Desempenho fotossintético de plantas de Jatropha curcas L. cultivadas no Estado Espírito Santo

Abstract

In this work we used plants of Jatropha (Jatropha curcas L.) in the same stage of development and under the same conditions of cultural management, grown in two commercial farms: one in the north coast (Depth of Ipiranga, Linhares) and the other in northwest, mountainous (Itarana) State of the Holy Spirit in order to evaluate the photosynthetic performance in situ. Measurements were carried out over a year (May/2010 to May/2011) growth, chlorophyll content, gas exchange, fluorescence transient and modulated chlorophyll a. In vitro analysis of chlorophyll content and activity of antioxidant enzymes were also performed. The results showed that plants grown in the state of the Holy Spirit had higher growth in real time and greater efficiency of water use (A/E). The plants of this region also showed lower antioxidant activity (SOD, CAT and APX) in response to the expected lower production of reactive oxygen species (ROS). Plants grown on the coast, with lower availability of soil nutrients, showed higher levels of chlorophyll a and b, higher rates of net photosynthesis (A) and higher rates of photochemical performance. It is inferred therefore that the Jatropha plants have adaptive strategies that allow them to live in adverse environmental conditions. In addition, the chlorophyll a fluorescence transient was efficient to evaluate the photosynthetic performance of plants of Jatropha grown under environmental stress conditions: water, heat and nutrition