Ca²⁺ and Mg²⁺‐Stimulated ATPases from Roots of Plantago lanceolata, Plantago media and Plantago coronopus: Response to Alterations of the Level of Mineral Nutrition and Ecological Significance

Abstract

Growth of Plantago lanceolata L., P. media L. and P. coronopus L. was followed at two levels of mineral nutrition (low-salt and high-salt). In addition the response of transfer of plants from lowsalt conditions to high-salt conditions and vice versa was studied. Growth of these Plantago species was not much affected by the nutritional level. P. coronopus showed the least dependence on the level of mineral nutrition.The Ca^+-and Mg^^-stimulated ATPase activity of microsomal preparations of the roots of Plantago was also studied. A pH optimum at pH 6.5 was observed in all species, together with a relatively high ATPase activation by Mg^+ in P. lanceolata, by Ca^+ in P. media, and by both ions in P, coronopus. The specific activity of the ATPases was highest in preparations from low-salt roots.The three species all occur in relatively nutrient-poor habitats, but they are at the same time particularly adapted to circumneutral soils (P. lanceolata), to Ca^+-rich soils {P. media) and to alternating levels of mineral nutrition {P. coronopus). The properties of the ATPases {K^, V^^^, protein content) and the growth are discussed in relation to these ecological properties of the species.

The Effect of Salinity on Growth, Cation Content, Na+‐Uptake and Translocation in Salt‐Sensitive and Salt‐Tolerant Plantago Species

“…At lower salinity growth of shoots was less affected than that of roots, while at high salinity growth ofthe shoots was more retarded as shown by the changes in the shoot/root ratio. The lowered ratio at high NaCl concentrations may have an adaptive value (Kuiper and Kuiper 1979a), since under saline conditions the absorption of essential nutrients may be hindered. The increase in dry weight percentage of plants with increasing NaCl concentration can be attributed to high internal ion content rather than to the increased production of organic compounds.…”

Genetic differentiation in Plantago major: Ca2+‐ and Mg2+‐stimulated ATPases from roots and their role in phenotypic adaptation

“…If the changes in the studied ATPase and its V^^â nd/or K^ values upon a change of plants to a different nutritional status are regarded as a mechanism for physiological plasticity in genotypes, then the conclusion is that the species P. major possesses a rather poor flexibility. The rather poor flexibility of P. major is particularly evident in comparison with the flexibility of Plantago lanceoiata L., demonstrated by Barber et al (1968), Warwick and Briggs {1979) and Kuiper and Kuiper (1979b).…”

Substrate‐dependent modulation of ATPase activity by Na+ and K+ in roots of Plantago species

“…for substrate, and for Na"^ and K"^; (c) an ATPase complex, built up from separable units such as the catalytic unit, Na"*"-and Table 1, Kinetic data as obtained by analysis of the experimental curves in Figure 5. The existence of separate Mg-and Ca-ATPases in Plantago is unlikely since the main kinetic characteristics of the ATPase in the presence of Mg^"^ or Ca^"^ are very similar (Kuiper and Kuiper 1979a,b), On the basis ofthe regulative interaction between Na"^ and K"^ and Mg-ATPase, a separate K"^-ATPase and Na"^-ATPase can also be excluded, A similar ATPase preparation from P. maritima has been characterized by two pH optima, one of them being in the alkaline region (Kuiper and Kuiper 1979a). However, all of the ATPase assays reported now, were carried out at pH 6,5, thus the contribution of the alkaline ATPase to the measured activities was probably negligible.…”