Showing 3 results for Interactions
A. Kheiri, A. Borhani, S. M. Okhovvat, H. Eshtiaghi,
Volume 7, Issue 3 (10-2003)
Abstract
In an etiological study on stunted, nursery grown maple seedlings, a species of root-lesion nematode (Pratylenchus vulnus) and two species of fusarium (Fusarium oxysporum and F. solani) were isolated from the infected roots. Interactions between the nematode and the two fungi in a complete randomized design with six treatments and four replications were carried out under greenhouse conditions. Nematodes were surface sterilized and reared on sterilized carrot discs. Then the maple seedlings at two-leaf stage were inoculated with a population density of 40 nematodes/100 gr soil in pots. The results indicated singnificant differences between the treatments. Seven months after inoculation, the treatments with nematode alone showed a high mortality rate of about 75% along with a severe increase in population up to about 11.2 and 1266 nematodes/gr of soil and roots, respectively. In treatments with nematode and each of the two-fungus species, the deleterious effects of fungi on nematodes were observed through decrease of nematode population. It was also shown that F. oxysporum was more effective than F. solani in nematode control.
E. Sadeghi, F. Raiesi, A. Hossienpur,
Volume 23, Issue 2 (9-2019)
Abstract
Abiotic stresses such as salinity and contamination individually have a negative effect on the soil enzyme activities, whereas addition of organic matter to soil can alleviate the negative impacts of stresses on the enzyme activity. However, the combined effects of these stresses (multiple stresses) on soil biochemical conditions and the role of organic matter addition in these interactions are largely unknown. The objective of this research was to explore the interaction effect of NaCl salinity and cadmium (Cd)-pollution on the activities of catalase, alkaline phosphatase, arylsulfatase and fluorescein diacetate hydrolysis in a Cd-contaminated calcareous soil treated with alfalfa residue over 3 months of incubation. A factorial experiment with 2 levels of Cd, 3 levels of salinity and 2 plant residue treatments was conducted using a completely randomized design with 4 replications. The results indicated that salinity increased the Cd availability in both uncontaminated and contaminated soils and reduced the soil enzymatic activity. Nevertheless, addition of alfalfa residue reduced the detrimental effects of salinity and Cd-pollution on the soil enzyme activities. This indicated that in saline Cd-contaminated soils with low organic matter, adding plant residues could lower the concentration of available Cd and the effect of soil salinity with a concomitant increase of enzyme activities. So, this study showed that the joint effect of NaCl salt and Cd on enzyme activity was mostly synergistic in plant residue-untreated soils, but it was antagonistic in the plant residue-treated soils.
E. Mokallaf Sarband, S. Alimohammadi, Sh. Araghinejad, K. Ebrahimi,
Volume 24, Issue 4 (2-2021)
Abstract
In determining the allocation of water resources, the probable conditions of water resources and water demands are considered as the water allocation scenarios in the basin scale. Then, these scenarios are evaluated in the context of integrated water resources management and from the perspective of sustainable development indicators. The best scenario is selected in order to determine the water allocations. In these evaluations, there are spatial distributions and their interactions are simultaneously the key charaterictics in the decision matrix. These features are not often considered in the evaluation process. In the present study, distributed indicators and simple and integrated multi-criteria evaluation models, including ANP and CP methods, were used to evaluate the water allocation scenarios in the Aras Basin. The results showed that modeling of the spatial distribution and interactions of water allocation impacts was not possible through any of the simple multi-criteria evaluation methods. Simplifying and discarding one or two key features in the evaluation process can lead to significant uncertainties on rankings with a Spearman coefficient of -0.1. By implementing the integrated spatial decision-making approach and applying two features simultaneously, the fourth scenario was ranked first. The proposed approach was compared with the individual models, showing more accurate, with the correlation coefficients of 0.5, 0.6 and 0.7.
