Root growth and root system architecture of field-grown maize in response to high planting density
This paper aims to investigate the adaptation of maize root system architecture (RSA) in response to increasing planting densities.
A three-year field study was conducted with three planting densities (40,000, 70,000, and 90,000 plants per ha, which are abbreviated as D40000, D70000 and D90000, respectively). The dynamic change of root morphological traits and the 3-dimensional RSA were quantified.
The grain yield per ha increased with increasing plant density from D40000 to D70000, and then decreased at D90000. Compared to D70000, high planting density of D90000 did not changed the total root biomass per ha but increased shoot biomass per ha by 4 to 8% in two of the three experimental years. Grain yield per plant and plant NPK concentration decreased with increasing planting density. Total accumulation of P and K per ha also decreased at D90000 compared to D70000. Root to shoot ratio was reduced at high planting density beginning 50 days after emergence. Compared to the control (D70000), total root length (TRL) per plant was reduced by 18 to 30% at D90000 and increased by 43 to 56% at D40000, root biomass per plant was reduced by 23 to 34% at D90000 and increased by 66 to 75% at D40000. High plant density reduced the number of nodal roots, lateral root density (LRD) and the average lateral root (LR) length, but with less effect on the length of axial roots. The RSA is characteristic of “intra-row contraction and inter-row extension”. Vertically, root growth in top soil layer (0- to 36- cm) was enhanced under supra-optimal plant density, but had a negligible effect in deep soil layers (36- to 60- cm).
To adapt to the limited photosynthesis capacity in the roots under high planting density, maize plants tend to reduce nodal root number and inhibit lateral root growth. They maintain nodal root length to explore a larger soil space, and adjust root growth in the intra-row and inter-row direction to avoid root-to-root competition.
KeywordsInter-row Intra-row Root system architecture Competition Plant density Maize
40,000 plants per ha
70,000 plants per ha
90,000 plants per ha
total root length
lateral root density
specific root length
root length density
This work was financially supported by National Basic Research Program (973 Program) of China (2015CB150402) and State key research program (2016YFD0300304).
- Böhm W (1979) Methods of studying root systems. Ecological studies, 33. Springer, Berlin, pp 20–25Google Scholar
- Chen YL et al (2012b) Root growth and its response to increasing planting density in differentmaize hybrids. Plant Nutrition and Fertilizer Science 18(1):52–59 in ChineseGoogle Scholar
- File, A. L., Murphy, G. P., & Dudley, S. A. (2012). Fitness consequences of plants growing with siblings: reconciling kin selection, niche partitioning and competitive ability. Paper presented at the Proc. R. Soc. BGoogle Scholar
- Guingo E, Hébert Y (1997) Relationship between mechanical resistance of the maize root system and root morphology, and their genotypic and environmental variation. Maydica 42(3):265–274Google Scholar
- Hebert Y, et al (1992) Root lodging resistance in forage maize. Genetic variability of root system and aerial part. Maydica (Italy)Google Scholar
- Liu S et al (2012) Effect of planting density on root lodging resistance and its relationship to nodal root growth characteristics in maize (Zea mays L.). J Agric Sci 4(12):182Google Scholar
- Lynch J, Brown K (1998) Regulation of root architecture by phosphorus availability. Current Topics Plant Physiol 19:148–156Google Scholar
- Lynch, J.P., Chimungu, J.G. and Brown, K.M. (2014) Root anatomical phenes associated with water acquisition from drying soil: targets for crop improvement. J Exp Bot 65(21):6155–6166Google Scholar
- Marler TE (2013) Kin recognition alters root and whole plant growth of split-root Cycas edentata seedlings. HortScience 48(10):1266–1269Google Scholar
- Pellerin S, Demotes-Mainard S, Kutschera L (1992) Effect of competition for light between plants on the root shoot ratio and the number of adventitious roots of maize. In Proc 3:65–68Google Scholar
- Sanguineti M et al (1998) Root and shoot traits of maize inbred lines grown in the field and in hydroponic culture and their relationships with root lodging. Maydica 43:211–216Google Scholar
- Soil Survey Staff (1998) Keys to Soil Taxonomy. United States Department of Agriculture, Natural Resources Conservation Service, Washington, DC, USA, pp. 211Google Scholar
- Soon Y K, Kalra Y P. A. (1995) comparison of plant tissue digestion methods for nitrogen and phosphorus analyses [J]. Can J Soil Sci, 75(2): 243–245Google Scholar
- Yu DW (2014) Study on the effect of brace root traits on lodging resistance and genetic research of maize brace root traits.[D]. North West Agriculture and Forestry University, Yangling (in Chinese)Google Scholar
- Zhang R et al (2015) Effect of subsoiling on root morphological and physiological characteristics of spring maize. transactions of the Chinese society of. Agric Eng 31(5):78–84Google Scholar