植物叶片光谱角对土壤铀污染的指示作用

通过在土壤中添加浓度为0(对照组),25,75,125,175,275,375和485μg·g-1的铀,进行5种植物(苎麻、印度芥菜、酸模、甘蓝型油菜、玉米)的盆栽实验,研究了不同生长期的叶片光谱角对土壤铀污染的定性和定量指示作用,分析了定量指示作用与叶片铀含量的关系,并筛选出来在苗期即能反演土壤铀含量的植物,为通过野...

Spectral Angles of Plant Leaves as Indicators of Uranium Pollution in Soil

In this paper, five plants (ramie, Indian mustard, Rumex, Brassica napus and maize) were pot cultured with 0 (control group), 25, 75, 125, 175, 275, 375 and 485 μg·g-1 uranium in the soil. The qualitative and quantitative indicating effects of leaf spectral angle on soil uranium pollution in different growth stages were studied, and the relationship between quantitative indicating effect and leaf uranium content was analyzed It provides an effective way to quickly and safely carry out the background investigation and dynamic monitoring of soil uranium content through field measurement of plant leaf spectrum. The results and main conclusions are as follows: (1) Based on the leaf reflectance spectra of experimental plants in different growth stages, the spectral angles of soil polluted by uranium in five bands (350～716 nm for leaf pigment, 717～975 nm for red edge and near infrared platform, 976～1 265, 1 266～1 770 and 1 771～2 500 nm for water) were calculated. In most cases, the spectral angles of the five experimental plants were greater than the thresholds of the control group. The spectral angles of leaves havecomprehensive responses of 350～2 500 nm to theuranium in soil, which can qualitatively indicate whether the soil is polluted by uranium or not. (2) Eight linear regression equationspassing the significance test with spectral angles as independent variables were obtained, covering all five experimental plants. The coefficient of determination R2 of 7 linear regression equations were ＞0.64, and R2 of 3 linear regression equations (ramie-seedling stage, Indian mustard-flowering stage and rape-bud bolting stage) were＞0.81. Combined with other inversion effect evaluation indexes, it can be considered that leaf spectral angles can quantitatively indicate the degree of soil uranium pollution, but the function of the quantitative indicator varies with plant species and growth period. (3) There was a positive correlation between leaf spectral angles and uranium contents in soil. (4) The leaf spectral angles of ramie and Indian mustard at the seedling stage can be used to retrieve soil uranium content, which is an outstanding characteristic for indicating soil pollution status as early as possible through plant spectrum.