|Hart, Jon - CORNELL UNIVERSITY|
Submitted to: American Society of Plant Physiologists Meeting
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 1998
Publication Date: N/A
Technical Abstract: The accumulation of excessive amounts of cadmium (Cd) in durum wheat grown in high-Cd soils of the Great Plains of North America represents a potential threat to the export market for durum wheat. The physiological processes that result in high Cd accumulation in mature grains are not well understood. However, a genetic marker associated with low Cd accumulation in durum wheat has been identified. This study employed two nearly isogenic durum wheat cultivars developed using these markers. Plants grown in low levels of Cd in solution culture in a growth chamber were used to study Cd distribution among plant organs at various stages of growth. Approximately three-fold higher amounts of Cd were observed in the high Cd-accumulation line compared with the low Cd-accumulation line throughout its growth cycle. Other studies used 109Cd to measure root Cd2+ influx and binding of Cd2+ as well as translocation of Cd from roots to shoots in seedlings of the two cultivars. Concentration- dependent root uptake measurements demonstrated that Cd2+ influx occurs via a saturable process similar to that previously measured in other durum wheat cultivars as well as in bread wheat cultivars. The kinetic constants for Cd2+ uptake were not different in the two cultivars, suggesting that the gene(s) associate with Cd accumulation did not affect root Cd2+ influx. Similarly, differences were not detected between the two lines in Cd binding to cell walls. In contrast, rates of Cd movement from root to shoot were greater in the high Cd-accumulating cultivar, suggesting that the Cd-accumulation gene may affect Cd translocation and the ultimate accumulation of Cd in durum wheat grain.