锶胁迫条件下生菜光谱效应特征

Spectral Effect Characteristics of Lettuce under Strontium Stress

为了将高光谱遥感技术定量的用于植物放射性元素的胁迫程度,从水培实验采集的生化参数信息和反射率光谱信息两个方面进行研究。在室内设置了3个不同生长期、6个不同锶浓度胁迫的生菜水培试验,获取了叶片400~950 nm波段区间的生化参数(叶绿素含量、细胞结构、叶片金属含量)和反射光谱的基础信息。,利用光谱技术并结合数学统计方法研究了生菜叶片7个光谱特征参数与实测叶片锶元素含量之间的相关性,优选了较敏感光谱特征参数,建立了其与生菜叶片锶含量的线性回归模型。结果表明:锶胁迫生菜叶片叶绿素含量呈先上升后下降的规律,细胞结构差异不明显。锶胁迫生菜叶片反射光谱直观上无规律,通过采用光谱技术方法分析得出锶胁迫生菜叶片的红边波段位置先“红移”再“蓝移”,红谷波段位置则“红移”,植被指数B 4/B 3比值先升高后降低,红边归一化植被指数(normalized vegetation index,NDVI)值随着锶浓度的升高而降低。相关性及线性回归模型分析表明红边波段位置与叶片锶含量显著相关。研究成果为下一步基于光谱特征的叶片重金属含量反演模型的构建提供了较好的数据源和基础理论。

In order to quantitatively apply hyperspectral remote sensing technology to the study of plant radioelement stress,the biochemical parameter information and reflectance spectrum information collected from hydroponic experiments were studied.Three different growth periods and six different strontium concentration stress lettuce hydroponics experiments were set up in the room,and the basic information of biochemical parameters(chlorophyll content,cell structure,leaf metal content)and reflection spectrum of leaves in the 400~950 nm band were obtained.The correlation between 7 spectral characteristic parameters of lettuce leaves and measured strontium content of lettuce leaves was explored by spectral technology and mathematical statistics.The more sensitive spectral characteristic parameters were optimized,and the linear regression model between them and strontium content in lettuce leaves was established.The results show that the chlorophyll content of lettuce leaves under strontium stress increases first and then decreases,and there is no significant difference in cell structure.The reflectance spectrum of strontium stressed lettuce leaves is intuitively irregular.Through spectral analysis,it is concluded that the position of the red edge band of strontium stressed lettuce leaves first“red shift”and then“blue shift”,and the position of the red valley band is“red shift”.The ratio of vegetation index B 4/B 3 first increases and then decreases.The normalized vegetation index(NDVI)value of the red edge decreases with the increase of strontium concentration.Co-rrelation and linear regression model analysis shows that the position of red edge band is significantly related to strontium content in leaves.The research results provide a good data source and basic theory for the next step of building the retrieval model of leaf heavy metal content based on spectral characteristics.