鎘(Cd)對(duì)生態(tài)環(huán)境有嚴(yán)重的危害,水稻中精米的鎘含量超過(guò)食品安全國(guó)家標(biāo)準(zhǔn)(GB2762-2017)規(guī)定的0.2 mg/kg即為鎘大米。在中國(guó),約13萬(wàn)公頃的土地由于受到鎘污染而無(wú)法利用。硒(Se)是一種能緩解鎘毒性的重要元素。富硒食品近年來(lái)受到越來(lái)越多的關(guān)注,但富硒水稻在減輕鎘脅迫方面的研究尚不深入。本文選用富硒水稻和非富硒水稻品種,研究了不同播種時(shí)期(早播,晚播),不同鎘和硒濃度處理下,水稻的根,莖,葉和穗(穗桿,穎殼,米糠,胚乳和胚)等器官和土壤到對(duì)重金屬的吸收與積累。進(jìn)行了四項(xiàng)獨(dú)立的野外實(shí)驗(yàn)。通過(guò)實(shí)驗(yàn)得出以下結(jié)論:1.土壤中添加硒和鎘的多少與其在水稻籽粒中的含量有顯著的線性關(guān)系。大約50-70%的重金屬在被吸水稻吸收并積累,而5-20%的重金屬則殘留于土壤中。在硒濃度為0.4 mg/kg時(shí)可以顯著提高籽粒中的總硒含量,并緩解鎘的毒性。富硒水稻和非富硒水稻的穗和根對(duì)總硒積累影響表現(xiàn)更為突出。由于米糠中積累了大部分重金屬殘留,水稻的脫殼和精加工可顯著減少稻米鎘的含量。同一水稻品種,遲播比其正常播種在籽粒中積累更多的硒和鎘�？偟膩�(lái)說(shuō),本研究發(fā)現(xiàn)硒可減輕鎘的毒性,但在T₂

【文章頁(yè)數(shù)】：141 頁(yè)

【學(xué)位級(jí)別】：博士

【文章目錄】：
摘要
Abstract
Abbreviations
1.Chapter Ⅰ.Literature Review
    1.1.Cadmium
        1.1.2.Effect of Cd on human health
        1.1.3.Cd uptake and translocation in rice
        1.1.4.Heavy metal mediated response in damaging higher plants development
        1.1.5.Effect of Cd on mineral’s uptake and translocation in distinct plant parts,altering the nutritional status of crops
        1.1.6.Effect of Cd on plant health and riskless range
        1.1.7.Effect of Cd on plant’s functional response
        1.1.8.Management strategies of Cd stress
    1.2.Selenium
        1.2.1.Selenium available forms and ionic State
        1.2.2.Effect of Se on plant health
        1.2.3.Se uptake and transport in plants
        1.2.4.Effect of Se on living bodies
        1.2.5.Selenium protective role in scavenging Cd oxidative damages
        1.2.6.Research status of Selenium biofortification
        1.2.7.Research progress on the treatment of selenium applied by exogenous sources to produce selenium-rich crops
        1.2.8.Screening of selenium-rich breeding material
            1.2.8.1.Z5097A and Z5097B breeding process
            1.2.8.2.Z2057A,Z2057B,Z3055A and Z3055B breeding process
    1.3.The need for the project and significance of this study
    1.4.Research content and technical route map
2.Chapter Ⅱ Experiment1.Crosstalk between Cadmium and Selenium at Elevated Cadmium Stress Determine the Fate of Selenium uptake in Rice
    2.1.Introduction
    2.2.Material and Methods
        2.2.1.Experimental Material
        2.2.2.Planting Conditions
        2.2.3.Nutrient treatments used in the experiment
        2.2.4.Selenium content in Na₂SeO3

        2.2.5.Cadmium content in CdCl₂.2?H₂O
        2.2.6.Selenium and cadmium stress treatment groups
        2.2.7.Sample preparation and metal analysis
        2.2.8.Determination of total Se in rice samples
        2.2.9.Determination of Cd contents in rice samples
        2.2.10.Determination of Se and Cd in soil samples
        2.2.11.Estimation of heat units for each respective stage
        2.2.12.Statistical Analysis
    2.3.Results and Discussions
    2.4.Summary
3.Chapter Ⅲ Experiment2.Effect of metal treatment on nutrition and morphophysiological properties of rice
    3.1.Introduction
    3.2.Material and Methods
        3.2.1.Nutrient treatment groups for rice morphophysiological(IRGA,SPAD)aspects determination
        3.2.2.Nutrient treatment groups for rice nutritional aspects determination
        3.2.3.Elemental Analysis
        3.2.4.Chlorophyll content(mg/g)SPAD Value
        3.2.5.Photosynthetic characteristics
        3.2.6.Grain yield(g/plant)
        3.2.7.Statistical Analysis
    3.3.Results and Discussions
    3.4.Summary
4.Chapter Ⅳ Experiment3.The paradox in accumulation behaviour of Cadmium and Selenium at different planting times in rice
    4.1.Introduction
    4.2.Materials and Methods
        4.2.1.Planting Conditions
        4.2.2.Nutrients determination and fixation for the experiment
        4.2.3.Heat units estimation and elemental analysis
        4.2.4.Physiological differences in leaves
        4.2.5.Statistical Analysis
    4.3.Results and Discussion
    4.4.Summary
5.Chapter Ⅴ Experiment4.Accumulation,mobilization and transformation of selenium in rice grain provided with foliar sodium selenite
    5.1.Introduction
    5.2.Materials and Methods
        5.2.1.Experimental Material
        5.2.2.Material pre-treatment and powder preparation
        5.2.3.Determination of total Se:electrothermal plate digestion-atomic fluorescence spectrometry
        5.2.4.Determination of inorganic Se:extraction of dilute acids- atomic fluorescence spectrometry
        5.2.5.Statistical Analysis
    5.3.Results and Discussion
    5.4.Summary
6.Experimental Findings,Conclusions and Future Prospects
7.Bibliography
Acknowledgements
Authors CV



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