Phytotoxic potential of Senna occidentalis (L.) Link extracts on seed germination and oxidative stress of Ipê seedlings

Abstract

Senna occidentalis is an invasive plant producing a series of allelochemicals that might inhibit the development of other plants. The objective of this study was to assess the phytotoxic effect of S. occidentalis extracts on the germination, development and antioxidant defence of the native species Tabebuia chrysotricha, T. pentaphylla, T. roseoalba and Handroanthus impetiginosus (Ipê species).• We evaluated the effects of chemicals extracted from S. occidentalis on the germination rate, germination speed index (GSI) and biometric parameters of the test species under controlled conditions. The effect of the extracts on the pigment content, amount of H 2 O 2 and malondialdehyde (MDA), and the activity of the antioxidant enzymes in roots and leaves were also tested.• Alkaloids, coumarins, phenols, saponins, free steroids and condensed tannins were present in all extracts of S. occidentalis, while catechins were present only in leaf and stem extracts. Stem and root extracts caused a growth reduction in all Ipê species and total inhibition of seed germination in T. chrysotricha and T. roseoalba. All target species showed an increase in H 2 O 2 and MDA in radicles and leaves. Oxidative stress contributed strongly to the morphological changes, such as seed blackening, thinning and darkening of radicle tips and reduction of biomass allocation in all Ipê species.

Assessment of Allelopathic Potential of Senna garrettiana Leaves and Identification of Potent Phytotoxic Substances

“…Such different degrees of inhibition of the test plants may be related to the bioactive compounds exhibiting increased inhibitory effects on physiological processes as the concentration increased. Our results are consistent with previous research, which reported that Senna species have inhibitory activity, such as extracts of S. obtusifolia and S. occidentalis causing the inhibition of the seed germination and growth of plant species [7,8]. Moreover, the unequal susceptibility of the tested species to the extracts could be due to inherent differences in the biochemicals involved in the process [34].…”

“…Sandwith with increased contents of hydrogen peroxide and malondialdehyde in the radicles and leaves. The phytotoxic compounds contained in Senna occidentalis (L.) include alkaloids, coumarins, phenols, saponins, free steroids, and tannins [8]. Some phytochemical features that make the extract a potential natural herbicide include its similar mechanisms of action to synthetic herbicides; total or partial solubility for easy application without surfactants; and chemical structures with high oxygen and nitrogen contents that are environmentally friendly, reduce the environmental half-life, and prevent accumulation in the soil [9].…”

Differential activity of wheat antioxidant defense system and alterations in the accumulation of osmolytes at different developmental stages as influenced by marigold (Tagetes erecta L.) leachates

“…(2007) , while working on mangrove plants, noticed that the lipid peroxidation level in leaves may serve as a biomarker in Bruguiera gymnorrhiza whereas POD activity may be used as heavy metal biomarker for Kandelia candel . The enhancement in lipid peroxidation has also been reported in different plants facing extreme environmental conditions like salt stress ( Borzouei et al., 2012 ; Ahanger et al., 2020 ), stress imposed by heavy metals ( Singh et al., 2017 ), and allelopathic stress as well ( Al-Hawas and Azooz, 2018 ; da Silva and Vieira, 2019 ). In addition, the oxidative effects of leachates were also evident from the altered protease activity reflecting in greater damage to protein structures and hence to their functioning.…”

Reduction of Weed Growth under the Influence of Extracts and Metabolites Isolated from Miconia spp.

“…Changes in branching and root hair formation, similar to the results shown here, were also reported in red rice and barnyard grass seedlings grown with extracts and constituents of Tinospora tuberculata [ 64 ] and on morning glory and sourgrass seedlings [ 65 ]. Extracts of sicklepod ( Senna occidentalis ) caused blackening in the roots, altered root branching, shoot dwarfism, and discoloration in Tabebuia seedlings [ 66 ]. Allelochemicals decrease seedling growth as a secondary response.…”