米镉积累时期解析及生物菌肥与石灰配施对其积累的影响研究

发布时间：2018-03-24 01:19

本文选题：Cd　切入点：水稻生长　出处：《湖南农业大学》2015年硕士论文

【摘要】：为了解析水稻米镉的积累时期,寻找适合的阻控Cd的改良剂,本文通过不同浓度的Cd胁迫对水稻种子萌发的试验及对幼苗培育试验,分析Cd胁迫对种子及幼苗的影响,选择合适的Cd浓度进行全生育期营养液培养试验,再通过不同生育期后添加外源Cd及不同生育期后不添加外源Cd两种试验,利用理论“减法”,相互验证,得到不同生育期对水稻中米镉积累的贡献率,并开展了生物菌肥与石灰配施对水稻米镉积累的影响研究,为开展米镉控制工作提供理论依据及实用技术参考,主要试验结果如下：(1)通过水稻种子萌发试验及幼苗培育实验,使水稻种子在萌芽中及幼苗阶段接受不同浓度的Cd胁迫,研究Cd对种子萌芽及幼苗生长的影响,结果表明：5 mg·L~(-1)的外源Cd浓度为抑制种子萌发的临界浓度。水稻种子萌发环节可承受的Cd胁迫浓度范围0-5 mg·L~(-1)。且1mg·L~(-1)的Cd浓度为显著影响水稻幼苗根长、苗高及生物量(干重)临界浓度,幼苗正常生长情况下积累的Cd随着Cd浓度的增加,其中Cd浓度为0.05 mg·L~(-1)能较真实的反映出水稻正常积累、吸收Cd的情况。(2)通过水稻(玉针香)不同生育期后添加50μg·L~(-1)外源Cd对水稻生长及吸收积累Cd的影响,结果表明：水稻各部位Cd浓度随着接受Cd胁迫的时间长短而变化,与接受Cd胁迫的时间具有显著的正相关；且各部位对Cd的吸收积累表现出一致的梯度变化,稻杆部分：根部茎鞘叶片；稻穗部分：谷壳糙米；谷壳中的Cd 56.27%来自分蘖拔节期,18.69%来自抽穗扬花期,而糙米中Cd 35.11%来自分蘖拔节期,26.61%来自灌浆乳熟期。(3)通过(湘晚籼13号)不同生育期后水稻不添加对水稻生长及吸收积累Cd的影响,结果表明：外源Cd浓度控制为50μg·L~(-1),不会显著影响水稻的正常生长：植株内积累的Cd浓度随着接受Cd胁迫的时间长短而变化,具有一定的线性关系；各部位积累的Cd含量表现为：根部茎鞘叶片谷壳糙米；谷壳中Cd43.64%来自成熟期,24.06%来自分蘖期积累,14.21%来自抽穗期,而糙米中Cd 36.36%来自分蘖期,18.18%来自灌浆期,16.36%成熟期。(4)采用田间随机区组实验的方法,研究了基施生物菌肥(Bi)与追施石灰处理(L)及其配合施用(L+Bi)对水稻(湘晚籼12号)生物量、水稻对土壤Cd的富集情况、4个生育期内器官间转运系数以及各部位中Cd的含量的影响。结果表明,与CK相比,试验处理组都对水稻体的生物量无明显影响,而且对水稻各部位的Cd含量有显著的阻控作用,能够有效的降低水稻各部位对土壤中Cd的富集,显著降低了水稻谷壳中Cd的含量。其中生物菌肥与石灰配施(L+Bi)的处理糙米中Cd含量降低率为84.76%,效果最佳。
[Abstract]:In order to analyze the accumulation period of cadmium in rice and to find a suitable modifier for inhibiting CD, the effects of CD stress on seed germination and seedling cultivation of rice were analyzed by CD stress of different concentrations. The suitable concentration of CD was selected for the whole growth period nutrient liquid culture experiment, and then through the experiment of adding exogenous CD after different growth period and not adding exogenous CD after different growth period, the theory "subtraction" was used to verify each other. The contribution rate of cadmium accumulation in rice at different growth stages was obtained, and the effects of combined application of biological bacterial fertilizer and lime on cadmium accumulation in rice were studied, which provided theoretical basis and practical technical reference for rice cadmium control. The main results were as follows: (1) through rice seed germination test and seedling cultivation experiment, rice seeds were subjected to different concentrations of CD stress during germination and seedling stage, and the effects of CD on seed germination and seedling growth were studied. The results showed that the exogenous CD concentration of 5 mg / L (1) was the critical concentration to inhibit the seed germination. The CD concentration of rice seed germination was 0-5 mg / L ~ (-1) and the CD concentration of 1mg / L ~ (-1) significantly affected the root length of rice seedlings. The critical concentration of seedling height and biomass (dry weight), CD accumulation under normal growth condition, and CD concentration of 0.05 mg / L ~ (-1) could truly reflect the normal accumulation of rice. The effect of exogenous CD on the growth and uptake of CD in rice was studied. The results showed that CD concentration in different parts of rice changed with the duration of CD stress. There was a significant positive correlation between CD stress and CD uptake and accumulation, and there was a consistent gradient change in CD uptake and accumulation in different parts of rice, including root, stem and sheath leaves, rice panicle, husk brown rice. 56.27% of CD in husk came from tiller jointing stage and 18.69% from heading and flowering stage. However, 35.11% of CD in brown rice came from tiller and jointing stage and 26.61% from milk-filling stage. The results showed that the control of exogenous CD concentration at 50 渭 g / L could not significantly affect the normal growth of rice. There was a linear relationship between the CD concentration accumulated in the plant and the duration of CD stress. The CD content in the roots, stem and sheath leaves of brown rice, CD 43.64% in the husk came from the mature stage and 24.06% from the tillering stage, and 14.21% from the heading stage. While 36.36% of CD in brown rice came from tillering stage, 18.18% from grain filling stage, and 16.36% from maturing stage. Using the method of random block experiment in the field, the biomass of rice (Xiangduan indica 12) was studied by basal application of biological microbial fertilizer (Bi) and lime treatment (LL) and its combined application. The effects of rice on CD enrichment in soil, translocation coefficient between organs and CD content in different parts of rice during four growth periods were studied. The results showed that compared with CK, the biomass of rice body was not significantly affected by the treatment group. Moreover, CD content in different parts of rice could be significantly inhibited and controlled, which could effectively reduce the accumulation of CD in soil in different parts of rice. CD content in rice husk was significantly decreased, among which the CD content in brown rice treated with bio-microbial fertilizer and lime combined with LBi) was 84.76, and the effect was the best.
【学位授予单位】：湖南农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S511;X56

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