Environmental and Economic Values of salt tolerance. Euphorbia tirucalli: Phytoremediation potential

Abstract

Halophytes, such as Euphorbia tirucalli, are used for medicinal and economic purposes, as well as for the recovery of degraded environments through bioremediation or phytoremediation. In parallel, Vigna unguiculata, which also has high tolerance to saline environments, has high nutritional value generating economic interest. Furthermore, biofuel production can be reduced in cost and complexity if we use plant raw material that can grow in salinized and poor soils. The reduction of arable land, due to increased soil salinization and the depletion of freshwater resources, poses a threat to agricultural production. In this work we aimed to evaluate the saline stress in V. unguiculata seeds generated from the chemical elicitation of E. tirucalli and the solution of Spongia tosta 10DH. In the first experiment, we cultivated V. unguiculata in water with 10% solutions obtained from aerial parts of E.tirucalli from the coast of Rio de Janeiro. In the second experiment, we cultivated V. unguiculata, which were treated with E. tirucalli hormetic solution - 5H from Seropedica/RJ and Spongia tosta 10DH solution. In all experiments there was inhibition of germination associated to seed engorgement. In our tests, therefore, the evaluated extracts suggested that also will be able to act as phytoremediation agents, via desalination through the Na++/K+ pump mechanism. From our essays, observations and reasoned discussion, we postulate the hypothesis that E. tirucalli can act in filtering gardens of environmental pollutants by this way. Novel ecophysiological investigations will be carried out.