ABSTRACT The increase of CO2 concentrations and temperatures may affect the plant development and production. This study aimed to evaluate the impact of the increased temperature and carbon dioxide concentration on the development of cowpea cultivars. The experiment was conducted in growth chambers, with control of CO2 and temperature. A completely randomized design was carried out, in a 4 x 3 x 2 factorial arrangement [cultivar x temperature (day/night) x CO2], with three replicates. The duration of the cowpea vegetative and reproductive phases was evaluated and, at the end of the experiment, the number of pods per plant, number of grains per pod, seed weight, shoot fresh and dry matter weight were quantified. Temperature affects the development of cowpea cultivars, and the temperatures of 29 ºC (day)/23 ºC (night) lead to a higher seed weight. The increase of CO2 leads to a higher number of pods and seeds and seed weight. The BRS Tapaihum cultivar presented the highest number of pods and seeds and seed weight. In addition, the temperatures of 32 ºC (day)/29 ºC (night) lead to a greater flower abortion in the BRS Pujante and BRS Tapaihum cultivars.

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Water deficit and high temperatures are abiotic factors that most limit plant growth and development. However, its effects depend on crop development stage and on stress duration and intensity. Thus, the objective of was to evaluate the development of cowpea subjected to water restriction in different phenological stages and to increase in air temperature. The experiment was conducted with the cultivar ‘Carijó’, in growth chambers, in a 4 x 3 x 2 factorial arrangement, corresponding to levels of water availability (25, 50, 75, and 100%,), phenological stages (vegetative, flowering and pod filling) and temperature regimes (T°1: 20-26-33 °C e T°2: 24.8-30.8-37.8 °C), respectively. Reduction of water availability in the vegetative and flowering stages caused decrease in grain production. The percentage of aborted flowers was higher in plants maintained under an increased temperature of +4.8 °C, with consequent reduction in grain production. Higher water availability values favored shoot and root dry mass production. Increase of 4.8 °C did not affect shoot and root dry mass but reduced water use efficiency by about 83%. The highest enzymatic activities of CAT, GPX and SOD were found in plants subjected to the temperature of +4.8 °C. Only APX showed lower enzymatic activity with increasing temperature. The cv. ‘Carijó’ is more sensitive to the 4.8 °C increase in air temperature than to water deficits.

Growing in a saline environment causes changes in important physiological processes that are directly related to plant growth and development. In this study we evaluated the effect of salinity on transpiration of sorghum plants in semi-arid conditions and found that the highest rates of transpiration were observed in the hottest hours of the day, between 10 a.m. and 3 p.m., with plants subjected to the saline environment having their transpiration reduced by up to 70% when compared to the non-saline environment. This behavior can be reflected in reductions in plant growth and development due to reduced water absorption by the roots, consequently causing an imbalance of nutrients in the plant due to low absorption rate and competition between nutrients and salts in the preferred routes of absorption in the roots.

O cultivo do sorgo em ambientes salinos provoca alterações importantes nos processos fisiológicos que são diretamente relacionados com a produtividade das plantas. O estudo objetivou avaliar o efeito da irrigação, com água salina, na produtividade, na atividade enzimática e nas trocas gasosas em variedades de sorgo granífero. Três variedades de sorgo foram submetidas a frações de lixiviação com água salina com condutividade elétrica de 4,19 dS m-1, em esquema de parcelas subdivididas. Foram avaliadas as variáveis distribuição de sais no solo, taxa de fotossíntese e transpiração, temperatura foliar, condutância estomática, atividade das enzimas catalase, ascorbato peroxidase e superóxido dismutase, e produtividade de biomassa da parte aérea. A aplicação de frações de lixiviação com água salina proporciona melhor distribuição dos sais no perfil do solo. Plantas de sorgo submetidas a irrigação com água salina apresentam redução nas trocas gasosas e no estado hídrico das células. A defesa antioxidativa foi ativada em plantas de sorgo cultivadas em ambientes salinos para evitar o acúmulo de espécies reativas de oxigênio, sendo que o sincronismo entre as enzimas refletiu em uma resposta positiva na produtividade das variedades 1011-IPA e Ponta Negra, com aumentos de 126% e 54%, respectivamente, na produtividade de grãos com a aplicação de lâminas de lixiviação. A utilização de água salina com condutividade elétrica média de 4,19 dS m-1 é uma alternativa viável para o cultivo irrigado das variedades 1011-IPA e Ponta Negra em Argissolo Vermelho Amarelo.

O mercado de frutas tropicais ou exóticas vem crescendo, fortemente, nos últimos anos, tanto no mercado interno, quanto no externo e a carambola se destaca como uma opção rentável de diversificação e uma alternativa de cultivo ao fruticultor. A cultura da carambola é originária da Ásia, no Brasil está em franca expansão, com pomares cujas informações sobre desempenho, qualidade e composição química são escassas. O presente trabalho teve como objetivo caracterizar física e quimicamente carambolas produzidas no vale do submédio São Francisco. Foi utilizada como matéria-prima carambolas, provenientes da cidade de Petrolina-PE. Os frutos, coletados aleatoriamente, com boas características externas de qualidade, se encontravam em três estádios de maturação: maduros, semi-maduros e verdes. Para a caracterização física utilizou-se uma balança semi analítica e um paquímetro, e com a polpa extraída destes frutos realizou-se a caracterização química, através das determinações do pH, sólidos solúveis totais (oBrix), sólidos totais, cinzas, e acidez total titulável. As polpas dos frutos maduros e semi-maduros apresentaram o teor de sólidos solúveis totais em torno de 8,3 °Brix e 7,2 °Brix, respectivamente, enquanto para a fruta verde o valor médio obtido foi de 5,5°Brix. Para as polpas dos frutos maduros, semi-maduros e verdes, foram encontrados valores médios de pH de 3,76, 3,62 e 3,59, o teor de sólidos totais de 89,7; 90,3 e 92,8% o percentual de cinzas de 0,55, 0,43 e 0,37% e acidez total titulável em torno de 0,35, 0,39 e 0,42% de ácido cítrico, respectivamente. A carambola produzida no vale do submédio São Francisco mostrou-se com um grande potencial de cultivo tanto para consumo in natura como para processamento.

Cowpea planting season is crucial for high yield and should comprise the period of the year that warrants the best climatic conditions for cowpea cultivation. Thus, the objective of this study was to evaluate the influence of water availability and temperature on the performance of cowpea cultivars. A greenhouse experiment was conducted using a 4 × 2 × 5 factorial arrangement, with four replications. Factors included four levels of soil moisture (25, 50, 75, and 100% of water holding capacity), two growing seasons (mild and hot), and five cowpea cultivars (Carijó, Itaim, Pujante, Rouxinol, and Tapahium). The number of pods and seeds per plant, seed production, water use efficiency, shoot dry mass, root dry mass, and physiological parameters were evaluated. Seed production was higher during the mild season than during the hot season and increased linearly with increasing soil water availability. Photosynthetic activity and transpiration were higher during the hot season than during the mild season, with their reduction under a water availability of 25% regardless of the growing season. Total chlorophyll content decreased with excess water. Regardless of water availability, temperature was the most limiting climatic factor for cowpea performance. Cultivars Carijó, Itaim, and Tapahium exhibited a lower reduction in productive potential when grown in the hot season.

Water deficit and high temperature limit agricultural productivity, affecting plant growth, development, and metabolism. Thus, the objective of this study was to evaluate the impact of the interaction between water deficit and temperature increase on cowpea production. The experiment was carried out with the cultivar BRS Rouxinol, in growth chambers, in a 4 × 2 factorial arrangement, being four soil water availability (25; 50; 75 and 100% of field capacity) and two daily temperature regimes (T°1: 20-26-33 °C and T°2: 24.8-30.8-37.8 °C). The increase in water availability favored an increase in shoot and root dry mass. The vegetative stage was prolonged in plants maintained at a temperature regime of 24.8-30.8-37.8 °C. The cowpea yield increased with higher water availability. The water availability of 90% was the one that provided the highest water use efficiency. The 4.8°C increase in air temperature promotes an increase in oxidative stress with lack of synchrony in the antioxidative defense system. The cultivar Rouxinol is sensitive to the increase in air temperature and water deficit. However, even with 100% water availability, there was no seed production with an increase in air temperature.