1298:
Influence of Elevated Phosphorus Levels In Nutrient Solution On Micronutrient Uptake and Deficiency Symptom Development In Strawberry Cultured with Fertigation System

Sunday, July 26, 2009
Illinois/Missouri/Meramec (Millennium Hotel St. Louis)
Jong Myung Choi , Pai Chai University, Daejeon 302-735, South Korea
Chiwon W. Lee , North Dakota State Univ, Fargo, ND
The relationship between the total amount of micronutrients absorbed by the above-ground plant part and the occurrence of visible micronutrient deficiency symptoms in strawberry (Fragaria×ananassa Duch.) as influenced by elevated phosphorus (P) levels in fertigation solution was investigated. Stolon-propagated plants of two strawberry cultivars, ‘Seonhong’ and ‘Keumhyang’, were cultured in the field and irrigated with a standard fertilizer solution containing 0, 0.5, 1, 2, 4, or 6 mM P. Dry matter yield and tissue nutrient content were determined on plants harvested 120 days after transplanting. Plant growth response to increased P levels in fertilizer solution was cubic, with the highest dry matter production occurring at 0.5, 1.0 and 2.0 mM P in Keumhyang and at 0.5 and 1.0 mM P in Seonhong. The pattern of P accumulation in the tissues of the two cultivars as influenced by elevated nutrient solution P levels showed a quadratic response, while the total amount of P contained by the above-ground plant part decreased when P concentration in nutrient solution was higher than 4 mM in Keumhyang and 2 mM in Seonhong. Young leaves of the plants grown with nutrient solution P levels higher than 4 mM and 2 mM, respectively, in Keumhyang and Seonhong, developed interveinal chlorosis with pale green color. Tissue concentrations of iron (Fe), copper (Cu), manganese (Mn) and zinc (Zn) in both cultivars, when expressed as mg·kg-1 dry weight, did not decrease even in the treatments in which deficiency symptoms were observed. The total amount of these metallic micronutrients absorbed by the above-ground plant part decreased in the treatments in which nutrient deficiencies were observed. The total amount of absorbed micronutrients showed a cubic response to increasing P levels in nutrient solution. Result of this study indicates that total amount of micronutrients taken up by the plant, not tissue concentration, is a better indicator of P-induced micronutrient deficiency in the two cultivars of strawberry tested.