| Particulate of coal fired was the main source of air pollution coal mining area,the natural settlement of particulates often has a series of effects on the growth of crops around them.However,the process and mechanism of this effect were still unknown.In this paper,greenhouse simulated experiments were conducted to explore the effects of different concentrations of coal-fired atmospheric particulates and toxic effects on wheat(A-anti-58).The main conclusions are as follows:(1)There was no significant effect of particulate stress on chlorophyll a,chlorophyll b and total chlorophyll content of wheat at seedling stage.For jointing wheat,high concentration particles significantly reduced three indicators,compared with the blank group,the inhibition rates were 33.9%,55.5% and 54.3%;The effects of three indicators on grain filling during filling stage showed a trend of decreasing with the increase of particulate matter concentration.(2)The activity of SOD in wheat leaves decreases with increasing particle concentration at different growth stages,while the activity of peroxidase(POD)and catalase(CAT)increased with the increase of particle concentration.The SOD activity in the blank group was 1.4,1.9,and 1.6 times that of the high concentration experimental group in the three different growth stages,POD activity in the blank group was 81.2%,64.3%,and 51.8% in the high concentration group,and CAT activity was 1.2 times,79.7%,and 86.0%,respectively.(3)The activity of Ru Bp Case and ALD in leaves showed a trend of increasing first and then decreasing with the increase of particulate matter concentration in different growth stages,but there was no significant change in enzyme GAPDH.Ru Bc Case activity in the low,medium,and high concentrations experiment group of the seedling stage was 1.1,1.1 times and 75.0% for the blank group,the jointing period was 1.2 times,63.9% and 85.5% respectively,and the filling period was 1.3 times,76.2% and 1.1 times.The ALD activity of the three experimental groups was 1.5 times,1.3 times and 1.2 times of the blank group,and the jointing period was 1.4 times,1.2 times and 1.1 times,while the filling period was 92.9%,87.4% and 82.8%,respectively.(4)The contents of heavy metals Cu,Cd,Pb,and Zn in the seedling period,heavy metals Cu in the jointing period,and heavy metals Cr,Cu,As in the grain filling period generally showed a trend of increasing with the increase of particulate while the content of the underground part of wheat decreases with the increase of particle concentration,whice the heavy metal Cr in seedling period,Cu,Cd,Pb in jointing period and the heavy metals Cr,Cu,As,Cd and Pb in filling period,the contents of Cr,Cu,As and Cd in the leaves of wheat in the mature period increased gradually with the increase of the concentration of particulates,but had no significant effect on the content of roots.There was no obvious rule in the proportion of heavy metal Zn in different organs during the maturation of coal particles,but the results showed that the contents of heavy metal Zn in the organs of the blank group were all lower than the experimental group,and were significantly lower than the high concentration experimental group.The contents of roots,stems,leaves,seeds and glume were 76.5%,49.4%,59.5%,83.5% and 68.9%,respectively,in the high-concentration experimental group.(5)The subcellular distribution of wheat leaves at seedling period,the subcellular components with the highest distribution ratios of heavy metals Cd,Pb and Zn are cell wall,organelles and soluble fractions,the proportions were respectively 39.58% ~ 52.78%,61.54%~88.73%,82.12%~87.58%.The highest proportion of subcellular components of Cr is the cell wall in the jointing period,while the subcellular components with the highest proportion of Cu,As,Pb and Zn were all soluble components.the proportions were respectively 48.75% ~ 56.88%,45.66%~ 58.27%,80.00% ~ 91.67%,41.89% ~ 68.18%,44.53% ~ 59.10%.(6)Observed under scanning electron microscope,and we found that as the concentration of particulate matter increases,the surface cleanliness of the blade decreases,and the adhesion of particles was gradually serious,reduce the number of leaf hairs and cause serious structural damage,make the shape of the pore gradually flattened and the surrounding waxy structure is significantly damaged.That particles have obvious influence on the structure of wheat leaf surface morphology,and with the increase of the concentration of particles,the damage of the surface structure increases.Observed under transmission electron microscope and we found that with the increase of the concentration of particles,the cells in the leaves of wheat showed obvious plasmolysis,the structure of the chloroplast also has obvious deformation,and the blank group cell wall and cell membrane without black deposits.As the concentration of particles increases,sediments increase gradually,and large agglomerates with a diameter of about 500 nm appear in the middle and high concentrations.It indicated that particulate matter was toxic to wheat leaf cells and increased with the increase of particulate concentration. |
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