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dc.contributor.advisorLangston, Ruble
dc.creatorSadik, Mohamed Kamal
dc.description.abstractIn an effort to relate the chemical com position of soil to the iron chlorosis problem in grain sorghum grown in some of the calcareous soils in Texas, samples were collected from soils that induced this malresponse and from others that did not. The soils were chemically analyzed and differences in some of the components were detected. However, the chemical analysis of the soil failed to point out one or few component(s) that could be considered as be [sic] main factor(s) in iron chlorosis. A greenhouse study, in which both normal and chlorosis-inducing soils were used, was conducted to study the influence of selected soil chemical properties on the composition of grain sorghum plants, and on the absorption and distribution of Fe⁵⁹ within the plant. The chemical analysis showed that shoots of the susceptible variety of grain sorghum were higher in K and Ca and lower in Mg and Fe than were those of the resistant variety. The shoots of the resistant variety tended to be slightly higher in both Na and P than were the susceptible ones. The roots, on the other hand, behaved somewhat differently than did the shoots. The concentration of K and P were significantly higher in the roots of the susceptible variety and were lower in Ca and Fe than were the roots of the resistant variety. The chlorotic soil was found to produce plants higher in K, Ca, Mg and P as compared to the normal soils. Some correlations were found between chemical composition of the plants and certain chemical soil properties. In an effort to elucidate the role of phosphate, bicarbonate and potassium ions as factors contributing to iron chlorosis, a suspension culture with resins was conducted. All nutrients for the grain sorghum plants were supplied in an exchangeable form. The influence of these three ions on the absorption of iron was traced with Fe⁵⁹. Increasing the level of phosphorus in the culture media was accompanied by an increase in both phosphorus and Fe⁵⁹ in the shoots and roots of the plant. Potassium in the media tended to decrease the iron content of the plants but did not affect the phosphorus. Increasing bicarbonate level in the culture media decreased drastically both the iron and phosphorus contents of roots and shoots.en
dc.format.extent120 leavesen
dc.rightsThis thesis was part of a retrospective digitization project authorized by the Texas A&M University Libraries. Copyright remains vested with the author(s). It is the user's responsibility to secure permission from the copyright holder(s) for re-use of the work beyond the provision of Fair Use.en
dc.subjectMajor soil scienceen
dc.subject.classification1965 Dissertation S125
dc.titleMechanism of iron chlorosis in grain sorghumen
dc.typeThesisen and Soil Scienceen A&M Universityen of Philosophyen D. in Plant and Soil Scienceen
dc.contributor.committeeMemberHacskaylo, Joseph
dc.contributor.committeeMemberKunze, George W.
dc.contributor.committeeMemberSmith, James D.
dc.contributor.committeeMemberStorey, J. B.
dc.format.digitalOriginreformatted digitalen
dc.publisher.digitalTexas A&M University. Libraries

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