-In two simultaneous experiments, we evaluated the impact of brackish irrigation water and nitrogen (N) fertilization on the production of citrus (scion-rootstock combinations) and its associated gas exchanges. These experiments were conducted at the Campus of Federal University of Campina Grande, Brazil in a protected environment (shade screens on the sides) using drainage lysimeters. Experiment I used a randomized block design (3 replicates), in a 5 × 3 factorial arrangement, corresponding to five water salinity levels (0.6, 1.2, 1.8, 2. . For both experiments, gas exchanges and mean mass of fruits were evaluated at harvest. Gas exchanges were inhibited in plants under saline stress. Plants grafted with Common Rangpur lime showed greater production potential than did the other genotypes studied, even under brackish water conditions.
Gas exchanges and chlorophyll a fluorescence are ways to physiologically analyze the response of plants to salt stress. In this context, the present work was conducted between August and November 2016 in a greenhouse at the Federal University of Campina Grande (7°12’52” S, 35°54’24” W, mean altitude of 550 m), using bell pepper plants cv. All Big, exposed to levels of nutrient solution electrical conductivity (1.7, 3.7, 5.7, 7.7, 9.7 and 11.7 dS m-1) and cultivated in hydroponic system, spaced by 0.2 and 0.3 m, focusing on the analysis of gas exchanges and photochemical efficiency. The experimental design was completely randomized, in a 6 x 2 factorial scheme, with five replicates. Plant density influenced the sensitivity of the gas exchanges to salinity and, when reduced, mitigated its effects at higher salinity levels. Increasing plant density at high levels of electrical conductivity caused damage to the photosynthetic apparatus and even reduced the levels of efficiency of the photosystem II from 3.98 dS m-1.
TROCAS GASOSAS, PIGMENTOS CLOROPLASTÍDICOS E DANO CELULAR NA MAMONEIRA SOB DIFERENTES COMPOSIÇÕES CATIÔNICA DA ÁGUA GEOVANI SOARES LIMA1; HANS RAJ GHEYI2; REGINALDO GOMES NOBRE3; LAURIANE ALMEIDA DOS ANJOS SOARES4; PEDRO DANTAS FERNANDES5 E GUILHERME DE FREITAS FURTADO6 1Unidade Acadêmica de Engenharia Agrícola, Universidade Federal de Campina Grande, UFCG, Rua Aprígio Veloso, 882 -Universitário, Campina Grande, PB, geovanisoareslima@gmail.com2 Núcleo de Engenharia de Água e Solo, Universidade Federal do Recôncavo da Bahia, UFRB, Rua Rui Barbosa,710 -Centro, Cruz das Almas, BA. hans@pq.cnpq.br3Unidade Acadêmica de Ciências Agrárias, Universidade Federal de Campina Grande, UFCG, Rua Jario Vieira Feitosa, 1770, Bairro dos Pereiros, Pombal, PB, rgomesnobre@yahoo.com.br4Unidade Acadêmica de Engenharia Agrícola, Universidade Federal de Campina Grande, UFCG, Rua Aprígio Veloso, 882 -Universitário, Campina Grande, PB, laurispo.agronomia@gmail.com5Unidade Acadêmica de Engenharia Agrícola, Universidade Federal de Campina Grande, UFCG, Rua Aprígio Veloso, 882 -Universitário, Campina Grande, PB, pedrodantasfernandes@gmail.com6Unidade Acadêmica de Engenharia Agrícola, Universidade Federal de Campina Grande, UFCG, Rua Aprígio Veloso, 882 -Universitário, Campina Grande, PB, gfreitasagro@gmail.com 1 RESUMO Devido ao aumento na demanda de água tanto pela atividade agrícola quanto pelo abastecimento urbano e industrial e, considerando a escassez hídrica tanto quantitativa como qualitativamente, especialmente no semiárido do Nordeste Brasileiro, o uso de água salina na agricultura surge como alternativa para expansão das áreas irrigadas. Neste contexto, se avaliaram no presente estudo, as trocas gasosas, os pigmentos cloroplastídicos e o dano na membrana celular das plantas de mamoneira cv. BRS Energia, em função da irrigação com águas salinas de diferente natureza catiônica. O experimento foi desenvolvido em lisímetros de drenagem em condições de casa de vegetação, usando Argissolo Acinzentado Eutrófico de textura franco-arenosa, no município de Campina Grande-PB. Foram estudadas seis combinações catiônica da água (Testemunha; Na+; Ca2+; Na++Ca2+; K+ e Na++Ca2++Mg2+), no delineamento em blocos casualizados com quatro repetições, sendo cada parcela composta por cinco plantas. No tratamento testemunha, as plantas foram irrigadas com água de condutividade elétrica de 0,6 dS m-1 enquanto se utilizou nos demais tratamentos CEa de 4,5 dS m-1, obtida a partir de diferentes cátions, todos em forma de cloreto. A variação na condutividade elétrica da água promove maior efeito deletério sobre as trocas gasosas, os pigmentos cloroplastídicos e o dano na membrana celular das plantas de mamoneira cv. BRS Energia, na fase de florescimento, em comparação com a natureza catiônica da água; o potássio foi o cátion que proporciona os maiores valores para a taxa de assimilação de CO2 e eficiência instantânea do uso da água; O maior percentual de dano na membrana celular na mamoneira foi obtido nas plantas irrigadas com água potássica. Palavras-chave: Ricinnus communis L., estresse salino, fisiologia. LIMA, G. S. de.; GHEYI, H. R.; NOBRE, R. G.; SOARES, L. A. dos A.; FERNANDES, P. D.;FURTADO, G. de F.GAS EXCHANGES, CHLOROPLAST PIGMENTS AND CELL DAMAGE IN THE CASTOR BEAN PLANT UNDER DIFFERENT CATIONIC WATER COMPOSITIONS 2 ABSTRACT Due to the increase in water demand both for the agricultural activity and for urban as well as industrial supply and considering water scarcity both quantitatively and qualitatively, especially in semi-arid region of the Brazilian Northeast, the use of saline water in agriculture is an alternative for the expansion of irrigated areas. In this context, gaseous exchanges, chloroplast pigments and cell membrane damage in castor bean plants cv. BRS Energia, due to the irrigation with saline waters of a different cationic nature were evaluated. The experiment was carried out in drainage lysimeters under greenhouse conditions, using the Eutrophic Ultisol of sandy loam texture, in the city of Campina Grande, PB. Six cationic water combinations (Control, Na+, Ca2+, Na++ Ca2 +, K+ and Na++ Ca2++ Mg2+) were studied in the randomized block design with four replicates, each plot being composed of five plants. In the control treatment, the plants were irrigated with water of 0.6 dS m-1 electrical conductivity while in other treatments, ECw of 4.5 dS m-1, obtained from different cations, all in the form of chloride, were used. The variation in the electrical conductivity of the water promotes a greater deleterious effect on the gas exchange, chloroplast pigments and damage to the cell membrane of the castor bean plants cv. BRS Energia, in the flowering phase, compared to the cationic nature of water; potassium is the cation that provides the highest values for the CO2 assimilation rate and instantaneous efficiency of water use; the highest percentage of damage to the cell membrane of the castor bean plant is obtained in plants irrigated with water containing potassium. Keywords: Ricinnus communis L., salt stress, physiology.
The objective of this study was to evaluate chloroplast pigments and photochemical efficiency of West Indian cherry cv. BRS 366 Jaburu as a function of irrigation water salinity and potassium-phosphorus fertilization combinations in the second year of cultivation. The experiment was carried out in a protected environment in Campina Grande, Brazil. Treatments were distributed in randomized blocks, in a 5 × 4 factorial scheme, corresponding to five levels of electrical conductivity of irrigation water ECw (0.6, 1.4, 2.2, 3.0 and 3.8 dS m-1) and four combinations of potassium-phosphorus fertilization (100/100, 85/85, 60/60 and 45/45% of the K2O/P2O5 recommendation for the second year of cultivation 200 g of K2O and 120 g of P2O5 per plant per year) with three replicates. Irrigation with saline waters hampered the biosynthesis of chloroplast pigments and the photochemical efficiency of West Indian cherry cv. BRS 366 Jaburu in the second year of cultivation. Water salinity from 2.6 dS m-1 reduced the maximum fluorescence, variable fluorescence, and quantum efficiency of photosystem II of West Indian cherry plants cv. BRS 366 Jaburu. Fertilization with 60/60 and 85/85% of the K2O/P2O5 recommendation promotes an increase in the synthesis of chlorophylls a and b, respectively, in the first and second production cycles of the second year of cultivation. Supply of 85/85% of the K2O/P2O5 recommendation promoted an increase in maximum and variable fluorescence in plants subjected to water salinities of 0.6, 2.2, and 3.8 dS m-1 in the second cycle and reduced the initial fluorescence, regardless of the salinity level in the first and second production cycles of West Indian cherry.
R E S U M OCultivos consorciados representam benefícios econômicos e ambientais, por diversificar a produção na propriedade rural. Propôs-se, então, avaliar o rendimento e o grau de relacionamento entre características agronômicas da mamoneira em cultivo isolado e consorciado com feijão-caupi e gergelim. O experimento foi desenvolvido no período de março a novembro de 2011 em condições de campo, em Pombal, PB. Foram utilizados o delineamento em blocos casualizados em esquema fatorial 2 x 3 + 2, sendo 2 cultivares de mamona (IAC 2028 e BRS Nordestina), 3 sistemas de cultivo (monocultivo e consórcio com feijão-caupi ou gergelim) mais 2 tratamentos adicionais (feijão-caupi e gergelim em monocultivo) com 4 repetições. Avaliaram-se, também, as seguintes características: produção de grãos por planta (g), rendimento relativo (%), contribuição relativa das ordens dos racemos na produtividade total e estudo de correlações. Ocorreu em média maior contribuição de racemos secundários na produtividade total. O comprimento do racemo e o número de frutos por racemo são características altamente correlacionadas; dentre as culturas avaliadas a melhor opção de cultura companheira para o cultivo consorciado da mamoneira na região é o feijão-caupi.Yield and correlations of castor bean intercropped with cowpea and sesame in semiarid region of Paraíba A B S T R A C TIntercropping represents environmental and economic benefits due to production diversity on the farm. This study aimed to evaluate the yield and the degree of relationship between agronomic characteristics of two cultivars of castor bean as isolated crop and intercropped with cowpea and sesame. The experiment was carried out from March to November 2011 under field conditions at Pombal, in the State of Paraíba. The experimental design was a randomized block in factorial 2 x 3 + 2, using 2 castor bean cultivars (IAC 2028 and BRS Nordestina), 3 cropping systems (monoculture and intercropping with cowpea or sesame) plus 2 additional treatments (cowpea and sesame monoculture) with 4 replications. The following characteristics were evaluated: grain yield per plant (g), relative yield (%), the relative contribution of the orders of clusters in total productivity. On average there was a greater contribution of secondary clusters in total productivity. The length of the cluster and number of fruits in cluster are highly correlated. Between the intercrops evaluated the best choice of companion crops for intercropping of castor bean in the region is the cowpea. Palavras-chave:Ricinus communis L. sistema de manejo sequeiro
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