| In order to investigate the absorption and enrichment characteristics of Pb by ginger and its mitigation techniques,the growth,yield and quality formation and Pb uptake of ginger at different Pb levels were studied.Three soil amendments such as exogenous silicon,selenium and microbial fertilizer were analyzed.The effect of Pb enrichment on ginger was investigated and its physiological effects were alleviated.The main results are as follows:1.The response of ginger to Pb level was"Low promotion and high inhibition",and the effect on growth showed obvious time and dose effects.At the seedling stage of ginger,the growth of all organs except roots was significantly higher than that of control at 250 mg kg-1 Pb level,while the growth of ginger at 1000 mg kg-1 Pb level was significantly lower.At the harvest stage,the yield per plant was 43.54% lower than that of control,and the contents of soluble sugar,soluble protein,free amino acid and gingerol were 22.92%,32.14%,38.30% and 40.00% lower than that of control,respectively.2.The addition of exogenous silicon fertilizer,selenium fertilizer and microbial fertilizer can effectively alleviate the toxic effect of Pb on ginger.The alleviation effect is silicon fertilizer>selenium fertilizer>microbial fertilizer.At 500 mg·kg-1 Pb level,compared with the control,the plant height of three treatments at the growth stage of ginger increased by 28.65%,24.53% and 14.79%,and the fresh weight of leaves increased by103.10%,99.38% and 44.27%,respectively.The yield per plant increased by 96.06%,85.81% and 41.58%,respectively.3.The absorption and enrichment of Pb in various parts of ginger plants showed that the vertical axis gradually decreased from bottom to top,and the horizontal axis decreased gradually from the middle to the sides.For example,at the level of 500 mg·kg-1 Pb,the Pb content of roots,rhizomes,stems and leaves at the time of ginger harvesting was 52.01,4.41,1.17,0.78 mg·kg-1,respectively,Mother rhizome finger,Primary rhizome finge,Secondary rhizome finger,and Tertiary rhizome finger.The order of 17.14,5.02,1.47 and 0.38 mg·kg-1 was 1.58,1.42,0.77,0.13 mg·kg-1 in the main branch leaves,Primary branch leaves,Secondary lateral branche leaves and the Tertiary collateral leaves;At the level of 500 mg·kg-1 Pb,the content of Pb in the whole plant was increased by 57.77%,48.58% and 29.20%,respectively.The content of Pb in ginger roots,rhizomes,stems and leaves was compared with that of the control.Reduced by 61.08%,58.85%,72.52% and 81.97%.4.Ginger showed strong tolerance and ability to enrich Pb under Pb stress.Under the stress of 250 mg·kg-1 Pb,the root length of ginger was greater than the control in the whole growth period,and the root tolerance index was greater than 1;When the Pb stress level was 500 mg·kg-1 the root length of ginger decreased significantly compared with the control,and the root tolerance index decreased.The root activity of ginger treated with silicon,selenium and microbial fertilizer increased by 127.79% and 102.08%,respectively.82.64%.5.Adding exogenous silicon fertilizer,selenium fertilizer and microbial fertilizer could enhance the activity of antioxidant system and improve photosynthetic performance of ginger leaves.After adding silicon,selenium and microbial fertilizer at 500 mg·kg-1 Pb level,the chlorophyll content of ginger leaves increased by 25.97%,23.22% and 15.44%,and Pn increased by 44.68%,37.12% and 24.11%,respectively.The photochemical activity of chlorophyll Fv/Fm is also improved. |
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