Photosynthetic performance of contrasting Jatropha curcas genotypes during the flowering and fruiting stages

Gisele Pereira Domiciano,Adilson Kenji Kobayashi,Bruno Galveas Laviola,Alexandre Alonso Alves,Hugo Bruno Correa Molinari

doi:10.1590/s0100-204x2018000100002

Gisele Pereira Domiciano, Adilson Kenji Kobayashi + Show 3 more

Open Access

https://doi.org/10.1590/s0100-204x2018000100002

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Abstract

Abstract: The objective of this work was to evaluate physiological processes in contrasting physic nut (Jatropha curcas) genotypes during the flowering and fruiting stages. Gas exchange parameters were measured using an infrared gas analyzer, and morphological traits were evaluated during each stage under natural conditions, in a randomized complete block design with five replicates. Differences in yield between J. curcas accessions were not related to photosynthetic performance, but rather to the number of inflorescences and female flowers, which are genetically determined. Moreover, the net CO2 assimilation was equivalent in both genotypes, although they produced different amount of fruit. The genotypes differed consistently in terms of carboxylation efficiency and ribulose bisphosphate regeneration. Finally, J. curcas branch growth is not impaired by the increased sink strength during fruiting, and fruit may have been actually exerting a positive effect on the net CO2 assimilation, which may have enabled plants to maintain growth while producing flowers and fruits.

Highlights

J. curcas branch growth is not impaired by the increased sink strength during fruiting, and fruit may have been exerting a positive effect on the net CO2 assimilation, which may have enabled plants to maintain growth while producing flowers and fruits
Physiological adaptations of Jatropha curcas have been recently studied in two regions of Brazil, with different climates: a semi-arid tropical climate, known as the Agreste; and a semi-humid tropical climate subjected to water stress (Santos et al, 2013)
The experiments were carried out using the J. curcas active germplasm collection maintained at the experimental station of Empresa Brasileira de Pesquisa Agropecuária (Embrapa) Cerrados, located at Planaltina, DF, Brazil (15°35'30"S, 47°42'30"W, at an altitude of 1,007 m)

Summary

Introduction

Physiological adaptations of Jatropha curcas have been recently studied in two regions of Brazil, with different climates: a semi-arid tropical climate, known as the Agreste; and a semi-humid tropical climate subjected to water stress (Santos et al, 2013). The study showed that the higher vapor pressure deficit of air during the dry season may induce stomatal closure, contributing to a reduction in the net photosynthetic rate. The authors found that J. curcas displays dynamic photoinhibition, even in the dry season, and that plants only showed chronic photoinhibition under conditions of severe water deficit. Jatropha curcas has not yet been studied in the Brazilian cerrado (savannah-like vegetation), which represents the major agricultural area in Brazil and is a strong candidate for the future cultivation of this species (Durães et al, 2011). The largest germplasm collection of J. curcas in the country is

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