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Growth and uptake of Cd and Zn by Leucaena leucocephala in reclaimed soils as affected by NaCl salinity
Author(s) -
Helal H. Mohamed,
Upenov Aibek,
Issa Ghada J.
Publication year - 1999
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/(sici)1522-2624(199912)162:6<589::aid-jpln589>3.0.co;2-1
Subject(s) - chemistry , leucaena leucocephala , soil water , salinity , soil salinity , irrigation , agronomy , environmental chemistry , bioavailability , zinc , gypsum , manure , biology , ecology , organic chemistry , bioinformatics , paleontology
Heavy metal accumulation in reclaimed soils is increasing rapidly in developing countries where the use of saline waters for irrigation is a common practice, even though salinity‐heavy metal interactions are not fully understood. An example for this development is the Bangar area of Egypt where the application of contaminated amendments during the last 30 years has increased the Cd and Zn concentrations in topsoils from 0.08 to 0.76 mg · kg —1 and from 17 to 73 mg · kg —1 respectively. This work aimed at evaluating the uptake of Cd and Zn by Leucaena leucocephala , a leguminous tree cropped for fodder and green manure, as affected by the addition of 10 mM NaCl to irrigation water. During a 6 month field experiment, salinized and control plots were compared with respect to soil solution composition and root development as well as the uptake of Cd and Zn and their translocation to the leaves. NaCl treatment raised the concentration of organic carbon, Cd and Zn in soil solution and enhanced the uptake of Cd and Zn significantly. Salinized plants showed shorter roots, reduced retention of Cd and Zn in roots and stems and considerable translocation of both elements to the leaves. This work demonstrates that NaCl salinity affects not only the bioavailability of soil Cd and Zn but also modifies plant functions related to their acquisition and translocation to the leaves. The results provide evidence that the risk of transfer of heavy metals to the food chain and their leachability to the ground water may be greater under saline conditions than generally assumed.