Long-distance transport of cadmium from roots to leaves of Solanum melongena
- 428 Downloads
In this study, the characteristics of cadmium (Cd) uptake by roots and translocation from roots to leaves of two eggplant species (Solanum melongena and Solanum torvum) under relatively low Cd concentrations were investigated using stable 108Cd isotope through a number of hydroponic experiments. The uptake and translocation of 108Cd was compared with those of 70Zn and 15N. The results showed more 108Cd was loaded to the vascular channels and translocated upward to the leaves in S. melongena than in S. torvum, while the 108Cd concentrations were significantly lower in the roots of S. melongena than in S. torvum. When the phloem and xylem were wounded by grafting treatments, the foliar 108Cd concentrations were decreased by more than 66 % regardless of the rootstock species, whereas the uptake of 108Cd in the root was not inhibited by grafting. Similar grafting effects were observed for 70Zn. Hence, wounding phloem and xylem by grafting disturbed the upward transport of 108Cd and 70Zn to the eggplant leaves. Similarly, interruption of the phloem by the girdling treatment reduced the concentrations of 108Cd in the leaves of S. melongena by approximately 51 %, though the uptake of 108Cd by roots was not reduced by the interruption of phloem. In contrast, neither 70Zn concentrations nor stable N isotope ratio (δ15N) values in the roots and leaves of S. melongena were significantly influenced by the interruption of phloem. In conclusion, the phloem played a dominant role in the long-distance transport of Cd from the root to the leaf of S. melongena, whereas the xylem was the main channel for the translocation of Zn and N.
KeywordsEggplant (Solanum melongena) Grafting Girdling Heavy metals Phloem Transport
This research work was financially supported by the National Science & Technology Support Program of China (Grant Number: 2012BAC13B03) and the strategic priority research program of the Chinese Academy of Science (Grant Number: XDB14020204).
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
- Costa G, Morel JL (1994) Water relations, gas exchange and amino acid content in Cd-treated lettuce. Plant Physio Bioch 32:561–570Google Scholar
- Gisbert C, Prohens J, Raigón MD, Stommel JR, Nuez F (2011) Eggplant relatives as sources of variation for developing new rootstocks: effects of grafting on eggplant yield and fruit apparent quality and composition. Sci Hortic-Amsterdam 128:14–22. doi: 10.1016/j.scienta.2010.12.007 CrossRefGoogle Scholar
- Hoagland DR, Arnon DI (1950) The water-culture method for growing plants without soil. Circular. Califronia Agricultural Experimental Station, University of California, BerkeleyGoogle Scholar
- Kawaguchi M, Taji A, Backhouse D, Oda M (2008) Anatomy and physiology of graft incompatibility in solanaceous plants. J Hortic Sci Biotechnol 83:581–588Google Scholar
- Krüger C, Hell R, Stephan UW (2001) A metal-binding LEA protein trafficks micronutrients in the phloem of Ricinus communis L. In: Horst WJ et al (eds) Plant nutrition-food security and sustainability of agro-ecosystems. Kluwer Academic Publisher, Netherlands, pp 194–195Google Scholar
- Popelka JC, Schubert S, Schulz R, Hansen AP (1996) Cadmium uptake and translocation during reproductive development of peanut (Arachis hypogaea L.). J Appl Bot-Angew Bot 70:140–143Google Scholar
- Rafiq MT, Aziz R, Yang X, Xiao W, Rafiq MK, Ali B, Li T (2014) Cadmium phytoavailability to rice (Oryza sativa L.) grown in representative Chinese soils. A model to improve soil environmental quality guidelines for food safety. Ecotox Environ Safe 103:101–107. doi: 10.1016/j.ecoenv.2013.10.016 CrossRefGoogle Scholar
- Salt DE, Prince RC, Pickering IJ, Raskin I (1995) Mechanisms of cadmium mobility and accumulation in Indian mustard. Plant Physiol 109:1427–1433Google Scholar