Effects of calcium deficiency on Coffea arabica. Nutrient changes and correlation of calcium levels with some photosynthetic parameters
Calcium deficiency was induced in hydroponically grown 1.5-years-old coffee plants with 12-14 pairs of leaves. Calcium was given in the form of Ca(NO subíndice 3) subíndice 2: 5, 2.5, 0.1, 0.01 and 0 mM. After 71 days of Ca-treatment root and shoot as well as total biomass were decreased by severe Ca-deficiency. However, a stronger decrease was observed for shoot growth as revealed by the increase in the root/shoot ratio. New leaves were affected showing decreases in the total leaf area and in Leaf Area Duration (LAD). After 91 days of deficiency, leaf protein concentration decreased (by about 45 percent) in the top leaves while nitrate reductase activity (NRA) and NO subíndice 3 content showed no significant changes. Total nitrogen and mineral concentration (P, K, Ca, Mg and Na) were also determined in leaves and roots. With the decrease in calcium concentration in Ca-deficiency conditions, we observed concomitant increases in the concentrations of K+, Mg exponente 2+ and Na + in leaves (maximal changes of 32 percent for K+, 96 percent for Mg exponente 2+ and 438 percent for Na+) and in roots (108 percent for K+, 86 percent for Mg exponente 2+ and 38 percent for Na+). Accordingly, the ratio between elements changed, including the radio N/P, showing a non-equilibrium in the balance of nutrients. Significant correlations were obtained between Ca exponente 2+ concentration and some photosynthetic parameters. Ca-deficiency conditions would increase the loss of energy as expressed by the rise in q subíndice E and decrease the photochemical efficiency, which confirms the importance of this element in the stabilization of chlorophyll and in the maintenance of good photochemical efficiency PS II level.
| Main Authors: | , , , , |
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| Format: | biblioteca |
| Published: |
1995
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| Subjects: | COFFEA ARABICA, CALCIO, DEFICIENCIA DE MINERALES, NECESIDADES DE NUTRIENTES, FOTOSINTESIS, NUTRICION DE LAS PLANTAS, NUTRICION MINERAL, |
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