{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/71789"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/71789","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Physiological Studies on Nitrate Absorption and Accumulation in Lettuce (Lactuca Sativa L.) Genotypes","abstract":"Made available in DSpace on 2014-12-16T20:45:20Z (GMT). No. of bitstreams: 1 8908684.pdf: 4598257 bytes, checksum: 01a6e2bf3309b072975d1d75575f467c (MD5) Previous issue date: 1988","abstract_html":"Made available in DSpace on 2014-12-16T20:45:20Z (GMT). No. of bitstreams: 1 8908684.pdf: 4598257 bytes, checksum: 01a6e2bf3309b072975d1d75575f467c (MD5) Previous issue date: 1988","abstract_has_math":false,"creators":["Freiji, Fadi George"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Horticulture","degree_department":null,"school":null,"contributors":["Swiader, John M."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-12-16T20:45:20Z","date_published":"2014-12-16T20:45:20Z","updated_at":"2026-07-22T22:26:05Z","subjects":["Biology, Plant Physiology"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8908684"],"render_values":[{"text":"(UMI)AAI8908684","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/71789","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Swiader, John M."]},{"key":"dc:creator","label":"Author","values":["Freiji, Fadi George"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-16T20:45:20Z","10000-01-01","1988"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Horticulture"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Biology, Plant Physiology"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/71789","(UMI)AAI8908684"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Made available in DSpace on 2014-12-16T20:45:20Z (GMT). No. of bitstreams: 1 8908684.pdf: 4598257 bytes, checksum: 01a6e2bf3309b072975d1d75575f467c (MD5) Previous issue date: 1988","Embargo set by: Seth Robbins for item 71955 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Nitrate uptake by lettuce from nutrient solution over concentrations below 100 $\\mu$M NO$\\sb3\\sp-$ showed a single-phase saturation pattern typical of Michaelis-Menten kinetics. The NO$\\sb3\\sp-$ uptake system was saturated at NO$\\sb3\\sp-$ concentrations between 40 and 90 $\\mu$M, and exhibited relatively high net uptake capacity and high affinity for NO$\\sb3\\sp-$.","Initially, depletion of NO$\\sb3\\sp-$ was considerably slower in plants pretreated with minus-N solution ($-$N) for 45 hours before depletion than in plants continuously supplied with NO$\\sb3\\sp-$ (+N). Root NO$\\sb3\\sp-$ concentrations were significantly decreased by the $-$N pretreatment. Net NO$\\sb3\\sp-$ influx decreased while the root affinity for NO$\\sb3\\sp-$ increased with increasing plant age and lower root NO$\\sb3\\sp-$ concentrations. The data suggest that NO$\\sb3\\sp-$ uptake in lettuce is an efficient process inducible by internal NO$\\sb3\\sp-$. The results also support the hypothesis of allosteric regulation of NO$\\sb3\\sp-$ uptake by internal NO$\\sb3\\sp-$ concentration, and the contention that the NO$\\sb3\\sp-$ uptake carriers may exhibit gradual degradation during prolonged NO$\\sb3\\sp-$ deprivation.","Genetic variation in leaf NO$\\sb3\\sp-$ accumulation was evident among the four lettuce genotypes used. Leaf NO$\\sb3\\sp-$ accumulation in butterhead genotypes (but not in cos lettuce) decreased as organic N concentrations in the roots increased. Genotypic differences in leaf NO$\\sb3\\sp-$ accumulation, however, could not be explained on the basis of differences in root organic N concentration. Apparently, accumulation differences of NO$\\sb3\\sp-$ among genotypes were not solely the result of variation in their root reduction capacity. Nitrate levels in the leaves were not affected by the NO$\\sb3\\sp-$ partitioning pattern between the roots and leaves of the lettuce genotypes. A differential capacity for NO$\\sb3\\sp-$ uptake of whole plants was noted among cultivars which was consistent with their differential capacity to accumulate NO$\\sb3\\sp-$ in the leaves. All genotypes, however, had similar root uptake capacities.","It is proposed that root organic N concentration could be a good indicator of the leaf NO$\\sb3\\sp-$ accumulation potential in lettuce. However, breeding efforts should not focus only on increased production of organic N in the roots, but also on developing lettuce cultivars with relatively faster growth rates resulting in growth dilution of the NO$\\sb3\\sp-$ absorbed and translocated from the roots to the leaves.","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","125 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1988."]},{"key":"dc:title","label":"Title","values":["Physiological Studies on Nitrate Absorption and Accumulation in Lettuce (Lactuca Sativa L.) Genotypes"]}]}],"canonical_facts":{"dc:contributor":["Swiader, John M."],"dc:creator":["Freiji, Fadi George"],"dc:date":["2014-12-16T20:45:20Z","10000-01-01","1988"],"dc:description":["Made available in DSpace on 2014-12-16T20:45:20Z (GMT). No. of bitstreams: 1 8908684.pdf: 4598257 bytes, checksum: 01a6e2bf3309b072975d1d75575f467c (MD5) Previous issue date: 1988","Embargo set by: Seth Robbins for item 71955 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Nitrate uptake by lettuce from nutrient solution over concentrations below 100 $\\mu$M NO$\\sb3\\sp-$ showed a single-phase saturation pattern typical of Michaelis-Menten kinetics. The NO$\\sb3\\sp-$ uptake system was saturated at NO$\\sb3\\sp-$ concentrations between 40 and 90 $\\mu$M, and exhibited relatively high net uptake capacity and high affinity for NO$\\sb3\\sp-$.","Initially, depletion of NO$\\sb3\\sp-$ was considerably slower in plants pretreated with minus-N solution ($-$N) for 45 hours before depletion than in plants continuously supplied with NO$\\sb3\\sp-$ (+N). Root NO$\\sb3\\sp-$ concentrations were significantly decreased by the $-$N pretreatment. Net NO$\\sb3\\sp-$ influx decreased while the root affinity for NO$\\sb3\\sp-$ increased with increasing plant age and lower root NO$\\sb3\\sp-$ concentrations. The data suggest that NO$\\sb3\\sp-$ uptake in lettuce is an efficient process inducible by internal NO$\\sb3\\sp-$. The results also support the hypothesis of allosteric regulation of NO$\\sb3\\sp-$ uptake by internal NO$\\sb3\\sp-$ concentration, and the contention that the NO$\\sb3\\sp-$ uptake carriers may exhibit gradual degradation during prolonged NO$\\sb3\\sp-$ deprivation.","Genetic variation in leaf NO$\\sb3\\sp-$ accumulation was evident among the four lettuce genotypes used. Leaf NO$\\sb3\\sp-$ accumulation in butterhead genotypes (but not in cos lettuce) decreased as organic N concentrations in the roots increased. Genotypic differences in leaf NO$\\sb3\\sp-$ accumulation, however, could not be explained on the basis of differences in root organic N concentration. Apparently, accumulation differences of NO$\\sb3\\sp-$ among genotypes were not solely the result of variation in their root reduction capacity. Nitrate levels in the leaves were not affected by the NO$\\sb3\\sp-$ partitioning pattern between the roots and leaves of the lettuce genotypes. A differential capacity for NO$\\sb3\\sp-$ uptake of whole plants was noted among cultivars which was consistent with their differential capacity to accumulate NO$\\sb3\\sp-$ in the leaves. All genotypes, however, had similar root uptake capacities.","It is proposed that root organic N concentration could be a good indicator of the leaf NO$\\sb3\\sp-$ accumulation potential in lettuce. However, breeding efforts should not focus only on increased production of organic N in the roots, but also on developing lettuce cultivars with relatively faster growth rates resulting in growth dilution of the NO$\\sb3\\sp-$ absorbed and translocated from the roots to the leaves.","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","125 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1988."],"dc:identifier":["http://hdl.handle.net/2142/71789","(UMI)AAI8908684"],"dc:subject":["Biology, Plant Physiology"],"dc:title":["Physiological Studies on Nitrate Absorption and Accumulation in Lettuce (Lactuca Sativa L.) Genotypes"],"dc:type":["text"],"thesis:degree_discipline":["Horticulture"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:05Z"}