Soil Science Society of America Journal · 1972 · 63 citations · 24 references
AgricultureAgronomyCrop SciencesCrop PhysiologyNutrient CyclingPlant NutritionNitrogen AssimilationNutrient AssimilationNutrient AvailabilityNutrient UptakeNutrient Uptake By PlantsRoot NutritionAssimilate TranslocationIsotope DilutionIsotope Dilution AnalysisNitrate AssimilationNitrate TransportNitrate UptakePlant Nitrogen UptakeRoot Nitrogen Uptake
Abstract The uptake patterns of NH 4 + and NO 3 ‐ in lettuce plants ( Lactuca sativa L., cultivar ‘Climax’) were determined using inverse 15 N isotope dilution techniques under air and root temperatures of 8, 13, 18, and 23C and the same air temperatures with an initial root environmental temperature of 2C. The absorption patterns for both NH 4 + and NO 3 ‐ at each nutrient solution and air temperature were linear functions of time. The absorption rates for NH 4 + and NO 3 ‐ were increased by increasing the air, root, or both air and root environmental temperatures. Nitrate uptake was influenced more by temperature than the absorption of NH 4 + . The NH 4 + to NO 3 ‐ absorption ratio increased when the temperature decreased. A higher temperature coefficient for NO 3 ‐ was obtained. The translocation rates to tops for NH 4 + increased as temperature increased from 8 to 23C, but reached a maximum at 18C for NO 3 ‐ .
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