Gas exchanges and chlorophyll content in green pepper plants under bio-fertilization and times of application

This study aimed to determine the gas exchange and the chlorophyll content of green pepper plants under doses and times of application of bio-fertilizers based on manure and enriched organic compost. Two experiments were carried out simultaneously with applications of bio-fertilizers prepared from manure and enriched organic compost, one using cattle manure (CBF) and the other sheep manure (SBF). For these, four doses of biological fertilizers (100, 200, 300 and 400 dm³ ha-1), three application times (0, 30 and 60 days after transplantation - DAT) and absolute control, referring to the absence of fertilization, were used. treatments. were arranged in a randomized block design, totaling 13 treatments. The variables evaluated were: the relative chlorophyll a, b and total content; liquid photosynthesis (A); stomatal conductance (gs); internal CO2 concentration (Ci); instant carboxylation efficiency (iCE - A/Ci); transpiration rate (T); intrinsic water use efficiency (iWUE - A/gs); and water use efficiency (WUE - A/E). Gs, A and T, showed significant effect at 60 DAT with the application of SBF and Ci at 30 DAT with CBF. The dose of 400 dm³ ha-1 of SBF provided greater gas results, and the doses of 200 and 300 dm³ ha-1 of CBF promoted a greater Ci, greater stomatal conductance, greater liquid photosynthesis and better water use efficiency, which results in a greater plant fresh weight at the time of flowering induction.

Photosynthesis of Physalis peruviana under different densities of photons and saline stress

Physalis peruviana L. is a solanacea that has been gaining prominence due to its fruits presenting good acceptance in the national and international market. However, several abiotic factors, such as salinity, can cause physiological disturbances in plants, and these changes may be of greater or lesser intent according to species. Therefore, the objective of the present work was to evaluate the physiological behavior of P. peruviana submitted to different fluxes of photosynthetically active photons (PPFD) and saline stress. The experimental design was a randomized block design with three saline levels (ECw) (0.5, 2.75 and 5.00 dS m-1) with four replications. Gas exchange measurements were performed with a portable infrared gas analyzer. Liquid CO2 assimilation, stomatal conductance, internal CO2 concentration, water use efficiency and instantaneous carboxylation efficiency were measured. Data were subjected to analysis of variance by F test and in cases of significance applied to regression analysis. The increase in PPFD provided reductions in stomatal conductance up to the density of approximately 400 µmol m-2s-1, being more pronounced in ECw of 2.75 and 5.0 dS m-1. The maximum CO2 assimilation rates in the three salinities are different according to the PPFD. The salinity of irrigation water reduced the quantum efficiency of photosynthesis in P. peruviana plants.

Physiological changes in Solanum lycopersicum L. in the presence of root-knot nematodes and salicylic acid / Alterações fisiológicas em Solanum lycopersicum L. na presença de nematóides das galhas e ácido salicílico

Nematodes of the genus Meloidogyne spp. are one of the tomato culture's main pathogens. According to their soil infestation level, physiological changes may occur. Consequently, it is extremely important to employ given products to minimize their effect. A feasible option is the salicylic acid, a phytohormone that can induce into resistance due to its ability to increase the production level of some pathogenicity proteins. Therefore, the purpose hereof was to assess the effect of salicylic acid on the physiology of tomato plants subject to different populational densities of Meloidogyne javanica. The design employed was one of randomized blocks, in an incomplete factorial scheme, using the Box Central Compound (BCC) matrix with five nematode populational densities (PD) (0; 5815; 20000; 34184; and 40000 eggs per plant) and five salicylic acid doses (0.0; 0.29; 1.0; 1.71; and 2.0 mM), with four repetitions and two plants per experimental patch. The gas exchanges, fluorescence, and chlorophyll levels were evaluated 45 days after the transplant and soil infestation. The data were submitted for analysis of variance through the F test and, in the significance cases, the polynomial regression analysis was performed. For stomatal conductance, a greater reduction was seen at the PD of 21755 eggs per plant, a fact that might have decreased the liquid assimilation of CO2 and the efficiency of carboxylation. The salicylic acid (SA) affected the CO2 liquid assimilation and the efficiency of carboxylation. The infestation of M. javanica in tomato plants negatively affected the gas exchange and the chlorophyll levels because the SA application did not mitigate the negative effect thereof.

Os nematoides do gênero Meloidogyne spp. são um dos principais patógenos na cultura do tomate, podendo causar alterações fisiológicas em função do nível de infestação do solo. O uso de produtos que minimize seus efeitos é de suma importância, nesse sentido, o ácido salicílico pode ser uma alternativa viável, visto que, esse fitormônio pode induzir a resistência devido à capacidade de proporcionar um aumento na produção de algumas proteínas de patogenicidade. Com isso, objetivou-se avaliar o efeito do ácido salicílico na fisiologia do tomateiro submetido a diferentes densidades populacionais de Meloidogyne javanica. O delineamento utilizado foi o de blocos casualizados, em esquema fatorial incompleto, utilizando-se a matriz Composto Central de Box (CCB) com cinco densidades populacionais (DP) de nematoides (0; 5815; 20000; 34184 e 40000 ovos por planta) e cinco doses de ácido salicílico (0,0; 0,29; 1,0; 1,71 e 2,0 mM), com quatro repetições e duas plantas por parcela experimental. Foram avaliadas as trocas gasosas, fluorescências e índices de clorofilas aos 45 dias após o transplantio e infestação do solo. Os dados foram submetidos à análise de variância pelo teste F e nos casos de significância foi realizada análise de regressão polinomial. Para a condutância estomática, observou-se uma maior redução na DP de 21755 ovos por planta, fato que pode ter ocasionado reduções na assimilação líquida de CO2 e na eficiência de carboxilação. O ácido salicílico (AS) influenciou na assimilação líquida de CO2 e eficiência de carboxilação. A infestação por M. javanica em plantas de tomateiro influenciou negativamente nas trocas gasosas e nos teores de clorofila, sendo que a aplicação do AS não atenuou os efeitos negativos desses patógenos.

Estimation of leaf area of Erythroxylum citrifolium from linear leaf dimensions / Estimativa da área foliar de Erythroxylum citrifolium a partir de dimensões lineares da folha

Erythroxylum citrifolium is a neotropical plant species recorded in all regions of Brazil. Determining leaf area is of fundamental importance to studies related to plant propagation and growth. The objective was to obtain an equation to estimate the leaf area of E. citrifolium from linear dimensions of the leaf blade (length and width). A total of 200 leaf blades were collected in Parque Estadual Mata do Pau-Ferro in the municipality of Areia, state of Paraíba, Northeast Brazil. The models evaluated were: linear, linear without intercept, quadratic, cubic, power and exponential. The best model was determined by the criteria of: high coefficient of determination (R²), low root mean square error (RMSE), low Akaike information criterion (AIC), high Willmott concordance index (d) and a BIAS index close to zero. All of the models constructed satisfactorily estimated the leaf area of E. citrifolium, with coefficients of determination above 0.9050, but the power model using the product between length and width (L*W) y = 0.5966 * LW1.0181 was the best, with the highest values of R² and d, low values of RMSE and AIC, and a BIAS index closest to zero.

Erythroxylum citrifolium é uma espécie de planta neotropical com registros em todas as regiões do Brasil. A determinação da área foliar é de fundamental importância em estudos relacionados a propagação e crescimento vegetal. O objetivo foi obter uma equação que permita estimar a área foliar de E. citrifolium a partir de dimensões lineares do limbo foliar (comprimento e largura). Foram coletados 200 limbos foliares no Parque Estadual Mata do Pau-Ferro, Areia, Paraíba, Nordeste do Brasil. Os modelos empregados foram: linear, linear sem intercepto, quadrático, cúbico, potencial e exponencial. Os critérios utilizados para escolher o melhor modelo, teve como base o maior coeficiente de determinação (R²), menor raiz do quadrado médio do erro (RMSE), menor critério de informação de Akaike (AIC), maior índice de concordância de Willmott (d) e índice BIAS mais próximo de zero. Todos os modelos construídos podem estimar satisfatoriamente a área foliar de E. citrifolium, com coeficientes determinação acima de 0,9050, porém o modelo potencial utilizando o produto entre comprimento e largura (L*W) y = 0,5966 * LW1,0181 é o mais indicado, com os maiores valores de R² e d, menores valores de RMSE e AIC, e índice BIAS mais próximo de zero.

Leaf area estimation for Psychotria carthagenensis and Psychotria hoffmannseggiana as a function of linear leaf dimensions

Determining leaf area is important for studies involving plant growth and development. The aim of the present study was to obtain models for estimating leaf area of Psychotria carthagenensis and Psychotria hoffmannseggiana using linear measurements of leaf blades (length and width). Two hundred leaf blades of each species were collected in Parque Estadual Mata do Pau-Ferro in the municipality of Areia, Paraíba, Northeast Brazil. The equations evaluated for producing potential models included the following: linear, quadratic, potential and exponential. The criteria used to determine the best model(s) were as follows: high coefficient of determination (R²), low root-mean-square error (RMSE), low Akaike information criterion (AIC), high Willmott concordance index (d) and a BIAS ratio close to zero. All evaluated models satisfactorily estimated leaf area for the two species, but the equation ŷ = 0.6373 * LW0.9804 was the most appropriate for P. carthagenensis, while ŷ = 0.6235 * LW0.9712 was the most appropriate for P. hoffmannseggiana.

Temperatures and substrates for germination and vigor ofErythroxylum pauferrense Plowman seeds

Erythroxylum pauferrense is an endemic understory plant species of the Northeast Region of Brazil. The species is of great importance to the region and so ecophysiological studies are needed for its preservation. The objective of the present study was to determine the best substrates and temperatures for testing germination and seed vigor of E. pauferrense. An experiment was performed comprising a completely randomized design in a 5 x 4 factorial scheme, with five temperature regimes (20, 25, 30, 35°C constant and 20-30°C alternating) and four types of substrates (paper, vermiculite, sand and commercial substrate). The following characteristics were evaluated: germination percentage, first germination count, germination speed index, mean germination time, seedling length and dry mass (root and shoot). Paper and vermiculite substrates combined with constant temperatures of 20, 25, 30 and alternated between 20-30°C, provide greater seed germination and vigor while 35°C reduces seed physiological quality.

Morphophysiological evaluation of Bauhinia divaricata L. (Fabaceae) plants at different water regimes / Avaliação morfofisiológica em plantas de Bauhinia divaricata L. (Fabaceae) em diferentes regimes hídricos

The pata-de-vaca (Bauhinia divaricata L.) tree is a species widely distributed in Brazil, it has a high ornamental and economic value. Its leaves are used in renal inflammations, such as diuretic, hypoglycemic, being considered a medicinal plant of popular use. The research was carried out in a greenhouse belonging to the Laboratório de Ecologia Vegetal, at the Centro de Ciências Agrárias (CCA), from Universidade Federal of Paraíba (UFPB). The objective was to evaluate the morphophysiological characteristics of B. divaricata plants at different water regimes. The experimental design was completely randomized with five water treatments 1 (100% control), 2 (80%), 3 (60%), 4 (40%) and 5 (20%) of the container capacity. The height, number of leaves and stem diameter were evaluated weekly. At the end of the experiment the plants had their organs separated and taken to the greenhouse to obtain the dry matter of the leaves, stem, roots and total dry matter, and also, biomass allocation in the leaves, stem and roots. Plant height did not differ statistically between the treatments. The number of leaves, diameter, leaf, stem and root allocation and root and shoot dry matter were higher under water availability (100% of container capacity). For the production of B. divaricata L. seedlings water regime should be 100% and 80% of the container capacity, but the seedlings grow satisfactorily.

A pata-de-vaca (Bauhinia divaricata L.) é uma espécie arbórea, amplamente distribuída no Brasil, de alto valor ornamental e econômico. Suas folhas são utilizadas nas inflamações renais, como diuréticas, hipoglicemiantes, sendo considerada uma planta medicinal de uso popular. A pesquisa foi desenvolvida em casa de vegetação pertencente ao Laboratório de Ecologia Vegetal, Centro de Ciências Agrárias (CCA), Universidade Federal da Paraíba (UFPB). O Objetivo foi avaliar as características morfofisiológicas em plantas de Bauhinia divaricata em diferentes regimes hídricos. O delineamento experimental foi inteiramente casualizado com cinco tratamentos hídrico 100%, 80%, 60%, 40% e 20% da capacidade de pote. Avaliou-se, semanalmente a altura, número de folhas e diâmetro do caule. Ao final do experimento as plantas tiveram seus órgãos separados e levados à estufa para obtenção da matéria seca das folhas, caule, raízes e massa seca total, e ainda, alocação de biomassa nas folhas, caule e raízes. A altura de plantas não diferiu estatisticamente entre os tratamentos, o número de folhas, diâmetro, alocação de folhas, caules e raízes e massas seca da raiz e parte aérea foram maiores sob maior disponibilidade de água (100% da capacidade do recipiente). Para a produção de mudas de B. divaricata L. o regime hídrico deve ser de 100% e 80% da capacidade do recipiente, porém as mudas crescem satisfatoriamente.

Morpho-physiological analyses of Allamanda blanchetii A. DC. seedlings under water deficit / Análises morfo-fisiológicas em plantas de Allamanda blanchetii A. DC sob déficit hídrico

The Allamanda blanchetii belongs to the Apocynaceae family, being an ornamental species popularly known as allamanda-roxa and is endemic to the Caatinga. The aim of this research was to evaluate the growth, gas exchange, relative water content, and stomatal density of A. blanchetii under water stress conditions. The experimental design was completely randomized with six levels of the maximum water holding capacity (MWHC) (100%, 80%, 60%, 40%, and 20%) with eight replications. Weekly, it was performed the evaluations of plant height and number of leaves. The results for water stress treatment in the A. blanchetii plants show that they develop better in the water levels of 100% and 80% of the MWHC, without presenting significant morphological and physiological changes. In turn, 20% of the MWHC does not allow the survival of the A. blanchetii plants. The water restriction negatively interfered in the gas exchange in the treatment of 60% and 40% of the MWHC. Therefore, it can be concluded that the A. blanchetii plants grow satisfactorily in 100% and 80% of the MWHC, ensuring the growth and survival during the drought period. The water availability to which the plants were submitted does not influence the total chlorophyll and relative water content of leaves. Gas exchanges are adversely affected at levels of water availability below 80% of the MWHC.

Allamanda blanchetii pertence à família Apocynaceae, é uma espécie ornamental, conhecida popularmente como allamanda-roxa, endêmica da Caatinga. O objetivo da pesquisa foi avaliar o crescimento, trocas gasosas, conteúdo relativo de água e densidade estomática de A. blanchetii sob condições de estresse hídrico. O delineamento experimental foi inteiramente casualizado, com seis capacidade máxima de retenção de água tratamentos hídricos (100%, 80%, 60%, 40% e 20%) com oito repetições. Os resultados obtidos sobre o déficit hídrico aplicado, as plantas de A. blanchetii se desenvolvem com níveis de água de 100% e 80% da CMRA, sem apresentar modificações morfológicas e fisiológicas significativas enquanto que com de 20% da CMRA não houve a sobrevivência de plantas. A restrição hídrica interferiu negativamente nas trocas gasosas, nos tratamentos de 60% e 40% CMRA. Portanto pode-se concluir que as plantas de A. blanchetii crescem satisfatória sob 100% e 80% CMRA garantindo a sua sobrevivência e crescimento durante a seca. A clorofila total e o teor relativo de água na folha das plantas não foram influenciados pelos regimes hídricos a que foram submetidas. As trocas gasosas são negativamente afetadas em níveis de disponibilidade hídrica abaixo de 80% da CMRA.