Browsing by Author "Vijayalakshmi, S"

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    Effect of rare earth elements on growth and nutrition of coconut palm and root competition for these elements between the palm and Calotropis gigantea
    (JOURNAL OF PLANT NUTRITION, 2000) Wahid, PA; Valiathan, MS; Kamalam, NV; Eapen, JT; Vijayalakshmi, S; Prabhu, RK; Mahalingam, TR
    Absorption of rare earth elements (REEs) namely lanthanum (La), cerium (Ce), praseodymium (Pr), and neodymium (Nd) by coconut, competition between coconut and Calotropis gigantea L. for these elements in mixed culture and the effects of the REEs on growth and nutrition of the palm were studied in a pot culture. Ata low rate of application, REEs promoted root growth in coconut, but at a higher level, absorption of phosphorus (P) and zinc (Zn) by the palm was reduced significantly. Absorption of REEs by the palm tended to increase with increasing application rates, but the increases were not statistically significant. Although Calostropis gigantea accumulated more REEs per unit dry matter than coconut, it failed to compete effectively for REEs in mixed culture with coconut. However, in mixed culture, coconut depressed the absorption of REEs by Calostropis gigantea.
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    Foliar levels of rare earth elements and thorium in coconut palm in relation to root (wilt)-disease
    (CURRENT SCIENCE, 1998) Wahid, PA; Kamalam, NV; Vijayalakshmi, S; Prabhu, RK; Mahalingam, TR; Eapen, JT; Dang, HS; Jaiswal, DD; Balachandran, PV; Venugopal, VK; Suresh, PR; Unnithan, VKG; Thomas, J
    Concentrations of major nutrients and micronutrients, rare earth elements (REEs), Th and nutrient/REE ratios in the leaves of diseased and apparently healthy coconut palms of the root (wilt)-disease affected tract and healthy palms of the disease-free tract, covering three major soil types of Kerala, namely alluvial (entisols), laterite (ultisols), and sandy (entisols), were examined in relation to the disease, Accumulation of major nutrients, especially K, was generally observed in the leaves of diseased palms. Mg content of leaves of palms growing on laterite soil in disease-affected tract was lower than that of palms in the disease-free tract The leaf concentrations of La, Ce, Pr, Nd, Sm, Gd and Th did not show significant differences between healthy and diseased palms, The only exception to this trend was Gd whose concentration was less in the diseased and apparently healthy palms growing on laterite soil of the disease-endemic area than that in the healthy palms of the disease-free area, Some of the essential plant nutrients (EPN)/La, and EPN/Ce ratios were significantly different in palms of the disease-affected tract compared to that in palms of the disease-free tract indicating imbalances in the relative concentrations of EPNs and REEs, These results call for more detailed study of the geochemical differences between the disease-affected and disease-free tracts for identification of the soil chemical factors associated with the incidence of the disease.