Submitted to: American Society of Plant Physiologists Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 12, 1999
Publication Date: N/A
Technical Abstract: Several lines of genetic and physiological evidence suggest that there may be more than one gene conferring aluminum (Al) tolerance to the wheat cultivar Atlas 66. Al-tolerant near-isogenic lines (NILs) of the Al-sensitive wheat cultivars 'Chisholm' and 'Century' have been developed through backcrossing with Atlas 66. Seedling Al toxicity curves (based on Al inhibition of root growth) for each parental cultivar and the Al-tolerant NILs were generated using a wide range of Al levels. They revealed that the Al-tolerant Century and Chisholm NILs exhibit significantly less Al tolerance than Atlas 66. This finding either supports the existence of more than one Al tolerance gene in Atlas 66, or indicates the presence of genes in the Century and Chisholm genomes that repress the action of Al tolerance genes from Atlas 66. The physiological basis of the incomplete transfer of Al tolerance to the Al-tolerant Century yand Chisholm NILs is being examined. In particular, the release of both malate and phosphate, compounds that are exuded from the root tips of Atlas 66 and which have each been postulated to contribute some degree of Al tolerance to Atlas 66, is being measured. These measurements will determine if malate or phosphate is being released from the root tips of the NILs, and if so, whether quantitative alterations in their exudation rates are observed relative to those of Atlas 66. Results of these studies will be presented from the standpoint of providing insight into the interrelationship between Al tolerance genes and physiological mechanisms in crop plants.