Climatic Variation on Gas Exchange and Chlorophyll a Fluorescence in Tabebuia roseoalba and Handroanthus heptaphyllus (Bignoniaceae)

Abstract: Climatic variation throughout the day influences the ecophysiological performance of plants at different growth stages and phases. Therefore, this work aimed to evaluate the effect of climatic variation on ecophysiological aspects of T. roseoalba and H. heptaphyllus at different hours of the day and indicate the ideal time for measuring ecophysiological variables in these species. The research was carried out in a greenhouse at the forest nursery of the Federal University of Paraíba, Campus II, in the municipality of Areia, Paraíba state, Northeastern Brazil. The experimental design was completely randomized, consisting of 10 evaluation times throughout the day (from 8 am to 5 pm), with 1 h hour interval between each evaluation. Temperature and air relative humidity inside and outside the greenhouse were evaluated to understand the effect on gas exchange (net assimilation rate of CO2, stomatal conductance, transpiration rate, internal concentration of CO2, and vapor-pressure deficit) and chlorophyll a fluorescence (initial, maximum, and variable fluorescence, photochemical quenching, and electron transport rate). Data were submitted to canonical correlation analysis and principal component analysis to verify the relationship between climatic and ecophysiological variables. For both species, higher correlation was found between internal and external relative humidity with all the ecophysiological variables analyzed, except for initial fluorescence. Thus, climatic factors influenced the photosynthetic performance of T. roseoalba and H. heptaphyllus plants, and 8 am to 9 am is indicated for carrying out ecophysiological evaluations in both species.

Morphometry, productivity and bromatological analisis of purple elephant grass according to nitrogen fertilization / Morphometry, productivity and bromatological analisis of purple elephant grass according to nitrogen fertilization

The objective was to evaluate the morphometric, productive and chemical aspects of purple elephant grass as a function of nitrogen fertilization. The treatments consisted of applying 0, 20, 40, 60, and 80 kg ha-1 of N, using a randomized block design, with five treatments and four replications. The following were evaluated: plant height, number, length and leaf mass, stem diameter and mass, leaf/stem ratio, production of green and dry mass, support capacity for dairy cows, crude protein, neutral detergent fiber and mineral matter. The data were submitted to analysis of variance and Tukey's test at 5% probability. The increase in N doses did not affect (p < 0.05) the morphometry of the purple elephant grass, however it positively stimulated the productivity, the animal support capacity and the bromatological components of the harvested material. The lack of response to nitrogen fertilization may be related to the edaphocilimatic conditions during the experiment and efficiency in the use of N of the variety used. The results demonstrate the high demand of the cultivar for N, actively interfering in the forage yield.

The objective was to evaluate the morphometric, productive and chemical aspects of purple elephant grass as a function of nitrogen fertilization. The treatments consisted of applying 0, 20, 40, 60, and 80 kg ha-1 of N, using a randomized block design, with five treatments and four replications. The following were evaluated: plant height, number, length and leaf mass, stem diameter and mass, leaf/stem ratio, production of green and dry mass, support capacity for dairy cows, crude protein, neutral detergent fiber and mineral matter. The data were submitted to analysis of variance and Tukey's test at 5% probability. The increase in N doses did not affect (p < 0.05) the morphometry of the purple elephant grass, however it positively stimulated the productivity, the animal support capacity and the bromatological components of the harvested material. The lack of response to nitrogen fertilization may be related to the edaphocilimatic conditions during the experiment and efficiency in the use of N of the variety used. The results demonstrate the high demand of the cultivar for N, actively interfering in the forage yield.

Morphometry, productivity and bromatological analisis of purple elephant grass according to nitrogen fertilization

The objective was to evaluate the morphometric, productive and chemical aspects of purple elephant grass as a function of nitrogen fertilization. The treatments consisted of applying 0, 20, 40, 60, and 80 kg ha-1 of N, using a randomized block design, with five treatments and four replications. The following were evaluated: plant height, number, length and leaf mass, stem diameter and mass, leaf/stem ratio, production of green and dry mass, support capacity for dairy cows, crude protein, neutral detergent fiber and mineral matter. The data were submitted to analysis of variance and Tukey's test at 5% probability. The increase in N doses did not affect (p < 0.05) the morphometry of the purple elephant grass, however it positively stimulated the productivity, the animal support capacity and the bromatological components of the harvested material. The lack of response to nitrogen fertilization may be related to the edaphocilimatic conditions during the experiment and efficiency in the use of N of the variety used. The results demonstrate the high demand of the cultivar for N, actively interfering in the forage yield.(AU)

Morphometry, productivity and bromatological analisis of purple elephant grass according to nitrogen fertilization / Morphometry, productivity and bromatological analisis of purple elephant grass according to nitrogen fertilization

The objective was to evaluate the morphometric, productive and chemical aspects of purple elephant grass as a function of nitrogen fertilization. The treatments consisted of applying 0, 20, 40, 60, and 80 kg ha-1 of N, using a randomized block design, with five treatments and four replications. The following were evaluated: plant height, number, length and leaf mass, stem diameter and mass, leaf/stem ratio, production of green and dry mass, support capacity for dairy cows, crude protein, neutral detergent fiber and mineral matter. The data were submitted to analysis of variance and Tukey's test at 5% probability. The increase in N doses did not affect (p < 0.05) the morphometry of the purple elephant grass, however it positively stimulated the productivity, the animal support capacity and the bromatological components of the harvested material. The lack of response to nitrogen fertilization may be related to the edaphocilimatic conditions during the experiment and efficiency in the use of N of the variety used. The results demonstrate the high demand of the cultivar for N, actively interfering in the forage yield.

The objective was to evaluate the morphometric, productive and chemical aspects of purple elephant grass as a function of nitrogen fertilization. The treatments consisted of applying 0, 20, 40, 60, and 80 kg ha-1 of N, using a randomized block design, with five treatments and four replications. The following were evaluated: plant height, number, length and leaf mass, stem diameter and mass, leaf/stem ratio, production of green and dry mass, support capacity for dairy cows, crude protein, neutral detergent fiber and mineral matter. The data were submitted to analysis of variance and Tukey's test at 5% probability. The increase in N doses did not affect (p < 0.05) the morphometry of the purple elephant grass, however it positively stimulated the productivity, the animal support capacity and the bromatological components of the harvested material. The lack of response to nitrogen fertilization may be related to the edaphocilimatic conditions during the experiment and efficiency in the use of N of the variety used. The results demonstrate the high demand of the cultivar for N, actively interfering in the forage yield.

Production of watermelon irrigated with saline water in mulched Entisol with potassium fertilization / Produção de melancieira irrigada com água salina em Neossolo com cobertura morta e adubação potássica

The adjustment in the growing season associated with cultural practices can mitigate the negative effects of salinity on crop production. In this context, the objective of this study was to evaluate the production components of watermelon cv. Crimson Sweet under the effects of irrigation with saline water, soil cover and potassium doses in crops during dry and rainy seasons. The treatments were arranged in a split plot with 2 x 2 x 4 scheme, with the electrical conductivity of the irrigation water (0.3 and 3.0 dS m-1) in the main plot, and the combinations between soil mulch (without and with) and doses of potassium (0, 40, 80 and 120 kg ha-1 of K2 O) in the subplots, distributed in randomized blocks. Final stand, number of fruits per plant, average fruit weight, production per plant and yield were evaluated. The data were subjected to analysis of variance and potassium doses were evaluated by regression. In the rainy season, watermelon was more productive than in the dry season even under irrigation, with higher number of fruits and production per plant and yield. Irrigation using water with electrical conductivity of 3.0 dS m-1 should be used with moderation in watermelon crop, as it did not compromise yield. Potassium chloride application is not recommended in soil with intermediate potassium content, because it reduced the number of fruits per plant and yield. The use of mulch is recommended in watermelon cultivation, since it increased the number of fruits and production per plant.(AU)

A adequação na época de cultivo associada às práticas culturais pode mitigar os efeitos negativos da salinidade à produção agrícola. Nesse sentido, objetivou-se com esta pesquisa avaliar componentes de produção de melancia cv. Crimson Sweet sob efeitos da irrigação com água salina, cobertura do solo e doses de potássio nos cultivos em épocas de estiagem e chuvosa. Os tratamentos foram organizados em parcela subdividida no esquema 2 x 2 x 4, sendo a condutividade elétrica da água de irrigação (0,3 e 3,0 dS m-1) a parcela principal, e as combinações entre cobertura morta do solo (sem e com) e doses de potássio (0, 40, 80 e 120 kg ha-1 de K2 O) as subparcelas, distribuídos em blocos casualizados. Avaliou-se o estande final, número de frutos por planta, massa média dos frutos, produção por plantas e produtividade. Os dados foram submetidos as análises de variância e as doses de potássio avaliadas por regressão. Na época chuvosa, a melancieira foi mais produtiva que no período de estiagem mesmo sob irrigação, com maior número de frutos, produção por planta e maior produtividade. A irrigação com água de 3,0 dS m-1 de condutividade elétrica pode ser recomendada com moderação na cultura da melancieira, visto que não comprometeu a produtividade. A aplicação de cloreto de potássio não é recomendada em solo com teor médio de potássio, pois reduziu o número de frutos por planta e a produtividade. O uso de cobertura morta é indicado no cultivo de melancieira, uma vez que aumentou o número de frutos e a produção por planta.(AU)

Morphometric and productive characteristics of sorghum genotypes for forage production in the Brazilian semi-arid / Características morfométricas e produtivas de genótipos de sorgo para produção de forragem no semiárido brasileiro

This study agronomically evaluated 14 sorghum genotypes in the Brazilian semi-arid region. A randomized complete block design, with the treatments represented by sorghum genotypes and three replicates, was used. The dry matter (DM), plant height (PH), number of live leaves, fresh matter production (FMP), dry matter production (DMP), leaf blade (LB), stem, panicle (PAN), dead material, water accumulation (WA), efficiency of rainwater use (ERU) and carrying capacity (SC) were measured. There was an effect of genotype among all the variables. The genotype with the highest percentage of DM was BRS 655 (26.42%). The genotypes BRS 655, BRS 506, B1141340, 13F04 (1141572) and PONTA NEGRA produced the most FMP, with values of 48,517, 48,500, 44,879, 44,788 and 43,549 kg/ha, respectively. Not only did the genotypes BRS 655, B1141340, 13F04 (1141572), BRS 506 and PONTA NEGRA present the highest DMP, with values of 12,426, 10,344, 9,778, 9,756 and 9,176 kg/ha, respectively, but also the highest values for ERU, WA and SC. There was a significant positive correlation between productive variables (FMP with DMP, PH, ERU and WA) and a nonsignificant negative correlation between morphometric variables (FMP with LB and PAN). A hierarchical formation of four groups was observed, with groups I and III composed of the most productive genotypes. BRS 655 can be recommended for cultivation since this genotype has desirable agronomic characteristics.

Objetivou-se avaliar agronomicamente 14 genótipos de sorgo no semiárido brasileiro. Utilizou-se delineamento experimental em blocos casualizados com os tratamentos representados pelos genótipos de sorgo e três repetições. Foram avaliadas matéria seca (MS), altura da planta (AP), número de folhas vivas, produção de matéria verde (PMV), produção de matéria seca (PMS), lamina foliar (LF), colmo, panícula (PAN), material morto (MM), acúmulo de água (ACA), eficiência do uso da chuva (EUC) e capacidade de suporte (CS). Houve efeito entre todas as variáveis. O genótipo com maior percentual de MS foi BRS 655 (26,42%). Houve efeito para PMV, os genótipos com maior produção foram BRS 655, BRS 506, B1141340, 13F04(1141572) e PONTA NEGRA, com valores de 48.517, 48.500, 44.879, 44.788, 43.549 kg/ha. Os genótipos que apresentaram maior PMS foram BRS 655, B1141340, 13F04(1141572), BRS 506 e PONTA NEGRA, com valores de 12.426, 10.344, 9.778, 9.756 e 9.176 kg/ha, respectivamente e também apresentaram maiores valores para EUC, ACA e CS. Houve correlação positiva significativa entre variáveis produtivas (PMV com PMS, AP, EUC e ACA) e correlação negativa não significativa (PMV com LF e PAN) com variáveis morfométricas. Houve formação hierárquica de quatro grupos, sendo os grupos I e III compostos pelos genótipos mais produtivos. O genótipo BRS 655 pode ser recomendado para o cultivo, pois possui características agronômicas desejáveis.

Morphometric and productive characteristics of sorghum genotypes for forage production in the Brazilian semi-arid / Características morfométricas e produtivas de genótipos de sorgo para produção de forragem no semiárido brasileiro

This study agronomically evaluated 14 sorghum genotypes in the Brazilian semi-arid region. A randomized complete block design, with the treatments represented by sorghum genotypes and three replicates, was used. The dry matter (DM), plant height (PH), number of live leaves, fresh matter production (FMP), dry matter production (DMP), leaf blade (LB), stem, panicle (PAN), dead material, water accumulation (WA), efficiency of rainwater use (ERU) and carrying capacity (SC) were measured. There was an effect of genotype among all the variables. The genotype with the highest percentage of DM was BRS 655 (26.42%). The genotypes BRS 655, BRS 506, B1141340, 13F04 (1141572) and PONTA NEGRA produced the most FMP, with values of 48,517, 48,500, 44,879, 44,788 and 43,549 kg/ha, respectively. Not only did the genotypes BRS 655, B1141340, 13F04 (1141572), BRS 506 and PONTA NEGRA present the highest DMP, with values of 12,426, 10,344, 9,778, 9,756 and 9,176 kg/ha, respectively, but also the highest values for ERU, WA and SC. There was a significant positive correlation between productive variables (FMP with DMP, PH, ERU and WA) and a nonsignificant negative correlation between morphometric variables (FMP with LB and PAN). A hierarchical formation of four groups was observed, with groups I and III composed of the most productive genotypes. BRS 655 can be recommended for cultivation since this genotype has desirable agronomic characteristics.(AU)

Objetivou-se avaliar agronomicamente 14 genótipos de sorgo no semiárido brasileiro. Utilizou-se delineamento experimental em blocos casualizados com os tratamentos representados pelos genótipos de sorgo e três repetições. Foram avaliadas matéria seca (MS), altura da planta (AP), número de folhas vivas, produção de matéria verde (PMV), produção de matéria seca (PMS), lamina foliar (LF), colmo, panícula (PAN), material morto (MM), acúmulo de água (ACA), eficiência do uso da chuva (EUC) e capacidade de suporte (CS). Houve efeito entre todas as variáveis. O genótipo com maior percentual de MS foi BRS 655 (26,42%). Houve efeito para PMV, os genótipos com maior produção foram BRS 655, BRS 506, B1141340, 13F04(1141572) e PONTA NEGRA, com valores de 48.517, 48.500, 44.879, 44.788, 43.549 kg/ha. Os genótipos que apresentaram maior PMS foram BRS 655, B1141340, 13F04(1141572), BRS 506 e PONTA NEGRA, com valores de 12.426, 10.344, 9.778, 9.756 e 9.176 kg/ha, respectivamente e também apresentaram maiores valores para EUC, ACA e CS. Houve correlação positiva significativa entre variáveis produtivas (PMV com PMS, AP, EUC e ACA) e correlação negativa não significativa (PMV com LF e PAN) com variáveis morfométricas. Houve formação hierárquica de quatro grupos, sendo os grupos I e III compostos pelos genótipos mais produtivos. O genótipo BRS 655 pode ser recomendado para o cultivo, pois possui características agronômicas desejáveis.(AU)