Response of arbuscular mycorrhizal mungbean plants to ambient air pollution

Abstract

ABSTRACT:The experiments were conducted in open top chamber system installed at the University of the Punjab,Quaid-e-Azam Campus, Lahore, Pakistan. The mungbean (Vigna radiata (L.) Wilczek var.M28) seeds were sown in earthen pots and were kept in filtered air, unfiltered air and ambient air. The ozone concentration was monitored daily during 1000hrs till 1600 h. The data for light intensity and relative humidity was also regularly collected. The sets of plants growing in FA chambers (without ozone and dust particles) responded well as regards growth and yields are concerned. Unfiltered air reduced the number of nodules, their biomass and nitroginase activity in mungbean plants. The present study documents that the species of mycorrhizal fungi sensitive to tropospheric ozone failed to reproduce in ambient air and unfiltered air chambers (without dust particles). Out of a total of 24 species, eighteen species belonged to the genus Glomus, two each to Sclerocystis, to Acaulospora and one each to Gigaspora and Scutellospora. The total number of species was variable during the growth phase. The total number of species reduced in soil of UFA chambers with the passage of time. Species richness reduced to almost half in UFA plants as compared to FA plants. Species of the Genus Glomus were highly abundant species at various harvests in all air treatments. Amongst most abundantly recovered Glomus species were G. fasciculatum, G. mosseae, G. aggregatum, G. caledonicum, G. deserticola, G. geosporum, and G. monosporum. The pattern of abundance kept on varying at various harvests for different air and mycorrhizal treatments. In the case of plants of UFA treatment, only two species of Glomus were abundant namely G. fasciculatum and G. geosporum. Species of Acaulospora and Gigaspora in particular and Scutellospora and Sclerocystis in general were sensitive to polluted air.

Effects of elevated O3 on microbes in the rhizosphere of mycorrhizal snap bean with different O3 sensitivity

“…2). This is possibly because reduced photosynthesis and carbon allocation to the root system inhibit mycorrhizal development (Nasim et al 2007). We studied carbon allocation by 13 CO 2 injection in this experiment and found that elevated O 3 caused 13 C abundance to decrease by 17.3% in roots of mycorrhizal S156 plants and by 25.0% in roots of mycorrhizal R123 plants relative to ambient O 3 (data not shown).…”

N-fixation in legumes – An assessment of the potential threat posed by ozone pollution

“…Tingey & Blum, 1973;Blum & Tingey, 1977), though impacts of >20% can also occur in legumes after the seasonal exposure to means >60ppb (e.g. Nasim et al 2007;Hewitt et al 2014). Several studies also report decreased N-fixation parameters, with the majority of concerned studies having focused on negative effects in clover and soybean (Table 1), although ozone-induced suppression of N-fixation rates have also been reported in peanut, chickpea, faba bean, mung bean and cowpea.…”

“…Eleven studies have considered the interactive or additive effects of ozone and other stressors or variables on N-fixation (Table 1), including interspecific competition (Kochhar et al 1980;Montes et al 1983), salinity (Welfare et al 2002), sulphur dioxide and acid rain (Reinhart and Weber, 1980;Jones et al 1985;Nazzar, 2002), nitrous oxide (Nasim et al 2007) drought (Flager et al 1987 and elevated concentrations of carbon dioxide (CO2) (Cong et al 2009;Cheng et al 2011). The effects of these additional environmental stressors are largely additive.…”

Assessing the Indoor Pollutants Effect on Ornamental Plants Leaves by FT-IR Spectroscopy

“…As a consequence, stomatal apertures are poorly regulated, chloroplast thylakoid membranes are damaged, rubisco is degraded, and photosynthesis is inhibited [42]. Ozone reacts with O 2 and produces reactive oxygen species, that denature proteins and damage nucleic acids (thereby giving rise to mutations), and also cause lipid peroxidation, which breaks down lipids in membranes [42]. Cells are protected, at least in part, from reactive oxygen species by enzymatic and nonenzymatic defense mechanisms [43].…”