Autotoxicity of root exudates varies with species identity and soil phosphorus

• Published in: Ecotoxicology (London) Vol. 28; no. 4; pp. 429 - 434
• Main Authors: Sun, Zhen-Kai, He, Wei-Ming
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.05.2019; Springer; Springer Nature B.V
• Subjects: Activated carbon; Biological Availability; Biomass; Carbon content; Earth and Environmental Science; Ecology; Ecotoxicology; Environment; Environmental Management; Environmental Monitoring; Exudates; Exudates and Transudates - chemistry; Exudation; Lactuca - drug effects; Lactuca - metabolism; Phosphorus; Phosphorus - metabolism; Phosphorus content; Plant biomass; Plant communities; Plant Roots - chemistry; Plant Roots - metabolism; Plant species; Ratios; root exudates; Roots; Sesbania - drug effects; Sesbania - metabolism; Sesbania cannabina; Shoots; Soil; Soil Pollutants - metabolism; Soils; Solidago - drug effects; Solidago - metabolism; Solidago canadensis; Species; Stoichiometry; toxicity; Competition; Stoichiometry; Plant species identity; Root exudate autotoxicity; Soil P availability
• ISSN: 0963-9292; 1573-3017; 1573-3017
• DOI: 10.1007/s10646-019-02035-z

Root exudate autotoxicity (i.e. root exudates from a given plant have toxic effects on itself) has been recognized to be widespread. Here we examined how plant species identity and soil phosphorus (P) availability influenced this autotoxicity and the possible stoichiometric mechanisms. We conducted an experiment with three species ( Luctuca sativa , Sesbania cannabina , and Solidago canadensis ), which were subject to four treatments consisting of activated carbon (AC) and soil P. AC addition increased the whole-plant biomass of each species under high P conditions and this AC effect varied strongly with species identity. For Solidago , the relative increase in whole-plant biomass due to AC addition was larger in the low P than in the high P. Root exudate autotoxicity differed between roots and shoots. AC addition decreased root N:P ratios but failed to influence shoot N:P ratios in three species. These findings suggest that soil P enrichment might mediate root exudate autotoxicity and that this P-mediated autotoxicity might be related to root N and P stoichiometry. These patterns and their implications need to be addressed in the context of plant communities. Highlights Root exudate autotoxicity varied with species identity and soil P. Root exudate autotoxicity differed between roots and shoots. P-mediated autotoxicity might be related to N:P ratios.