干旱和盐碱胁迫下玉米幼苗叶片光电信号的采集与分析

发布时间：2019-06-03 10:27

【摘要】：干旱和盐碱胁迫是植物在自然环境中遭遇的最常见的渗透胁迫,研究植物对这两种渗透胁迫的应答机制对植物抗逆性研究具有重要意义。植物细胞在生命活动中会产生自发光子辐射和延迟光子辐射,这些发光信号是细胞生命活动的重要信息,研究和解读植物发光信号的规律和意义有可能为评价干旱和盐碱胁迫下细胞生命状态及其系统内部功能变化提供一种无损、高效的光学活检新技术。在生命活动中,植物内部还存在电位波动,对植物电位波动信号的解读也可能为干旱和盐碱胁迫下植物细胞功能状态及其代谢调节提供一种可以实时、在位和无损伤检测的新方法。为了研究和解读干旱和盐碱胁迫下植物叶片光电信号,本文采用渗透势为-O.1MPa的PEG-6000溶液、浓度为lOOmmol/L的NaCl溶液和pH值为9.09的混合盐碱溶液分别对玉米幼苗进行干旱、单盐和盐碱胁迫,分析了该胁迫环境下的玉米幼苗叶片的自发光子辐射、延迟光子辐射和叶片表面电位波动信号的特征及其变化规律,同时测量和分析了玉米叶片生理生化指标的变化。结果发现,干旱、NaCl胁迫和盐碱胁迫都会造成玉米叶片自发光子辐射的减小,延迟光子辐射中的动力学参数初始光子数I0、衰减参数β、相干时间τ和延迟光子辐射积分强度I(T)均出现了下降的趋势,表明叶片的光合作用能力和呼吸代谢受到了抑制,细胞内各功能分子之间的相互作用减弱。结果还表明,玉米叶片表面电位波动在频谱上具有确定的规律性,其可以通过边际谱特征参数边缘频率SEF、重心频率SCF和边际谱熵MSE定量表征;在干旱和盐碱胁迫过程中,玉米叶片的SEF、SCF和MSE均出现了持续波动的变化特征,干旱和盐碱胁迫使玉米叶片电信号的边际谱向低频段移动,表明叶片细胞群电生理活动受到了抑制,不同品种的玉米幼苗所受到的盐碱胁迫的抑制程度不尽相同。为了阐明干旱和盐碱胁迫下玉米幼苗叶片光电信号变化的生物学意义,本文还研究了干旱处理下玉米幼苗叶片鲜质量、叶绿素含量以及MDA含量的变化。结果发现,在干旱胁迫下,玉米幼苗叶片的质量、叶绿素含量出现下降的趋势,MDA含量则大幅度增加,表明干旱胁迫影响了玉米幼苗的正常生长,使得玉米叶片中叶绿素含量降低和MDA含量的增加,后者可能是干旱胁迫下玉米叶片光子辐射降低和玉米叶片电信号向低频段移动的原因。上述研究结果为逆境下植物细胞功能状态的变化和植物抗逆性的定量、无损和实时在位检测奠定了基础。近年来,极低频脉冲电场(ELF-PEF)生物学效应引起重视,其有可能为物理农业提供一种新技术。为此,作为研究的拓展,本文还研究了 ELF-PEF对玉米幼苗抗旱性的影响,及基于植物发光信号定量和快速评价ELF-PEF对玉米幼苗抗旱性影响的可行性,研究结果为开发利用物理技术提高农业水平及植物无损检测技术提供了参考。
[Abstract]:Drought and saline-alkali stress are the most common osmotic stress encountered by plants in the natural environment, and the research on the response mechanism of the plants to the two kinds of osmotic stress is of great significance to the research of plant stress resistance. plant cells generate spontaneous photon radiation and delayed photon radiation in vital activity, which are important information for cell life activities, The study and interpretation of the law and significance of the plant luminescence signal may provide a non-destructive and efficient optical biopsy technique for evaluating the life state of the cells under drought and saline-alkali stress and the changes in the internal function of the system. In the life activity, there is a potential fluctuation in the plant, and the interpretation of the plant potential fluctuation signal may also provide a new method for real-time, in-place and non-invasive detection of the functional state and the metabolism of the plant cells under drought and saline-alkali stress. In order to study and interpret the photoelectrical signals of plant leaves under drought and saline-alkali stress, a PEG-6000 solution with an osmotic potential of-O. 1MPa, a NaCl solution with a concentration of lOOmmol/ L and a mixed saline-alkali solution with a pH of 9.09 were used to study the drought, single salt and saline-alkali stress of the corn seedlings, respectively. The spontaneous photon radiation of maize seedling leaves under the stress environment, the characteristic of delayed photon radiation and the wave signal of the surface potential of the blade were analyzed, and the change of the physiological and biochemical indexes of the maize leaves was also measured and analyzed. The results show that drought, NaCl stress and saline-alkali stress can lead to the decrease of the spontaneous photon radiation of the maize leaves, and the initial photon number I0, the attenuation parameter, the coherence time and the delayed photon radiation integral intensity I (T) of the delayed photon radiation have decreased. It is shown that the photosynthetic capacity and respiratory metabolism of the leaves are inhibited, and the interaction between the functional molecules in the cell is reduced. The results also show that the surface potential fluctuation of the corn leaves has a certain regularity in the frequency spectrum, which can be quantitatively characterized by the edge frequency SEF, the center of gravity frequency SCF and the marginal spectrum entropy MSE of the marginal spectrum characteristic parameters, and the SEF of the corn leaves during the drought and the saline-alkali stress process, Both the SCF and the MSE have the characteristics of continuous fluctuation, and the marginal spectrum of the electric signal of the maize leaves is shifted to the low-frequency section by the drought and the saline-alkali stress, indicating that the electrophysiologic activity of the leaf cells is inhibited, and the degree of inhibition of the saline-alkali stress of the maize seedlings of different varieties is different. In order to elucidate the biological significance of the photosignal changes of maize seedling leaves under drought and saline-alkali stress, the changes of fresh quality, chlorophyll content and MDA content of maize seedling leaves under drought treatment are also studied. The results showed that, under the drought stress, the quality of the leaves of the maize seedlings and the decrease of the content of the chlorophyll, the content of MDA increased greatly, indicating that the drought stress affected the normal growth of the corn seedlings, so that the content of chlorophyll and the content of MDA in the corn leaves increased, The latter may be the cause of the lower photon radiation and the movement of the maize leaf electrical signal to the low frequency section under drought stress. The results showed that the change of the functional state of the plant cells and the quantitative, non-destructive and real-time in-place detection of the plant cells in the event of adversity lay the foundation. In recent years, the biological effect of extremely low-frequency pulsed electric field (ELF-PEF) has been paid attention, and it is possible to provide a new technology for the physical agriculture. To this end, the effect of ELF-PEF on drought resistance of maize seedlings was also studied, and the effects of ELF-PEF on drought resistance of maize seedlings were also studied. The results of the study provide a reference for the development and utilization of physical technology to improve the agricultural level and the non-destructive testing technology of plants.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S513;TN911.6

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