Dual purpose secondary compounds: phytotoxin of Centaurea diffusa also facilitates nutrient uptake.
Traits that allow more efficient foraging for a deficient resource could increase the competitiveness of a species in resource-poor habitats. Considering the metal-nutrient mobilization ability of many allelochemicals, it is hypothesized that, along with the reported toxic effect on the neighbors, these compounds could be directly involved in resource acquisition by the allelopathic plant. Using nutrient manipulation treatments in hydroponic culture, this hypothesis was tested using Centaurea diffusa, an invasive species that produces the putative phytotoxin 8-hydroxyquinoline (8HQ). The exudation of 8HQ by C. diffusa was very limited and transient. It was further shown that: C. diffusa utilizes 8HQ for its own acquisition of iron, a nutrient deficient in many of its alkaline, invaded habitats; there possibly exists a unique mechanism for the uptake of the 8HQ-complexed iron (Fe) in C. diffusa, which is novel to the nongraminaceous species; although phytotoxic at very low concentrations, the toxic effect of 8HQ showed a conditional response in the presence of metals, and was significantly reduced when 8HQ was complexed with copper (Cu) and Fe. This study, in addition to elucidating one of the possible adaptive mechanisms conferring competitive advantage to C. diffusa, also outlines measures to negate the phytotoxicity of its putative allelochemical. The results indicate that the exudation of 8HQ by C. diffusa could be primarily for nutrient acquisition.
Tharayil
Nishanth
N
Plant, Soil, and Insect Sciences, University of Massachusetts, Amherst, MA 01003, USA;Biology Department, University of Massachusetts, Amherst, MA 01003, USA;School of Natural Science, Hampshire College, Amherst, MA 01002, USA;Present address: Entomology, Soils & Plant Sciences, Clemson University, Clemson SC 29634, USA.
Bhowmik
Prasanta
P
Plant, Soil, and Insect Sciences, University of Massachusetts, Amherst, MA 01003, USA;Biology Department, University of Massachusetts, Amherst, MA 01003, USA;School of Natural Science, Hampshire College, Amherst, MA 01002, USA;Present address: Entomology, Soils & Plant Sciences, Clemson University, Clemson SC 29634, USA.
Alpert
Peter
P
Plant, Soil, and Insect Sciences, University of Massachusetts, Amherst, MA 01003, USA;Biology Department, University of Massachusetts, Amherst, MA 01003, USA;School of Natural Science, Hampshire College, Amherst, MA 01002, USA;Present address: Entomology, Soils & Plant Sciences, Clemson University, Clemson SC 29634, USA.
Walker
Elsbeth
E
Plant, Soil, and Insect Sciences, University of Massachusetts, Amherst, MA 01003, USA;Biology Department, University of Massachusetts, Amherst, MA 01003, USA;School of Natural Science, Hampshire College, Amherst, MA 01002, USA;Present address: Entomology, Soils & Plant Sciences, Clemson University, Clemson SC 29634, USA.
Amarasiriwardena
Dulasiri
D
Plant, Soil, and Insect Sciences, University of Massachusetts, Amherst, MA 01003, USA;Biology Department, University of Massachusetts, Amherst, MA 01003, USA;School of Natural Science, Hampshire College, Amherst, MA 01002, USA;Present address: Entomology, Soils & Plant Sciences, Clemson University, Clemson SC 29634, USA.
Xing
Baoshan
B
Plant, Soil, and Insect Sciences, University of Massachusetts, Amherst, MA 01003, USA;Biology Department, University of Massachusetts, Amherst, MA 01003, USA;School of Natural Science, Hampshire College, Amherst, MA 01002, USA;Present address: Entomology, Soils & Plant Sciences, Clemson University, Clemson SC 29634, USA.
D000222:Adaptation, Physiological; D001692:Biological Transport / Q000502:physiology; D031179:Centaurea / Q000378:metabolism*; D006912:Hydroxyquinolines / Q000378:metabolism*; D000090463:Iron Deficiencies; D010758:Phosphorus / Q000172:deficiency; D018517:Plant Roots / Q000378:metabolism; D014118:Toxins, Biological / Q000493:pharmacokinetics*
D006912:Hydroxyquinolines; D014118:Toxins, Biological; D010758:Phosphorus