Zhao et al. reported an growing trend (but statistically insignificant) in total chlorophyll content in cucumber (Cucumis sativus) treated with 400 and 800 mg/kg bare-ZnO NP in soil (Zhao et al., 2013b). Zinc is an vital micronutrient in plants (Hansch and Mendel, 2009) but above a “threshold” concentration, the element can produce toxicity in distinct plant species (BML-275 dihydrochloride site Broadley et al., 2007; Zhao et al., 2013b). For instance, Kupper et al. (1996) reported that zinc can substitute the central metal atom magnesium (Mg2+ ) in chlorophyll, causing a breakdown from the photosynthetic procedure. It has been reported that above 200 mg/kg (threshold value) in leaf tissues, Bacopa monniera and Lolium perenne L. cv Apollo showed phytotoxicological responses (Ali et al., 2000; Bonnet, 2000). In our study, the maximum Zn concentration in leaf was <300 mg/kg DW. This value is likely less than the threshold Zn tolerance value (not determined here) for green pea leavesFrontiers in Plant Science | http://www.frontiersin.orgJanuary 2016 | Volume 6 | ArticleMukherjee et al.Nanoparticle Doping Impacts Phytotoxicityunder our particular growth condition. Moreover, at 1000 mg/kg, carotenoid concentrations increased up to 9 fold, compared to control. Carotenoids are photo-absorbing pigments which might have protected Chl-a from photooxidation (Lichtenthaler, 1987). In leaf tissues, the unchanged (Chl-b) or increased (Chla, carotenoids) pigment content clearly suggests little or no toxicity to photosynthetic pigment production with Zn exposure. However, these findings may not exclude the possibility of damage to other components of the photosynthetic apparatus, e.g., electron transport chains and photosynthetic enzyme activities. Further biochemical investigations are warranted to evaluate the effects of ZnO NP exposure on other complex photosynthetic components.Effects of NPs on Green Pea Seed QualityExposure to Zn, regardless of type, generally had little effect on the green pea pod characteristics. The pod length, pod weight, and number of seeds per pod did not change as a function of treatment, with the exception of doped 250 mg/kg nanoparticles (data not shown). Here, the number of seeds per pod decreasedby 33 compared to that of bare ZnO NP treatment. Unlike bulk treatments, bare, fpsyg.2014.00726 doped, and coated NPs showed improve in Zn uptake at 250 mg/kg remedy, when compared with control (Figure six). At 1000 mg/kg, the Zn content material enhanced by 2?.5 times in all NP and bulk treatments as in comparison with handle. The ionic therapies did not show any significant change in Zn uptake at five mg/kg or 20 mg/kg. Concentrations of Cu, Mg, and K in the seed did not modify considerably with Zn exposure (data not shown). The Fe level was considerably elevated by the coated (250 mg/kg) and doped (1000 mg/kg) therapies. Moreover, at 1000 mg/ kg coated treatment, P and Mn had been substantially elevated (Figures 6B ). General, Zn exposure, regardless of variety or concentration, had little influence on the protein or carbohydrate profile from the green pea seeds. The amount of acid-soluble (glutelin), salt-soluble (globulin), water-soluble (albumin), and alcoholsoluble (prolamin) protein fractions remained unaltered in dar.12324 all treatment options (Figure S6). There was a decrease in glutelin quantity (50 ) at 1000 mg/kg doped treatment, in comparison with manage, but on account of substantial variability and modest replica.