Identification of phytotoxins in different plant parts of Brassica napus and their influence on mung bean

Abstract

Plants in Brassica genus have been found to possess strong allelopathic potential. They may inhibit seed germination and emergence of subsequent crops following them in a rotation system. Series of laboratory and greenhouse experiments were conducted to determine the allelopathic impacts of Brassica napus L. against mung bean. We studied (1) the effects of aqueous extract (5%) of different plant parts (root, stem, leaf, flower, and whole plant) of B. napus, (2) the effects of leaf and flower extracts of B. napus at 0, 1, 2, 3, and 4% concentrations, and (3) the effect of residues of different B. napus plant parts and decomposition periods (0, 7, 14, and 21 days) on germination and seedling growth of mung bean. Various types of phenolics including quercitin, chlorogenic acid, p-coumeric acid, m-coumaric acid, benzoic acid, caffeic acid, syringic acid, vanillic acid, ferulic acid, cinamic acid, and gallic acid were identified in plant parts of B. napus. Among aqueous extracts of various plant parts, leaf and flower were found to have stronger inhibitory effects on germination and seedling growth traits of mung bean, higher concentrations were more toxic. The decomposition period changed the phtotoxic effect of residues, more inhibitory effect was shown at 14 days decomposition while decomposition for 21 days reduced inhibitory effect. The more total water-soluble phenolic was found in 5% (w/v) aqueous extract and 5% (w/w) residues of B. napus flowers at 14 days of decomposition (89.80 and 10.47 mg L), respectively. The strong inhibitory effects of B. napus should be managed when followed in rotation.

Italian ryegrass desiccation periods on corn performance: is growth inhibition due to the release of plant allelochemicals or nitrogen immobilization?

“…Therefore, corn should be sown more than 30 days after the ryegrass desiccation since there will be no phytotoxic influence and nitrogen immobilization effects after this period. The increase in inhibitory effect on germination and seedling growth by phytotoxic extract concentration is supported by the results of Mehmood et al (2018), who observed a similar allelopathic influence of Brassica napus against mung bean germination, in this case, after 21 days the inhibitory effect was reduced, because as the decomposition period changed the phytotoxic effect of the residues. Abbas et al (2009) observed a significant inhibition of different rice germination traits of rice due to the allelochemical influence of weed species.…”

Weed suppression and antioxidant activity of Astragalus sinicus L. decomposition leachates

“…The green manure straw takes time to release the goosegrass-resistant potential substances and these substances may be produced with concomitant degradation, which gives rise to a peak in concentration, preceded by a gradual increase in goosegrass suppression potential and followed by a decrease. In a study exploring the effects of Brassica napus decomposition on the growth of mung beans, the decomposition period changed the phytotoxic effect of residues; more inhibitory effects were shown at 14 days of decomposition, whereas decomposition for 21 days reduced the inhibitory effect ( Mehmood et al., 2018 ). Puig et al.…”

Assessment of Phytotoxins Using Different Technologies

“…Despite the enormous number of phytotoxins and secondary metabolites produced in plants, these toxins' comprehensive identification and characterization have been studied in limited numbers. Mehmood et al [29] identified the different types of phenolic compounds such as quercitin, coumaric acid, ferulic acid, benzoic acid, cinnamic acid, caffeic acid, syringic acid, gallic acid, and chlorogenic acid in Brassica napus. Günthardt et al [30] conducted a comprehensive study and identified 1,586 plant phytotoxins, of which more than 60% belonged to the alkaloid and terpene classes.…”

“…In bioassay methods, depending on the plant species, the phytotoxin content of seeds, buds, leaves, roots, and even protoplasts can be targeted. However, the whole plant bioassay is also one of the most common methods [29,45].…”

“…High performance liquid chromatography (HPLC) (-)-Epicatechin Actinidia deliciosa [16] Methyl gallate Caesalpinia mimosoides [64] Salsolol and balanochalcone Ambrosia salsola [87] Indole-3-carboxaldehyde and (6R,9S)-3-oxo-a-ionol Asystasia gangetica [52] Phenols, flavnoids and tannins Capparis cartilaginea [44] Quercetin, chlorogenic acid, p-coumaric acid, m-coumaric acid, benzoic acid, caffeic acid, syringic acid, vanillic acid, ferulic acid, cinnamic acid, and gallic acid Brassica napus [29] Reverse-phase HPLC 5,7-dihydroxyphthalide and altechromone Rumex maritimus [62] Ultrahigh-pressure liquid chromatography mass spectrometry (UHPLC/MS)…”