| The issue of food safety has become a modern agricultural production and sustainable development the primary factor, the edible safety of the crop has been one of the hot research. With the increasing awareness of environmental protection, the polluted environment should be improved, the study on environmental bioremediation has been the key to improve the ecological environment. With the improvement of people’s living standards, ordinary vegetables has been unable to meet the demand for vegetables, special vegetables has become the research focus. Therefore, with the development of special vegetables in Central China, aquatic vegetable watercress with its rich nutrition, wide adaptability, simple planting and extensive development and cultivation, but because of heavy metal accumulation in aquatic vegetables and other reasons, watercress safety problems have been plaguing people. How to scientific and reasonable planting watercress, make people eat to safety, nutrition specialty vegetables is an urgent problem. In this experiment, watercress (Nasturtium officinale R.Br) as material, the content of Watercress atomic fluorescence spectrometry measurement of heavy metals of Pb, Hg and Se of the nutrient elements, effects of different concentration, temperature, pH value, cultivation mode and different cultivars under Watercress enrichment capacity of heavy metal Pb, Hg and Se of the nutrient elements.1. The biggest actor affecting the watercress enrichment of Pb is difference in mixed concentration; the biggest factor affecting the watercress enrichment Hg is the temperature difference, the minimum impact way varieties and cultivation; the biggest factor affecting the watercress enrichment of Se is the difference culture method, the minimum impact temperature. Add watercress in different parts of thecontent of different elements from big to small order:add Pb solution:root> stem> leaf> leaf> old old stems; adding Hg solution:root> leaf> stem> old old new stem> leaf; adding Se solution:root> stem> leaf> new old stem> leaf.2. Different concentration (including single concentration and mixing concentration), have the effect of rich Pb ability of watercress in different parts of. With the increase of Pb concentration, watercress stem number, root mean long, edible part weight, total weight is not significant difference in P≤0.05level, plant height, edible part in P≤0.05level difference. With the increase of Pb concentration, when the concentration of added single watercress content of Pb is gradually increased, significant differences in P≤0.05level, but in a single dosage is0.2mg/L,0.3mg/L, watercress increase the content of Pb in the range of P≤0.05have no significant differences. In the single addition of high concentrations of Pb, watercress enrichment of Pb has tended to saturation, continue to smaller effect of Pb solution on the watercress content of Pb. Accumulation of Hg in different parts of the watercress in P≤0.05levels have significant differences, the specific performance of new stems, old leaves were not significantly different, but the differences are more significant and other parts, especially the old stems and roots, the most significant difference in P≤0.05level.3. Have the effects of rich Hg of different concentration, temperature, water pH value, cultivation methods, varieties and different parts. With the increase of Hg concentration, watercress stem number, plant height, edible part of no significant differences in P≤0.05level, root mean length, weight, total weight of the edible part of significant differences in P≤0.05level; with the increase of Hg concentration, the addition of single concentration of Hg content in watercress gradually increase, significant differences in P≤0.05level, but in a single dosage is O.OOlmg/L,0.005mg/L,0.0150.010mg/L, mg/L, Hg content of watercress increases no significant difference in the range of P≤0.05level;15℃in watercress enrichment of Hg is obviously much higher than20℃, significant differences in P≤0.05level,15℃cash set volume increased gradually, while in the20℃is relatively stable, no significant difference in Hg rich in P≤0.05level, or even a slightly decreasing trend; pH=6content of Watercress enriched in Hg than pH=7high many, significant differences in the P≤0.05level, pH=6accumulation increased gradually, and in the pH=7is relatively stable, no significant difference in Hg rich in P≤0.05level; water content watercress enrichment of Hg relative than soil culture should be high, in P≤0.05level difference is not significant With different addition, hydroponics containing Hg concentration is relatively stable, while in the soil, rich Hg content had significant differences in P≤0.05level. But overall, Hg rich ability difference of watercress hydroponics and soil culture was not significant; different varieties of watercress concentration of Hg had little difference, the difference was not significant in P≤0.05level; accumulation of Hg in different parts of the watercress in P≤0.05levels have significant difference, specific performance for the new stem the old leaves, the difference was not significant, but the difference with other parts are more significant, especially the old stems and roots, the most significant difference in P≤0.05level.4. Have the effects of rich Se of different concentration, temperature, water pH value, cultivation methods, varieties and different parts. With the increase of Se concentration, number of roots, the edible part weight, weight is greatly reduced, and the length, root mean long, edible part of little change in overall length, compared with the control group, Se solution was added in watercress representation than the control is better, and as the concentration increased, accumulation of Se watercress increases; when the temperature rises, medium concentration of Se addition amount of watercress Se rich ability is stronger, when the added concentration continued to increase, the better low temperature watercress Se rich ability ratio temperature; pH value increased from6to7of the watercress Se rich capacity decreased, and the difference was significant, but pH6watercress growing as pH7; cultivation of different enrichment ability of watercress the greatest impact, in addition with the same concentration of Se solution, soil culture of watercress selenium content is very small, almost negligible, but the hydroponic watercress to different concentrations of Se were added liquid reaction significantly. |
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