Root uptake of lipophilic zinc-rhamnolipid complexes.
This study investigated the formation and plant uptake of lipophilic metal-rhamnolipid complexes. Monorhamnosyl and dirhamnosyl rhamnolipids formed lipophilic complexes with copper (Cu), manganese (Mn), and zinc (Zn). Rhamnolipids significantly increased Zn absorption by Brassica napus var. Pinnacle roots in (65)Zn-spiked ice-cold solutions, compared with ZnSO4 alone. Therefore, rhamnolipid appeared to facilitate Zn absorption via a nonmetabolically mediated pathway. Synchrotron XRF and XAS showed that Zn was present in roots as Zn-phytate-like compounds when roots were treated with Zn-free solutions, ZnSO4, or Zn-EDTA. With rhamnolipid application, Zn was predominantly found in roots as the Zn-rhamnolipid complex. When applied to a calcareous soil, rhamnolipids increased dry matter production and Zn concentrations in durum (Triticum durum L. cv. Balcali-2000) and bread wheat (Triticum aestivum L. cv. BDME-10) shoots. Rhamnolipids either increased total plant uptake of Zn from the soil or increased Zn translocation by reducing the prevalence of insoluble Zn-phytate-like compounds in roots.
Stacey
Samuel P
SP
Soil and Land Systems, School of Earth and Environmental Sciences, The University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia. samuel.stacey@adelaide.edu.au
McLaughlin
Michael J
MJ
Cakmak
Ismail
I
Hettiarachchi
Ganga M
GM
Scheckel
Kirk G
KG
Karkkainen
Michael
M
D000042:Absorption; D029688:Brassica napus / Q000378:metabolism; D006017:Glycolipids / Q000008:administration & dosage / Q000378:metabolism*; D007700:Kinetics; D018517:Plant Roots / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D010944:Plants / Q000378:metabolism*; D012987:Soil / Q000032:analysis; D013057:Spectrum Analysis; D014908:Triticum / Q000378:metabolism; D015032:Zinc / Q000032:analysis / Q000378:metabolism*
D006017:Glycolipids; D012987:Soil; C418382:rhamnolipid; D015032:Zinc