铯对菠菜和杨树光合作用及逆境生理指标影响的研究

发布时间：2018-02-09 21:37

本文关键词： 铯菠菜杨树逆境生理光合作用　出处：《西南科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：研究草本及木本模式植物对Cs胁迫的响应机理,可以为Cs污染的植物修复技术提供重要的理论依据和技术支持。本试验以菠菜、新疆杨为材料,分别用不同浓度的Cs Cl处理植物幼苗。其中菠菜采用石英砂培和Hoagland营养液进行培养处理,处理浓度分别为0、84、168、926、1683、3367 mg/kg;新疆杨采用土培方式培养,处理浓度分别为0、20、50、100、200、400 mg/kg。当菠菜处理3 d、6 d、9 d、12 d和15 d,新疆杨处理30 d、60 d和90 d后,分析测定Cs在两种植物体内的积累分布以及Cs胁迫对两种植物生长发育、逆境生理指标和光合作用的影响,结果表明:(1)随Cs处理浓度的增加,两种植物地上部分和地下部分Cs含量也随之升高,且菠菜地下部分Cs含量高于地上部分,转运系数在高浓度处理时有所下降;新疆杨体内各器官Cs含量分布为:茎部叶部根部,转运系数维持在较高水平。(2)低浓度Cs处理促进两种植株的生长和生物量的积累,高浓度Cs处理导致植株矮化,叶片黄枯,生物量减少,显著抑制植物生长。且菠菜处理浓度为926 mg/kg、新疆杨浓度为100 mg/kg时对植株生长的促进作用最显著。(3)Cs胁迫对两种植物抗逆生理影响的结果分析显示,随处理浓度的增加,菠菜CAT、POD、SOD酶活性呈现先升高后下降的趋势,而新疆杨在400mg/kg处理下三种酶活性仍保持在较高水平;由于Cs胁迫对膜有严重的伤害作用,膜脂过氧化引起植物的叶片受损,导致两种植物体内MDA含量增加;Pro含量随处理浓度的升高而逐渐升高,且与处理时间成正比;当Cs浓度达到50-400 mg/kg,Cs胁迫对新疆杨叶片已经造成了盐害,导致新疆杨叶片水势降低,使植物呈现缺水状态。(4)Cs胁迫对植物光合作用影响结果显示,Cs对植物叶绿素含量的影响主要为低浓度促进高浓度抑制;当菠菜处理浓度大于1683 mg/kg,新疆杨处理浓度大于200 mg/kg时,两种植物叶片净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)以及蒸腾速率(Tr)呈明显下降趋势;叶片叶绿素荧光参数分析表明,高浓度处理下,两种植物光系统II(PSII)反应中心遭到破坏。(5)高浓度Cs处理显著抑制PSII放氧侧的电子传递活性,同时类囊体膜室温吸收光谱和77K低温荧光光谱分析表明,高浓度Cs会破坏两种植物类囊体膜的结构,导致叶绿素的结合状态受损,从而使类囊体膜光能的吸收、传递和分配受到抑制,并且导致类囊体膜上PSII和PSI的色素蛋白发生不同程度的降解。
[Abstract]:The research on the response mechanism of herbaceous and woody model plants to Cs stress can provide important theoretical basis and technical support for the phytoremediation technique of Cs pollution. The plant seedlings were treated with different concentrations of Cs Cl. Spinach was cultured in quartz sand culture and Hoagland nutrient solution at the concentration of 0 ~ 844 ~ 168N ~ (926) ~ 1683N ~ (3 667) mg / kg, while Chinese poplar was cultured by soil culture. The treatment concentration was 0 ~ (20) ~ (50) C ~ (50) ~ (100) ~ (200) mg / kg 路kg ~ (-1). After treatment of spinach for 3 days, 6 days for 9 days, 9 days for 12 days and 90 days for 30 days, the accumulation and distribution of Cs in the two plants and the growth and development of the two plants under Cs stress were analyzed. The results showed that the contents of Cs in the aboveground and underground parts of the two plants increased with the increase of Cs concentration, and the content of Cs in the underground part of spinach was higher than that in the aboveground part. The content of Cs in the organs of Populus tomentosa was distributed as follows: the roots of stem and leaves, and the transport coefficient maintained at a high level. The low concentration of Cs promoted the growth and biomass accumulation of the two plants. High concentration of Cs resulted in plant dwarfing, leaf yellow and withered leaves, and decreased biomass. The effects of spinach treatment (926 mg / kg) and Chinese poplar (100 mg/kg) on plant growth were significantly inhibited. The SOD activity of spinach CAT PODN increased first and then decreased, while the activity of three enzymes remained at a high level under 400 mg / kg treatment, and the membrane lipid peroxidation caused damage to the leaves of plants due to the severe damage to the membrane under Cs stress. The increase of MDA content in the two plants increased gradually with the increase of the treatment concentration, and was directly proportional to the treatment time, and when the Cs concentration reached 50-400 mg / kg Cs stress, it had already caused salt damage to the leaves of Populus Sinensis, which resulted in the decrease of water potential in the leaves of Populus chinensis. The results showed that the effects of low concentration on chlorophyll content of plants were mainly low concentration and high concentration inhibition, when the concentration of spinach was more than 1683 mg / kg, and the concentration of Populus tomentosa was more than 200 mg/kg. The net photosynthetic rate (PN), stomatal conductance (GsN), intercellular CO2 concentration (CO2) and transpiration rate (Tr) of the two plants decreased significantly, and the chlorophyll fluorescence parameters of the leaves were analyzed under high concentration. High concentration of Cs significantly inhibited the electron transport activity of the oxygen releasing side of PSII. At the same time, the room temperature absorption spectra of thylakoid membrane and the low temperature fluorescence spectra at 77K showed that the electron transport activity of the oxygen side was significantly inhibited by the treatment of high concentrations of Cs. High concentration of Cs will destroy the structure of thylakoid membrane of two plants and cause the damage of chlorophyll binding state, thus inhibit the absorption, transfer and distribution of light energy of thylakoid membrane. The degradation of pigment protein of PSII and PSI on thylakoid membrane occurred in different degree.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X173;Q945

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