UNRAVELING PHYSIOLOGICAL TRAITS OF Jatropha curcas, A BIODIESEL PLANT, TO OVERCOME SALINITY CONDITIONS

Yuri Lima Melo,Eduardo Alfonso Ortega Delgado,Cristiane Elizabeth Costa De Macêdo,Josemir Moura Maia,Patricia Ortega-Rodés,Rosa Rodés Garcia

doi:10.1590/1983-21252020v33n217rc

Abstract

ABSTRACT Dry land systems spread all over the world and comprise 41.3% of the terrestrial area, which host 34.7% of the global population, so it is convenient to propose crops able to grow there. Jatropha curcas is a plant adapted to arid and semiarid regions as well as sub-humid conditions, being a potential source of biodiesel. The challenge is to understand the physiology of J. curcas, which enables it to live under saline and drought conditions. The seeds of J. curcas used came from Ciego de Ávila Province, Cuba. Seven-day-old seedlings were cultivated in 1.5 L pots with half strength Hoagland solution for 42 days under semi-controlled conditions. NaCl added to solutions in pots provided 75 or 150 mM treatments for 240 h before measurements. Leaf growth, net photosynthesis and stomatal pore area were affected by 150 mM NaCl. Non-photochemical quenching of leaves was only changed by 150 mM NaCl after 24 h; the electron transport rate had a tendency to decrease in leaves under saline conditions. The gene expression pattern changed for SOS1 and HKT1 according to the NaCl used in the medium, indicating active mechanism to deal with Na+ in the cell. In general, Cuban J. curcas plants were able to grow and perform photosynthesis under 75 mM NaCl, which represents 7 dS m-1, a condition that restricts growth for many plant species.

Highlights

It is estimated that approximately 20% of the cultivated land in the world and almost half of all irrigated land is affected by salinity (SHIRIVASTAVA; KUMAR, 2015)
Our results show that after 24 h of salt stress, J. curcas L. leaves decreased the electron transport rate (ETR)
In our work we found that mainly SOS1 and HKT1 modified the expression pattern depending the NaCl concentration

Summary

Introduction

It is estimated that approximately 20% of the cultivated land in the world and almost half of all irrigated land is affected by salinity (SHIRIVASTAVA; KUMAR, 2015). Soil salinity is a serious environmental problem especially in arid and semiarid areas (ALLBED; KUMAR, 2013), where evapotranspiration rate generally exceeds rainfall. Salt stress interferes with plant growth, changing metabolic, physiological and anatomical features, which contributes to the reduction of crop yield and causes enormous economic losses. The accumulation of intracellular Na+ during salt stress conditions could change the K+/Na+ ratio, which seems to affect the photosynthetic process (BRUGNOLI; BJÖRKMAN, 1992). Under environmental conditions that are unfavorable for the photosynthetic fixation of CO2, an excess of light energy absorbed by photosynthetic pigments accelerates photoinhibition; plants exhibit different strategies to protect themselves against photoinhibition and photosynthetic damage (TAKAHASHI; BADGER, 2011)

Methods

Results

Conclusion