Leaf analysis finds high levels of chloride and low levels of zinc and manganese in Louisiana citrus¹

Abstract

A survey of the nutrient status of the citrus groves of Louisiana was conducted to determine the extent of possible deficient or toxic areas of the region and to help determine the accuracy of critical values developed in the major citrusgrowing regions of the world and their relevance to a region where critical values had not been developed. The nutrient status of 29 orchards of Washington navel orange (Citrus sinensis) and satsuma mandarin (Citrus unshiu) trees on P. trifoliate rootstock representing 90% of the citrus region in Louisiana were determined using critical values from the literature. Twenty percent of survey samples ranked excessively high in chloride indicating possible toxicity from recent salt-water intrusion. Chloride contents were higher in groves closer to the Gulf of Mexico. More than 60% of the leaf 1 Approved for publication by the Director of the Louisiana Agricultural Experiment Station as manuscript no. 95-09-9243. 733 734 BELL, VAUGHN, AND BOURGEOIS samples analyzed were diagnosed as having very low concentrations of zinc (Zn) and manganese (Mn). Soil tests of surface soils to a 15-cm depth did not prove useful in predicting Zn and Mn nutrition of trees, as all soil samples had medium or high levels of DTPA-extractable Zn and Mn. Phosphorus (P) and potassium (K) were low in more than 20% of the leaf samples and high in less than 5% of the samples. Calcium (Ca) in the young leaves was low or very low in 95% of the samples, but no samples from older leaves were low or very low in Ca. These results indicate possible transient effects, errors in the critical values used, or environmental conditions that inhibit Ca uptake.

Zinc deficiency in field‐grown pecan trees: changes in leaf nutrient concentrations and structure

“…Leaflet area and TCSA were significantly reduced in both levels of Zn deficiency (Table 2): leaflet area decreased by 24 and 64% in trees with chlorotic and necrotic leaves, respectively, whereas TCSA decreased by 27 and 57% in the same trees when compared to the Zn‐sufficient controls. Similar effects of Zn deficiency on growth parameters have been reported for pecan,16, 24, 34 and other fruit tree species such as peach ( Prunus persica ),35 apple ( Malus domestica )36 and mandarin ( Citrus reticulata ) 37, 38. Reductions in growth parameters with Zn deficiency have also been reported in annual species such as Phaseolus vulgaris 39 and Triticum aestivum 40…”

Cytological and Ultrastructural Evaluations of Zinc Deficiency in Leaves

“…Size decrease, including small leaves and rosetting, due to zinc deficiency has been reported in peach (Prunus Persica (L.) Batsch.) (Arce et al, 1992), citrus (Citrus sinensis L. and C. unshiu L.) (Bell et al, 1997), apple (Malus ×domestica Borkh.) (Ganai et al, 1982), tomato (Lycopersicon esculentum L.) (Parker, 1992), navy bean (Phaseolus vulgaris L.) (Jolley and Brown, 1991), and wheat (Triticum aestivum L.) (Cakmak et al, 1996).…”

Chloride as a Beneficial Macronutrient in Higher Plants: New Roles and Regulation

“…This apparent discrepancy may be due to the type of treatment applied. While prolonged treatments below 5–10 mM Cl − can determine high leaf accumulations with no stress symptoms and/or positive growth responses, shorter salt stress treatments above 10–15 mM Cl − can produce symptoms of toxicity with relatively low leaf Cl − contents [5,25,26,27,28,29]. This is indicative that moderate Cl − applications enable adequate transport and distribution of Cl − at the subcellular, organ, and whole-plant levels (e.g., optimal rates of root uptake, xylem translocation, shoot accumulation, and intracellular compartmentalization).…”