Poster: Late and Moved Abstracts

Abs # 1011: Dynamics of nutrient uptake during root and shoot growth in three diverse citrus rootstock cultivars

Presenter:	Albano, Joseph P, jalbano@ushrl.ars.usda.gov
Authors	Albano, Joseph P (A)   Kuehny, Jeff S (B)   Bausher, Michael G (A)   Evens, Terrence J (A)   Bowman, Kim D (A)
Affiliations:	(A): USDA, ARS, U.S. Horticultural Research Laboratory (B): Louisiana State University, Department of Horticulture

The objective of the study was to define nutrient uptake patterns in three genetically diverse citrus rootstock cultivars: Swingle citrumelo (Citrus paradisi Macf. X Poncirus trifoliata [L.] Raf.), Volkamer lemon (C. volkameriana Ten. and Pasq.), and Cleopatra mandarin (C. reticulata Blanco), under different environmental and nutritional conditions during episodes of root and shoot growth. Plants were grown hydroponically in an aerated, complete nutrient solution in a greenhouse. Nutrient solution was changed weekly and analyzed to determine nutrient depletion. Weekly, shoot and root growth was measured non-destructively by subtracting plant fresh weight with roots submerged in water from total plant fresh weight. Increased uptake of Ca, K, P and Mg and micronutrients Fe, Mn, Cu, and Zn preceded initiation of shoot growth of all rootstock cultivars by 7 to 14 days. As comparison of weighted means, the qualitative pattern of uptake over the course of a shoot growth episode was similar for Ca and K, P and Mg, and Zn and Fe. Copper uptake was the most erratic, showing no distinct pattern during shoot growth. During shoot growth the greatest quantitative uptake of macronutrients, was for Ca and K, and of the micronutrients, Mn.