Chin J Plant Ecol ›› 2011, Vol. 35 ›› Issue (12): 1226-1235.DOI: 10.3724/SP.J.1258.2011.01226

• Research Articles • Previous Articles     Next Articles

Genetic variation in root architecture and phosphorus efficiency in response to heterogeneous phosphorus deficiency in Pinus massoniana families

YANG Qing1, ZHANG Yi1, ZHOU Zhi-Chun1,*(), MA Xue-Hong1, LIU Wei-Hong2, FENG Zhong-Ping2   

  1. 1Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Fuyang, Zhejiang 311402, China
    2Laoshan Forest Farm of Chun’an County of Zhejiang Province, Chun’an, Zhejiang 311700, China
  • Received:2011-06-21 Accepted:2011-09-22 Online:2011-06-21 Published:2011-12-15
  • Contact: ZHOU Zhi-Chun

Abstract:

Aims Our aim was to investigate the genotypic variations among semi-sib families of Pinus massoniana for adaptive changes in root morphology and architecture in response to different types of low soil phosphorus (P) availability and their relationships to plant growth and P efficiency.
Methods Pot experiments were conducted during the 2010 growing season in a nursery located in Chun’an County of Zhejiang Province, China. Seven semi-sib families ofP. massoniana contrasting in root architecture and P efficiency were compared for their root morphological and architectural traits and their relationships to plant growth and P efficiency under both heterogeneous and homogeneous low P conditions.
Important findings Large genotypic variations were observed under different types of low-P conditions. The adaptive mechanism for P deficiency was different under heterogeneous and homogeneous low-P conditions. Under homogeneous low-P conditions, adaptive responses of root growth parameters were present in genotypes with high-P efficiency such as ‘3201’ and ‘1217’, while it was not observed in genotypes with low-P efficiency. Root architecture was not closely related to plant P efficiency under homogeneous low-P conditions. Under heterogeneous low-P conditions, root architecture was found to closely related to P efficiency. Genotypes with shallow root architecture had optimal root parameters including root length, surface area and biomass in the top layer of soil, thus having the greater ability for P absorption and having higher P efficiency and biomass. The heritability for the root biomass and the proportion of root in the top soil layer was 0.88 and 0.72, respectively. A significant interactive effect between patterns of low-P conditions and P efficiency was observed. Given that P. massonianahas great genetic potential for adaptation to low-P soils, the selection of high-P efficiency genotypes with optimal root architecture may significantly increase wood production of P. massoniana under low-P conditions.

Key words: Key words family, heterogeneous phosphorus deficiency, phosphorus efficiency, Pinus massoniana, root architecture