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

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 CO 2 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 CO 2 assimilation, which may have enabled plants to maintain growth while producing flowers and fruits. Desempenho fotossintético de genótipos contrastantes de pinhão-manso durante estádios de florescimento e frutificaçãoResumo -O objetivo deste trabalho foi avaliar processos fisiológicos em genótipos contrastantes de pinhão-manso (Jatropha curcas), durante as fases de florescimento e frutificação. As trocas gasosas foram mensuradas com analisador de gás por infravermelho, e as características morfológicas foram avaliadas em cada fase sob condições naturais, em delineamento de blocos ao acaso, com cinco repetições. As diferenças no rendimento entre os acessos de J. curcas não estiveram relacionadas ao desempenho fotossintético, mas sim ao número de inflorescências e flores femininas, que são geneticamente determinadas. Além disso, a assimilação líquida de CO 2 foi similar em ambos os genótipos, apesar de eles terem diferido na produção de frutos. Os genótipos diferiram consistentemente quanto à eficiência de carboxilação e à regeneração da ribulose bifosfato. Finalmente, o crescimento de ramo de J. curcas não é prejudicado pelo aumento no dreno durante a frutificação, e os frutos possivelmente estavam exercendo efeito positivo na assimilação líquida de CO 2 , o que pode ter permitido que as plantas mantivessem o crescimento ao produzir flores e frutos.Termos para indexação: Jatropha curcas, biodiesel, eficiência de carboxilação, trocas gasosas, capacidade fotossintética.This is an open-access article distributed under the Creative Commons Attribution 4.0 International License Photosynthetic performance of contrasting Jatropha curcas genotypes 11 Pesq. agropec. bras., Brasília, v.53, n.1

Diurnal and seasonal gas exchange characteristics of Jatropha curcas leaves

“…2b). The stomatal closure get induced by adverse environmental factors (Kosugi et al 2009;Domiciano et al 2018) and circadian rhythms to protect the photosynthetic apparatus from photoinhibition and photooxidation due to operation of enhanced photorespiration process, which releases internal CO 2 as a measure to safe-guard the photosynthetic green tissue (Singh et al 1996;Fukuzawa et al 2012;Santos et al 2013;Abrar et al 2020). The gradual increase in PPFDs up to 2000 µmol/m 2 s enhanced gs and A.…”

“…It is a multipurpose, drought resistant, and perennial eudicotyledon plant belonging to Euphorbiaceae family (Pompelli and Orozco 2011;Verma et al 2014Verma et al , 2021. The species has great economic potential, and is used in the pharmaceutical and cosmetic industries, as greater economic interest lies in the seeds, which are used in the production of oils for biodiesel (Kheira and Atta 2009;Domiciano et al 2018;Verma et al 2021). In recent past, Jatropha planting programmes scaled-up millions of marginal farmers and landless people across India through attractive schemes (Kant and Wu 2011;Verma et al 2021).…”

“…Jatropha curcas gained prominence as a native species due to being strongly tolerant to water deficit conditions (Pompelli et al 2010;Abrar et al 2020) with the beginning of its economic importance worldwide. It exhibits a higher water loss and insufficient water availability (Meng et al 2009;Santos et al 2013) and can be grown against various environmental variables with precipitation between 200 and1500 mm yearly (Domiciano et al 2018).…”

“…Drought conditions impair A and E, as also observed in an environment having evaporative demand very high (Abrar et al 2020). Consequently, photochemical damage to photosystem II (PSII) may be induced under such conditions (Saibo et al 2009;Domiciano et al 2018) associated with an increase in the production of reactive oxygen species (ROS) in the chloroplast. Antioxidant enzymes viz., superoxide dismutase (SOD), and catalase (CAT) confer oxidative defense system for the protection of the cells against adverse effects of ROS (Gao et al 2008;Verma et al 2021).…”

“…Oftenly, the leaf-to-air VPD and the temperature often reach their maximum values during plantation in Indian climate (April-May). Reduced gs may lead to decrease in CO 2 availability, resulting loss in photosynthesis activity (Ribeiro et al 2009;Domiciano et al 2018). Photosynthesis is a key physiological process related to plant performance, influenced by light, temperature, VPD and sufficient water supply (Fukuzawa et al 2012;Fini et al 2013;Vongcharoen et al 2019).…”