Ministry of Agriculture/Microelement Research Centre, Huazhong Agricultural University, Wuhan 430070, PR China.
Pan
P
Yuan
National Key Lab of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, PR China Key Lab of Cultivated Land Conservation, Ministry of Agriculture/Microelement Research Centre, Huazhong Agricultural University, Wuhan 430070, PR China.
Guang-Da
GD
Ding
Key Lab of Cultivated Land Conservation, Ministry of Agriculture/Microelement Research Centre, Huazhong Agricultural University, Wuhan 430070, PR China.
Hong-Mei
HM
Cai
National Key Lab of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, PR China Key Lab of Cultivated Land Conservation, Ministry of Agriculture/Microelement Research Centre, Huazhong Agricultural University, Wuhan 430070, PR China.
Ke-Mo
KM
Jin
Plant and Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK.
Martin Roger
MR
Broadley
National Key Lab of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, PR China Key Lab of Cultivated Land Conservation, Ministry of Agriculture/Microelement Research Centre, Huazhong Agricultural University, Wuhan 430070, PR China.
Fang-Sen
FS
Xu
National Key Lab of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, PR China Key Lab of Cultivated Land Conservation, Ministry of Agriculture/Microelement Research Centre, Huazhong Agricultural University, Wuhan 430070, PR China leish@mail.hzau.edu.cn.
Lei
L
Shi
D018533:Biomass; D029688:Brassica napus / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D009584:Nitrogen / Q000378:metabolism; D010641:Phenotype; D010758:Phosphorus / Q000172:deficiency*; D018517:Plant Roots / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D018520:Plant Shoots / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D036226:Seedlings / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D012639:Seeds / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D012987:Soil / Q000737:chemistry
D012987:Soil; D010758:Phosphorus; D009584:Nitrogen
Brassica–rhizotron; Oilseed rape (Brassica napus L.); dynamic changes; phosphorus deficiency; root system architecture