Agriculture and horticulture
R. Rostami; B. Esmaielpour; S.A. Hosseini; G. Salimi; A. Etminan
Abstract
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 ...
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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.
A. Spanany; S. Fallah
Abstract
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 ...
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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.
