Evaluation of the allelopathic effect of wheat and redroot pigweed on growth indices and antioxidant system activity in intercropping
Zahra Alizadeh 1, B-D,F
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Plant, Cell and Molecular biology, Faculty of Natural Science, University of Tabriz, Iran
Animal biology, Faculty of Natural Science, University of Tabriz, Iran
A - Research concept and design; B - Collection and/or assembly of data; C - Data analysis and interpretation; D - Writing the article; E - Critical revision of the article; F - Final approval of article
Rouhollah Motafakkerazad   

Plant, Cell and Molecular biology, Faculty of Natural Science, University of Tabriz, 29 Bahman Blvd, 5166616471, Tabriz, Iran
Submission date: 2022-11-05
Acceptance date: 2023-01-09
Online publication date: 2023-01-20
  • Allelochemical compounds induced oxidative stress.
  • High density of redroot pigweed reduced the growth of wheat.
  • Activity of enzymes in wheat increased in the presence of redroot pigweed.
  • Total protein in the roots of wheat or redroot pigweed increased in intercropping.
  • GC/MS analysis showed that most of the compounds in soil extract, are allelochemical.
Allelopathy refers to the beneficial and detrimental effects of one plant on another plant in both crops and weeds through the production of secondary compounds. In order to evaluate the allopathic effects of wheat (Triticum auestivum L.) as a crop and redroot pigweed (Amaranthus retroflexus L.) as a common weed worldwide on each other in intercropping, these plants were cultivated under controlled conditions at Tabriz University laboratory. The ratios of wheat to redroot pigweed were, 100:0 and vice versa as a control, 75:25, 50:50, and 25:75. The results showed that at the ratio of 25:75 (wheat: redroot pigweed), the fresh and dry weight of roots and shoot length of wheat decreased significantly compared to the control. The fresh and dry weight of wheat shoots showed a significant decrease in different ratios versus the control. Shoot POD, root SOD, and root and shoot CAT activities in redroot pigweed increased in all intercropping ratios compared to the control. POD activity in wheat roots was higher in all ratios versus the control. Furthermore, the ratio of 75:25 (wheat: redroot pigweed) led to increased activity of POD enzymes and MDA content in wheat shoots. Moreover, roots of redroot pigweed showed increased activity of APX and SOD enzymes and MDA content. With increasing the density of redroot pigweed, soluble sugar content of wheat roots reduced significantly. However, the content of insoluble sugar and total protein increased. The root exudate compounds such as terpenoids, phenolic compounds, fatty alcohol, steroids, fatty acids, alkanes were identified using GC/MS. The findings showed that the roots were more exposed to oxidative stress due to direct contact with allelochemical compounds. Our results support the hypothesis that increasing the density can reduce the toxicity of allelochemical compounds and increasing the activity of the antioxidant system will improve plant growth under allelochemical stress.
The authors have declared that no conflict of interests exist.