镉胁迫水稻生理功能变化遥感分析

发布时间：2018-03-09 19:49

本文选题：镉胁迫　切入点：FAPAR　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：农作物受重金属胁迫后,其生理生化参数会发生变化,并引作物能量吸收、释放和辐射的改变。针对重金属胁迫的隐蔽性和稳定性,以往监测方法主要从光谱信息增强的角度提取作物外观和叶片结构变化特征,或从时间序列分析的角度分析生物量的变化规律,但很少从能量平衡的角度分析重金属胁迫对水稻生理功能的影响。本文针对镉胁迫的累积性、隐蔽性和稳定性,结合水稻成熟期镉胁迫下作物生理功能与生理要素相互作用的生理参数,识别不同胁迫水平。本研究从重金属胁迫影响机理入手分析验证田间尺度下镉胁迫对水稻生理功能的影响。以高光谱可见光反射率和植被吸收光合有效辐射比例(Fraction of Absorbed Photosynthetically Active Radiation,FAPAR)为敏感参数从能量吸收的角度分析镉胁迫对水稻光合作用的影响,结果发现镉胁迫会抑制水稻光能吸收,导致其反射率增强且FAPAR减弱。以冠气温差为敏感参数从能量辐射的角度分析镉胁迫对水稻蒸腾作用的影响,结果发现镉胁迫会影响水稻冠层能量的释放,导致冠层辐射能量增强。为实现水稻镉胁迫大面积监测,本研究基于Landsat-8遥感影像数据、实测数据和环境数据反演水稻生理功能敏感参数。以可见光反照率和FAPAR探索和分析镉胁迫对水稻光能吸收的影响,结果发现镉胁迫会影响水稻光能吸收,且与FAPAR能很好识别轻度镉胁迫。基于能量平衡模型反演水稻蒸腾作用敏感参数和潜热通量(latent heat flux,LE),结果发现镉胁迫会抑制水稻蒸腾速率,且与LE能很好识别重度镉胁迫。水稻能量吸收、释放和辐射敏感参数只能区分两种不同胁迫水平,为提高识别胁迫精度,本文引入特征协同方法,通过协同可见光反照率、FAPAR、和LE参数的优势构建-LE特征空间和生理功能敏感指数Pf。结果显示-LE特征空间对水稻不同胁迫(轻/中/重度胁迫)的区分准确度分别为99%、88%、85%,Pf的区分准确度分别为72.84%、78.95%、90.42%。根据大面积反演结果发现重度镉污染区域主要分布在湘江附近,随着离湘江距离变大,水稻由重度镉污染渐变为轻度镉污染。
[Abstract]:After heavy metal stress, the physiological and biochemical parameters of crops will change, and the energy absorption, release and radiation of crops will be changed. In the past monitoring methods were mainly used to extract the variation characteristics of crop appearance and leaf structure from the perspective of spectral information enhancement or to analyze the variation law of biomass from the point of view of time series analysis. However, the effects of heavy metal stress on physiological function of rice were seldom analyzed from the point of view of energy balance. The physiological parameters of interaction between crop physiological function and physiological factors under cadmium stress during rice maturity were analyzed. The effects of cadmium stress on physiological function of rice under field scale were verified by analyzing the mechanism of heavy metal stress. Hyperspectral visible light reflectance and the proportion of photosynthetic effective radiation absorbed by vegetation were used to study the effects of cadmium stress on rice physiological function. Fractionation of Absorbed Photosynthetically Active radiation (FAPARA) was used as a sensitive parameter to analyze the effects of cadmium stress on photosynthesis of rice from the point of view of energy absorption. The results showed that CD stress could inhibit the absorption of light energy, increase the reflectivity and weaken the FAPAR of rice. The effect of CD stress on rice transpiration was analyzed from the perspective of energy radiation with canopy temperature difference as a sensitive parameter. The results showed that cadmium stress could affect the energy release of rice canopy and lead to the enhancement of canopy radiation energy. In order to realize the large-scale monitoring of rice cadmium stress, this study was based on Landsat-8 remote sensing image data. Using visible light albedo and FAPAR to explore and analyze the effect of cadmium stress on the light energy absorption of rice, the results showed that cadmium stress would affect the light energy absorption of rice. Based on energy balance model, rice transpiration sensitive parameters and latent heat flux latent heat fluxeles were retrieved. The results showed that cadmium stress could inhibit rice transpiration rate. The energy absorption, release and radiosensitivity parameters of rice can only be distinguished from two different stress levels. In order to improve the accuracy of stress identification, a characteristic synergistic method is introduced in this paper. Based on the synergistic visible light albedo (FAPARR), and the superiority of le parameters, we constructed the feature space of -LE and the physiological function sensitivity index Pf. the results showed that the accuracy of distinguishing between different stresses (light / medium / severe stress) of rice was as follows: -LE characteristic space. The accuracy of distinguishing PF is 72.84 and 78.95, respectively. According to the results of large area inversion, it is found that the heavily polluted areas of cadmium are mainly located near the Xiangjiang River. With the increase of distance from Xiangjiang River, rice gradually changed from heavy cadmium pollution to light cadmium pollution.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X87

【参考文献】