DIFFERENTIAL RESPONSE OF THE EDAPHIC ECOTYPES IN CYNODON DACTYLON (L) PERS. TO SOIL CALCIUM

Abstract

SUMMARYThis paper describes the differential response to calcium of the three edaphic ecotypes of Cynodon dactylon (L) Pers. growing, respectively, on non-calcareous, moderately calcareous, and highly calcareous soils. A close correlation was discernible for the three populations with the habitats they occupy in nature. The population from a highly calcareous soil showed a better yield in calcareous soils than in non-calcareous soils, though in highly calcareous soils it tended to decrease. The reverse was found to be the case for the population from non-calcareous soils; the population from moderately calcareous soil showed an intermediate behaviour. Significantly different responses were found between the three populations with regard to mineral uptake in both calcareous and non-calcareous soils. Although calcium uptake was higher in the case of plants from non-calcareous soils compared to those from calcareous soils in experiments using calcareous and non-calcareous soils, in extremely calcareous soil the reverse was found to be the case. The ash content and the uptake of calcium, potassium and magnesium, in general, increased with increase in soil calcium level. However, the calcium uptake of the populations from moderately calcareous or non-calcareous soils and the magnesium uptake of the latter decreased in highly calcareous soils. It is concluded from the present studies that there are at least three 'edaphic ecotypes' within this species, each markedly different from the other in its physiologic-ecological attributes and that the basis for the differentiation is chiefly due to their response to soil calcium.

AN EXPERIMENTAL STUDY ON TWO POPULATIONS OF CHAMAENERION ANGUSTIFOLIUM (L.) SCOP. (=EPILOBIUM ANGUSTIFOLIUM L.) OCCURRING ON CONTRASTING SOILS, WITH PARTICULAR REFERENCE TO THE RESPONSE TO BICARBONATE

“…1961, 1969) emphasized the significance of comparisons between populations within a single species in studying physiological adaptations to contrasting soil types, and has been confirmed by other studies (e.g. Ramakrishnan and Singh, 1966;Hutchinson, 1968). The present study deals with two populations of Chamaenerion angustifolium, one growing on an alkaline soil, the other on an acid soil.…”

“…With regard to Ca the content in the tissues was equal in both natural populations despite the considerably higher availability at the alkaline site. This could be caused by a greater efficiency of uptake of the population on the acid site as has been established for Eestuca ovina (Snaydon and Bradshaw, 1961), Cynodon dactylon (Ramakrishnan and Singh, 1966), Trifolium repens (Snaydon and Bradshaw, 1969), Melilotus alba (Ramakrishnan, 1968), and Hypericum perforatum (Ramakrishnan, 1969). Another explanation, which does not contradict differences in efficiency of uptake, was suggested by Rhoads and Wallace (1960) namely that the frequently observed decrease in the content of Ca in the leaves of plants suffering lime chlorosis could be due to precipitation of Ca-oxalate in the roots (the oxalate is produced in excess due to dark fixation of COj).…”

NUTRITIONAL REQUIREMENTS OF THE EDAPHIC ECOTYPES IN MELILOTUS ALBA MEDIC.

“…The 'acidic' type was found to have a better ability to accumulate calcium from a low calcium medium thus suggesting that the occurrence of the 'acidic' type in a non-calcareous site is due to a more efficient accumulation of this nutrient rather than to its ability to metabolize at a low internal concentration. A similar situation has been encountered in other species as in the case of the noncalcareous population of Euphorbia thymifoUa (Ramakrishnan, 1961), and of C'vnodon dactvlon (Ramakrishnan and Singh, 1966).…”

“…Such a wide range of tolerance may be due either to the plasticity of the same population of the species or, often, to the presence of physiologically distinct, genetically determined ecological races within the species as was demonstrated in Euphorbia thymifoUa (Ramakrishnan, 1961(Ramakrishnan, , 1965a and Cynodon dactylon (Ramakrishnan and Singh, 1966). Such inherent differences between edaphic eeotypes may be due to different capacities for mineral uptake or distinct, internal, nutritional needs.…”

Differential responses to Na+/K+ and Ca2+/Mg2+ in two edaphic races of the Lasthenia californica (Asteraceae) complex: A case for parallel evolution of physiological traits

“…Previous studies on plant‐soil relations provide examples of intraspecific differences in accumulation of and/or tolerance to Na + (Ashraf et al ., 1989), K + (Flowers & Lauchli, 1983; Siddiqi & Glass, 1983), Ca 2+ (Snaydon & Bradshaw, 1961, 1969; Ramakrishnan & Singh, 1966), Mg 2+ (Main, 1974), and heavy metals (Antonovics et al ., 1971). In the case of heavy metals, evolution of intraspecific tolerance can be rapid, taking place within only a few generations (Wu et al ., 1975).…”