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Abstract
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The effect of various Mg concentrations (0, 1, 2, 3 and 4 mM) in the nutrient solution on
plant growth, fruit quality and sugars content in hydroponicallygrown cucumber (Cucumis
sativuscv. Nagen 792) under optimum(100%)and low (50%) light intensities was
evaluated.The results showed that the decreases in the dry matter, SPAD index and soluble
protein and accumulation of soluble sugar and starch content in the leaves Mg deficiency
(0 mM Mg)are suggestive of decreased growth, and the decrease induced by Mg
deficiency was bigger under low light intensity than under optimum light intensity. Plant
growth was improved at 3 mM Mg, but it was reduced when the Mg concentration
increased (4 mM Mg). Concentration of Mg in the leaf and fruit increased drastically with
increasing Mg in the nutrient solution. This became steadily more pronounced under low
light intensity. Mg deficiency plants (0 mM Mg) developed visible symptoms- interveinal
necrosis in middle leaves, especially optimum light intensity.Fruit quality traits such as
fruit dry matter percentage and total soluble solid (TSS) and fruit Fv/Fm were increased at
higher concentration of Mg (3 mM) in the solution, especially under optimum light
intensity. But, fruit firmness was improved at lower concentration of Mg (1 mM) in the
solution especially in optimum light intensity In conclusion, Mg requirement of cucumber
plants likely increases with light intensity. Thus, higher concentration of Mg (3 mM) in thenutrient solution was the most favorable for cucumber plant growth and fruit quality grown
in hydroponics.
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