جستجوی مقالات مرتبط با کلیدواژه « سمیت » در نشریات گروه « باغبانی »

Titanium dioxide nanoparticles (TiO2 NPs) are being used widely for different purposes such as plant science and environmental remediation. Soil remediation using TiO2 NPs with the aim of minimizing their toxicity in plants requires sufficient knowledge about the fate of these nanoparticles in the soil. Excessive amounts of nanomaterials may pose inhibitory effects on the growth of plants cultivated in TiO2 NPs-affected soils. The main aim of this study was to investigate the effect of different levels of TiO2 NPs in soil on sorghum (Sorghum bicolor) growth and the fate of these nanoparticles in plants. Sorghum seeds were sown in plastic pots containing different concentrations of TiO2 NPs. Sorghum was found to be a tolerant plant species in the presence of TiO2 NPs in soil; however, addition of higher doses of TiO2 NPs (i.e., 800 and 1000 mg kg-1 soil) adversely affected seed germination and plant growth. Results indicated that the total titanium (Ti) contents in sorghum treated with nanoparticles increased compared to the control. Significantly higher accumulation of Ti in the root compared to the shoot of sorghum was observed in all of the treatments. Results indicated that the total Ti contents in the plants treated with TiO2 NPs were higher than those in control, with the highest Ti accumulation capacity of 21.32 mg per pot obtained in the soil treated with 500 mg kg-1 TiO2 NPs. Toxicity of higher doses of TiO2 NPs to the plants was observed in this study. The results showed that sorghum has an acceptable tolerance in the low to moderate concentrations of TiO2 NPs, whereas the high concentrations of these nanoparticles have inhibitory effects on the sorghum growth. Selection and application of proper doses of nanomaterials may prevent their negative effects on affected plants, while promoting the plant phytoextraction ability.

To investigate the effects of mycorrhizal fungi on growth characteristics, physiology, and essential oil yield of thyme (Thymus vulgaris L.) under lead (Pb) stress, a factorial experiment was conducted in a completely randomized design with three replications in the research greenhouse of University of Mohaghegh Ardabili (UMA) in 2018. Experimental treatments included different levels of Pb heavy metal (0, 200, and 400 ppm) and inoculation with mycorrhizal fungi (without inoculation, inoculation with Funneliformis mosseae, and Claroideoglomus etunicatum). The results showed that in comparison with the control, with increasing Pb concentration in the soil, plant height (40.56%), number of leaves (36.09%), stem dry weight (43.50%), essential oil percentage (40%), and cell membrane stability (16.14%) were significantly decreased, while proline content (51.72%) and catalase activity (45%) of the leaves increased. Inoculation of thyme with the mycorrhizal fungi was effective in increasing the vegetative indices in presence of Pb heavy metal so that both G. mosseae and G. etunicatum increased the number of leaves by 66.20 and 9.55% compared to the control, respectively. Also, inoculation with G. mosseae under severe Pb stress conditions (400 ppm) increased leaf proline content (11.49%), peroxidase enzyme activity (8.8%), chlorophyll b (21%), total chlorophyll (70.43%), carotenoids (19.6%), and essential oil percentage (55%) compared to the control. Overall, both mycorrhizal fungi were effective on alleviation of Pb toxicity effects and F. mosseae had better performance, especially in terms of morphological traits and essential oil yield. Due to the negative effects of heavy elements on human health, the recommendations to use mycorrhizal fungi to reduce the absorption of heavy metals in plants should be done with more consideration of all aspects including the plant and fungus species type and rate and pollution type.

Planting date of most annual medicinal species is associated with severe irrigation competition of winter and spring crops. This competition reduces the volume of river water in downstream and consequently the concentration of heavy metals caused by industrial and municipal wastewater is increased in the river. Therefore, in order to investigate the tolerance of some spring medicinal plants to the cadmium stress of irrigation water, a factorial experiment was performed in a completely randomized design with four replications. Treatments consisted of six medicinal plants (Portulaca oleracea L., Nigella sativa, Trigonella foenum, Anethum graveolens, Carum copticum and Ocimum basilicum) and cadmium at six levels (5, 10, 15, 20, 25 and 30 mg) plus control (no cadmium). The results showed that although low concentrations of cadmium in some plants stimulated the growth of seedlings, a concentration of 30 milligrams per liter in all plants reduced the radicle and plumule length and radicle and plumule weight as well as seed vigor index. Germination percentage and rate were not substantially affected by cadmium. In this regard, fenugreek, black cumin, and dill showed the most sensitivity to cadmium toxicity. In fenugreek and ajowan plants, the plumule length was more affected by cadmium and plumule length was determined as a sensitivity index. However, for dill, purslane, basil, and black cumin plants, the radicle length was more affected and it was determine as a sensitivity index. Overall, in terms of root length, dill and basil were identified as the most sensitive and the most tolerant species to the cadmium toxicity, respectively.

Boron toxicity is one of the most important disorders for plant cultivation in the arid and semi-arid regions. Boron accumulation usually occurs in deeper soil layers due to leaching and therefore improvement of such a soil in this situation is difficult. An experiment was conducted to find out the effect of boron on the vegetative and physiological aspects of olive trees. Six concentrations of boron (0. 2، 10، 20، 30، 40 and 50 mg/l) and two cultivars (Amygdalia and Konsevolia) were used in this experiment. The experiment was arranged in a completely randomized design with four replications. The results showed that with increasing levels of boron dry weight of leaves، stems and roots compared with controls in both cultivars declined. Amygdalia cultivar in the high concentration of boron was unable to grow and decrease in the production of new leaves was significant but Konsevolia cultivar high concentrations of boron also could grow، although the growth of this cultivar was as well significantly reduced. Efficiency of photosynthesis (Fv/Fm) in both cultivars decreased with increasing boron levels. However، Amygdalolia showed a more reduction than Konservolia. Boron toxicity symptoms appeared 45 days after the start of the experiment in concentrations (30، 40 and 50 mg/l) in Amygdalolia cultivar. However، 75 days after the Amygdaloia cultivar symptoms were observed at concentrations 40 and 50 mg/l. The results showed that olive can have a good resistance to boron toxicity، although much of this resistance is largely dependent on the cultivar.

In this study germination in vitro and in sand/compost mixture of cress (Lepidium sativum L.)، psyllium (Plantago ovata Forsk) and cumin (Cuminum cyminum L.) were evaluated. The aqueous extracts of compost strongly inhibited plant germination and root growth. The germination index values obtained for compost extracts were low، when compared with that of the control. Latent toxicity of compost for different plant species seemed not to be severe. However، when psyllium and cumin were germinated in a sand/compost mixture (25/75 and 50/50)، germination of cress was completely inhabited، with a sever reduction of the psyllium and cumin root growth. To avoid negative effects of compost on crop، routine germination bioassay should be included in education program for farmers. This showed enhance marketing and consumer acceptance of urban composts.