Concentrations of metals and potential metal-binding compounds and speciation of Cd, Zn and Cu in phloem and xylem saps from castor bean plants (Ricinus communis) treated with four levels of cadmium

Kenji Hazama, Shinji Nagata, Tamaki Fujimori, Shuichi Yanagisawa, Tadakatsu Yoneyama
Physiologia Plantarum 2015, 154 (2): 243-55
We examined the concentrations of metals (Cd, Zn, Cu, Fe and Mn) and potential metal-binding compounds [nicotianamine (NA), thiol compounds and citrate] in xylem and phloem saps from 4-week-old castor bean plants (Ricinus communis) treated with 0 (control), 0.1, 1.0, and 10 μM Cd for 3 weeks. Treatment with 0.1 and 1 μM Cd produced no visible damage, while 10 μM Cd retarded growth. Cadmium concentrations in both saps were higher than those in the culture solution at 0.1 μM, similar at 1.0 μM and lower at 10 μM. Cd at 10 μM reduced Cu and Fe concentrations in both saps. NA concentrations measured by capillary electrophoresis-mass spectrometry (MS) in xylem sap (20 μM) were higher than the Cu concentrations, and those in phloem sap (150 μM) were higher than those of Zn, Fe and Cu combined. Reduced glutathione concentrations differed in xylem and phloem saps (1-2 and 30-150 μM, respectively), but oxidized glutathione concentrations were similar. Phloem sap phytochelatin 2 concentration increased from 0.8 μM in controls to 8 μM in 10 μM Cd. Free citrate was 2-4 μM in xylem sap and 70-100 μM in phloem sap. Total bound forms of Cd in phloem and xylem saps from 1 μM Cd-treated plants were 54 and 8%, respectively. Treatment of phloem sap with proteinaseK reduced high-molecular compounds while increasing fractions of low-molecular Cd-thiol complexes. Zinc-NA, Fe-NA and Cu-NA were identified in the phloem sap fraction of control plants by electrospray ionization time-of-flight MS, and the xylem sap contained Cu-NA.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"