عنوان مقاله [English]
Introduction: Barley is known to be an allelopathic plant and its allelopathic potential on weeds, and some other crops has been proven. Increasing use of herbicides has an adverse environmental impact and increases the weed resistance to herbicides. Eco-friendly methods for controlling weeds reduce the amount of herbicide use and reduce the damage caused by it. Some plants have alternate properties (allelopathies) that can be used to reduce or stop the growth of other plants, especially weeds. Allelopathy is an interference mechanism based on any direct or indirect effect (primarily inhibitory) by one plant on another through the release of chemicals that escape into the environment. Barley (Hordeum vulgare L. ssp. vulgare) is well known for its allelopathic compounds. The decomposition of barley plant residues in the soil, release numerous allelochemical compounds such as phenolic compounds, flavonoids, synoglycosides, alkaloids and polyamines. Till now 44 chemicals have been identified as potential allelochemicals that contribute to its allelopathic activity in Hordeum vulgare. The present work aimed to study the allelopathy potentials expressed by residues as straw among two barley genotypes on rhizome growth and physiological attribute of bindweed (Convolvulus arvensis L.).
Materials and Methods: This experiment was conducted in 2013 at Islamic Azad University, Shoushtar Branch. The experiment was factorial based on completely randomized design (CRD) with four replications. Four different amounts (10, 20, 30 and 40 g per one kg soil) of two barley cultivars (local ecotype and Sarasary 10) residual were prepared. Rhizomes were harvested from a depth of 30 cm soil and cultivated in the pot. The culture medium included plastic pots of 30 cm in diameter. The traits included seedling weight and length, malondialdehyde concentration, fatty acid percent, α-amylase activity, catalase activity, peroxidase activity, glutathione reductase activity, GA and ABA concentration of bindweed rhizome. The concentration of GA and ABA hormones was investigated based on the Kamal method. Statistical analysis was made using the SPSS Ver.13 statistical program. Significantly different means were separated at the 0.05 probability level (p = 0.05) by the least significant difference (LSD) test. Pearson’s correlation analysis was also conducted among different variables.
Results and Discussion: Results indicated the effect of genotype, residual amount and their interaction on rhizome malondialdehyde concentration, fatty acid percent, α-amylase activity, catalase activity, peroxidase activity, Glutathione reductase activity, GA and ABA concentration. Increasing the amount of residues for the local genotype caused a significant decrease in seedling fresh weight. The lowest fresh weight of bindweed was 40 g residues of local genotypes, in which was 73.6% lower than the control without residues. Increasing the amount of local and Sarasary 10 residues in the soil caused a significant reduction in the length of the bindweed seedlings. The negative effect of local ecotype residual on α-amylase activity was more than modern genotype. The mixing of 40 g residues of local ecotype and Sarasary10 genotype with soil decreased this enzyme by 38% and 79.5%, respectively, compared to the control without residues. Increasing the amount of residuals, reduces gibberellin hormone and increased rhizome the ABA content. The slope of the changes in gibberellin hormone and the increase of ABA in the local ecotype was higher than the modern genotype. Antioxidant enzymes increased in response to an increase in the amount of residues up to about 20 grams in the pot and then decreased significantly. Reducing antioxidant enzymes at high levels of barley residues led to an increase in the amount of fatty acids and Malondialdehyde, indicating the peroxidation of the cell membrane. In general, the residuals of local genotype compared to cultivar Sarasary 10 had a more harmful effect on all studied traits of bindweed rhizome and seedling. It seems that in areas where bindweed is dominant, it is possible to use local barley residuals to reduce the damages.