Density-dependent root morphology and root distribution in the submerged plant Vallisneria natans

• Published in: Environmental and experimental botany Vol. 57; no. 1; pp. 195 - 200
• Main Authors: Xie, Yonghong, An, Shuqing, Wu, Bofeng, Wang, Wenwen
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.08.2006; Elsevier Science
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; clay soils; diameter; dry matter partitioning; Economic plant physiology; Fundamental and applied biological sciences. Psychology; macrophytes; Morphological plasticity; nitrogen; Nutrient; nutrient availability; nutrient content; phosphorus; plant competition; plant density; plant morphology; plant nutrition; Root distribution; Root foraging; root systems; roots; sandy loam soils; spatial distribution; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); Vallisneria; Vallisneria natans; Morphological plasticity; Root distribution; Nutrient; Root foraging; Vallisneria natans; Root; Morphology; Biomass; Depth
• ISSN: 0098-8472; 1873-7307
• DOI: 10.1016/j.envexpbot.2005.06.001

Root morphology, root distribution and biomass allocation in relation to plant nutrient concentration were investigated in the submerged macrophyte Vallisneria natans, growing on two types of sediment (clay and a mixture of sandy loam and clay) with three kinds of initial density (290, 650 and 1300 plants m −2). Both initial density and sediment type had significant impacts on biomass accumulation, root morphology, root distribution, and plant N and P concentrations, whereas biomass allocation was affected by sediment type alone, rather than plant density. For the same sediment type, biomass of the individual was highest in 290 plants m −2, intermediate in 650 plants m −2 and lowest in 1300 plants m −2. When initial density increased from 290 to 1300 plants m −2, root diameter decreased from 0.36 to 0.31 mm in the mixed sediment and from 0.43 to 0.35 mm in clay, but specific root length increased from 3.3 to 5.9 m g −1 in the mixed sediment and from 3.0 to 4.6 m g −1 in clay. For the plants grown in the mixed sediment, root distribution ratio in 4–8 cm depth increased from 3.3 to 30.8% when initial density increased from 290 to 1300 plants m −2. Increase of density led to decreased plant N and P concentrations. It is concluded that plasticity in root morphology and root distribution exists in V. natans as a response to density, and can help to adapt to competitive environments by increasing efficiency of nutrient acquisition.