scholarly journals Differential response of photosystem II and I photochemistry in leaves of two Crambe abyssinica Hochst lineages submitted to water deficit

2020 ◽  
Vol 58 (5) ◽  
pp. 1122-1129
Author(s):  
P.C.S. BRAGA ◽  
J.P.R. MARTINS ◽  
R. BONOMO ◽  
R.M. BORGES ◽  
J.V.G. SILVA ◽  
...  
Author(s):  
Rodrigo Fantin Alves Martins ◽  
◽  
André Felipe Costa Souza ◽  
Carlos Pitol ◽  
Antelmo Ralph Falqueto ◽  
...  

Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 381
Author(s):  
Israel Macias-Bobadilla ◽  
Marcela Vargas-Hernandez ◽  
Ramon G. Guevara-Gonzalez ◽  
Enrique Rico-Garcia ◽  
Rosalia V. Ocampo-Velazquez ◽  
...  

Chili pepper (Capsicum spp.) is one of the most economically important horticultural crops in the world; its production for the food and pharmaceutical industries has been increasing worldwide. The economic importance of this crop is due, in part, to the nutraceutical properties derived from its secondary metabolism. Drought is the main environmental factor that affects crop production. Nevertheless, studies involving water deficit have considered short-term responses to sharp water deficit rather than long-term acclimation processes through moderate and gradually increasing water deficits, which omitted the dynamics and profile of the secondary metabolism that are part of the plant’s defence system against this stress factor. The present study aimed to identify the different mechanisms that chili pepper plants use to cope with drought stress using a progressive decrease and increase of water availability, conditions that commonly occur for crops in open fields. Four treatments were applied as follows: gradual water deficit (GWD), initial waterlogging with gradual water deficit (IWGD), sudden water deficit with gradual recovery (SWDR), and no deficit of water (NDW). These conditions should represent a more real situation similar to that faced by plants in the agricultural environment. In order to evaluate the response mechanisms associated with these water deficits, changes in phenological variables, proline accumulation, and the gene expression of phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), peroxidase (POD), and superoxide dismutase (SOD) were measured in chili pepper plants growing on land under different irrigation regimes in two contrasting soil types in areas where chili pepper plants are cultivated in central Mexico. The variables evaluated showed a differentiated response of the mechanisms in plants growing under different levels of water deficit. Given the differential response observed for the gene expression and morphological and biochemical variables studied in chili pepper plants against different water regimes, in this work, this may have implications for more efficient use of water in crops with high nutraceutical content, in addition to prospects for using products derived from secondary metabolism in the pharmaceutical industry.


2023 ◽  
Vol 83 ◽  
Author(s):  
E. M. M. Bartieres ◽  
D. M. Dresch ◽  
L. C. Reis ◽  
Z. V. Pereira ◽  
R. M. Mussury ◽  
...  

Abstract The objective of this study was to evaluate the activity of antioxidant enzymes, the functioning of the photosystem II and quality of C. xanthocarpa seedlings cultivated under intermittent water deficit and shading levels and the influence of shading on recovery potential after suspension of the stress conditions. The seedlings were subjected to three levels of shading (0, 30, and 70%), six periods of evaluation (start: 0 days; 1st and 2nd photosynthesis zero: 1st and 2nd P0; 1st and 2nd recovery: 1stand 2nd REC; and END), and two forms of irrigation (control: periodically irrigated to maintain 70% substrate water retention capacity, and intermittent irrigation: suspension of irrigation). The plants subjected to intermittent irrigation conditions at 0% shading showed a reduction in water potential (Ψw) and potential quantum efficiency of photosystem II (Fv/Fm) and maximum efficiency of the photochemical process (Fv/F0) and an increase in basal quantum production of the non-photochemical processes (F0/Fm). Superoxide dismutase (SOD) activity was higher in the leaves than in the roots. The C. xanthocarpa is a species sensitive to water deficit but presents strategies to adapt to an environment under temporary water restriction, which are more temporary are most efficient under shading. The seedlings with water deficit at all levels of shading exhibited higher protective antioxidant activity and lower quality at 0% shading. The shading minimizes prevents permanent damage to the photosystem II and after the re-irrigation, the evaluated characteristics showed recovery with respect to the control group, except POD and SOD activities in the leaves.


2016 ◽  
Vol 15 (3) ◽  
pp. 439
Author(s):  
GUILHERME FELISBERTO ◽  
PATRÍCIA APARECIDA DE CARVALHO FELISBERTO ◽  
LEANDRO FLÁVIO CARNEIRO ◽  
PAULO CÉSAR TIMOSSI ◽  
FLÁVIO HIROSHI KANEKO ◽  
...  

RESUMO – A resposta à adubação nitrogenada da cultura do milho é dependente do tipo de solo, sistema de cultivo, dose empregada e cultura antecessora. Nesse contexto, objetivou-se com o presente trabalho avaliar os efeitos dos resíduos vegetais de plantas de cobertura e da adubação nitrogenada no milho cultivado em sequência, sob sistema de plantio direto em consolidação no Cerrado. O experimento foi constituído de um fatorial 10 x 4, em delineamento de blocos casualizados e esquema de parcelas subdivididas, com quatro repetições. Os tratamentos das parcelas foram os resíduos do cultivo de dez plantas de cobertura (Cajanus cajan, Canavalia ensiformis, Crambe abyssinica, Crotalaria juncea, Crotalaria ochroleuca, Crotalaria spectabilis, Mucuna aterrima, Pennisetum glaucum, Raphanus sativus e Urochloa ruziziensis) e, nas subparcelas, foram testadas quatro doses de nitrogênio (0, 50, 100 e 150 kg ha-1 de N) em cobertura no estádio V5 da cultura do milho. Observou-se baixa resposta à adubação nitrogenada em cobertura, o que foi atribuído principalmente à ocorrência de déficit hídrico nas fases de florescimento e enchimento de grãos. De modo geral, as características agronômicas do milho foram mais influenciadas pela adubação nitrogenada do que pelas plantas de cobertura cultivadas anteriormente. O ganho médio de produtividade de grãos foi da ordem de 3,7 kg para cada 1 kg de N aplicado. O milho após Urochloa ruziziensis e Crambe abyssinica apresenta menor produtividade em relação ao uso das outras espécies de plantas de cobertura, independentemente da adubação nitrogenada.Palavras-chave: adubação verde, sistema conservacionista, veranico, Zea mays.COVER CROPS AND NITROGEN FERTILIZATION ON MAIZE GROWN IN NO-TILLAGE SYSTEM UNDER WATER DEFICIT ON CERRADO SOILABSTRACT - The response to nitrogen fertilization of the corn is dependent on the type of soil, cropping system, dose used and preceding crop. In this context, the goal of the present study was to evaluate the effects of cover crops residues and nitrogen fertilization on corn grown in succession, under no-tillage system in the Cerrado region. The experiment was arranged in a factorial 10 x 4, in a randomized complete block design and subdivided plot scheme, with four replications. The treatments of the plots were the residues of ten cover crops (Cajanus cajan, Canavalia ensiformis, Crambe abyssinica, Crotalaria juncea, Crotalaria ochroleuca, Crotalaria spectabilis, Mucuna aterrima, Pennisetum glaucum, Raphanus sativus and Urochloa ruziziensis) and in the subplots four nitrogen doses (0, 50, 100 and 150 kg ha-1 of N) were tested in the V5 stage of the corn. A low response to nitrogen fertilization was observed, which was mainly attributed to the occurrence of water deficit at the flowering and grain filling stages. In general, the agronomic characteristics of corn were more influenced by nitrogen fertilization than by the cover crops previously cultivated. The average gain of grain yield was of the order of 3.7 kg for each 1 kg ha-1 of N applied. Corn after Urochloa ruziziensis and Crambe abyssinica presented lower productivity compared to the use of other cover crop species, regardless nitrogen fertilization.Keywords: green manure, conservation tillage system, summer water deficit, Zea mays.


2019 ◽  
Vol 43 ◽  
Author(s):  
Martha Freire da Silva ◽  
Eduardo Fontes Araújo ◽  
Laércio Junio da Silva ◽  
Hugo Tiago Ribeiro Amaro ◽  
Luiz Antônio dos Santos Dias ◽  
...  

ABSTRACT Crambe is an oilseed plant whose oil is suitable for various industrial purposes, such as production of biodiesel, plastics, rubbers, and cosmetics. There are reports of the rusticity of this species and its potential for growth in arid and semi-arid environments, where water scarcity and soil salinity are common. However, studies regarding the tolerance of its seeds to these stresses and the physiological responses triggered during germination and seedling establishment under these conditions are incipient. The objective of this study was to evaluate the tolerance of crambe seeds to water deficit and salt stress during germination and early seedling development, as well as to investigate the role of antioxidant enzymes on tolerance to these conditions. The seeds were exposed to water and salt stresses and their performance was analyzed. Seed water content, imbibition rate, percentage and speed of germination, and the base water potential for seed germination were evaluated. In the seedlings, the following measurements were made: root and shoot length, fresh and dry matter of roots and shoots, moisture content, and activity of the enzymes superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX). Water deficit and salt stress reduce the water uptake rate of the seeds, the germination and growth of seedlings. The crambe seeds had higher tolerance to salt stress than to water deficit. Absorption of salt and the action of the SOD and CAT antioxidant enzymes are part of the tolerance mechanisms of crambe seeds to salt stress.


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