ABSTRACT
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.
Subject(s)
Photosynthesis , Photons , Physalis/physiology , Salinity , Salt StressABSTRACT
Water scarcity and water quality is a subject of constant debate around the world, with the accumulation of salts in water and on soils causing a negative impact on food production, man and herds, especially in the arid and semi-arid regions. The use of bovine manure biofertilizers that potentiate the use of brackish water, normally restricted in agriculture due to its salinity, has been suggested for seedling formation and crop production, including jackfruit plants. An experiment was carried out from October/2012 to February/2013, in a protected environment, at Agrarian Sciences Center, Federal University of Paraíba, Areia county, Paraíba State, Brazil, to evaluate the effects of saline water and bovine biofertilizer chemically enriched with gypsum, cow's milk and molasses. The experimental design was completely randomized, with five replications of a plant, in a factorial scheme 5 × 2, corresponding at values of electrical conductivity of the water of 0.5, 1.0, 2.0, 3.0 and 4.0 dS m-1 substrate with and without bovine biofertilizer. Measurements were made of substrate salinity, height of growth, stem diameter, length mean root, leaf area, leaf area ratio, and total dry mass (root, shoots and leaves). The biofertilizer enriched with cow's milk, sugar cane molasses and agricultural gypsum increased the salinity of the soil; however, it attenuated the negative effects of the salts during establishment of jackfruit seedlings, to 95 days after emergence. All the growth variables studied were higher for seedlings developed in substrate with bovine biofertilizer chemically enriched.
A escassez e a qualidade da água são assuntos de constante debate em todo o mundo, com o acúmulo de sais na água e nos solos, causando um impacto negativo na produção de alimentos, homem e rebanhos, especialmente nas regiões áridas e semiáridas. O uso de biofertilizante de esterco bovino que possibilita o uso de água salobra, normalmente restrita à agricultura devido à salinidade, tem sido sugerido para formação demudas e produção agrícola, inclusive de jaqueira. Um experimento foi desenvolvido entre outubro de 2012 e fevereiro de 2013, em ambiente protegido, no Centro de Ciências Agrárias, da Universidade Federal da Paraíba, Areia, Paraíba, Brasil, para avaliar os efeitos da água salina e biofertilizante bovino enriquecido quimicamente com calcário, leite de vaca e melaço. O delineamento experimental foi inteiramente casualizado, com cinco repetições e uma planta, em esquema fatorial 5 × 2. Água com condutividade elétrica de 0,5, 1,0, 2,0, 3,0 e 4,0 foram aplicadas no substrato com e sem biofertilizante bovino. Foi avaliada a salinidade do substrato, crescimento em altura, diâmetro caulinar, crescimento da raiz principal, área foliar, razão de área foliar e massa seca total (raiz, parte aérea e folhas). O biofertilizante enriquecido com leite de vaca, melaço de cana-de-açúcar e gesso agrícola aumentou a salinidade do solo, no entanto, atenuou os efeitos negativos da salinidade durante o estabelecimento das mudas de jaqueira, aos 95 dias após a emergência. Todas as variáveis estudadas foram maiores nas mudas que cresceram no substrato com biofertilizante enriquecido quimicamente.