Morpho-anatomical and physiological aspects of Passiflora edulis Sims (passion fruit) subjected to flooded conditions during early developmental stages

Soil flooding is a phenomenon that reduces survival, growth and development of plants, and can cause a decrease in crop productivity. Passion fruit (Passiflora edulis Sims) is commercialized, has medicinal properties, and can benefit from irrigation when cultivated. However, there are no studies showing the effects of excess water in the soil on this plant. The objective of this study was to verify morpho-anatomical and physiological changes during early developmental stages of passion fruit seedlings exposed to different water levels in the soil. Seedlings were organized into three treatments: soil at field capacity, pre-submerged soil and flooded soil. After seven days, analyses of gas exchange, water potential, proline content and anatomical root sections were performed. The flooded soil had important effects on gas exchange and photosynthesis. No changes in water potential or proline content were verified among the different treatments. The pre-submerged and flooded treatments resulted in increased root diameter and thickness of apoplastic barriers and the cortex. Passion fruit exhibited physiological and anatomical responses that allowed it to survive in pre-submerged and flooded conditions

Allelochemical Activity of Eugenol-Derived Coumarins on Lactuca sativa L.

Coumarins are widely distributed substances in plant species that promote phytotoxic effects, allowing them to be exploited as herbicides less harmful to the environment, since many invasive species have demonstrated resistance to commercially available products. The derived coumarins used in this study had not been tested in plant models and their effect on plants was unknown. The objective of this study was to evaluate the phytotoxic action of these coumarins in bioassays with Lactuca sativa L., in order to select the most responsive substance whose toxicity was best elucidated by chromosomal complement and enzymatic antioxidant metabolism studies. From the phytotoxicity assays, coumarin 8-methoxy-2-oxo-6-(prop-2-en-1-yl)-2H-chromene-3-carboxylic acid (A1), reported here for the first time, was selected as the most responsive and caused a reduction in the following parameters: number of normal seedlings, fresh biomass, root length and shoot length. Subsequent studies demonstrated that this coumarin is cytogenotoxic due to damage caused to the cell cycle and the occurrence of chromosomal abnormalities. However, it did not interfere with antioxidant enzyme activity and did not cause lipid peroxidation. The changes caused by coumarin A1 described herein can contribute to better understanding the allelochemical actions of coumarins and the potential use of these substances in the production of natural herbicides

Morpho-anatomical and physiological aspects of Passiflora edulis Sims (passion fruit) subjected to flooded conditions during early developmental stages

Soil flooding is a phenomenon that reduces survival, growth and development of plants, and can cause a decrease in crop productivity. Passion fruit (Passiflora edulis Sims) is commercialized, has medicinal properties, and can benefit from irrigation when cultivated. However, there are no studies showing the effects of excess water in the soil on this plant. The objective of this study was to verify morpho-anatomical and physiological changes during early developmental stages of passion fruit seedlings exposed to different water levels in the soil. Seedlings were organized into three treatments: soil at field capacity, pre-submerged soil and flooded soil. After seven days, analyses of gas exchange, water potential, proline content and anatomical root sections were performed. The flooded soil had important effects on gas exchange and photosynthesis. No changes in water potential or proline content were verified among the different treatments. The pre-submerged and flooded treatments resulted in increased root diameter and thickness of apoplastic barriers and the cortex. Passion fruit exhibited physiological and anatomical responses that allowed it to survive in pre-submerged and flooded conditions. O alagamento no solo é um fenômeno que reduz a sobrevivência, o crescimento e o desenvolvimento de plantas, podendo ocasionar queda na produtividade quando essas são agricultáveis. O maracujazeiro (Passiflora edulis Sims) é uma frutífera comercial com propriedades medicinais cuja produção incentiva a irrigação; e não são encontrados estudos que apresentem efeitos do excesso de água no solo sobre estas plantas. O objetivo deste trabalho foi verificar alterações morfoanatômicas e fisiológicas no desenvolvimento inicial de plântulas de maracujazeiro expostas a diferentes níveis de água no solo. As plântulas foram organizadas em três tratamentos: solo com capacidade de campo, pré-submergido e alagado. Após sete dias, foram feitas análises de trocas gasosas, potencial hídrico, quantificação de prolina e cortes anatômicos de raízes. O solo alagado influencia as trocas gasosas e afeta negativamente a fotossíntese. Não houve alterações no potencial hídrico nem na quantificação de prolina entre os tratamentos. Os tratamentos pré-submergido e alagado apresentaram aerênquima e aumento no diâmetro das raízes e na espessura das barreiras apoplásticas e do córtex. O maracujazeiro apresentou alterações fisiológicas e anatômicas que permitiram sua sobrevivência em condições pré-submergidas e alagadas, o que significa que plântulas jovens dessa espécie suportam maiores quantidades de água no solo