光谱学与光谱分析, 2017, 37 (6): 1872, 网络出版: 2017-07-10
香樟受酸胁迫影响的高光谱诊断模型
The Hyperspectral Diagnosis Model for Acid Stress of Cinnamomum camphora
摘要
高光谱作为快速、 无损诊断技术, 在植物胁迫监测中发挥了重要作用。 但是因为硫和氮的施肥作用, 植物对酸雨的响应表现出比其他胁迫更加复杂的模式。 基于高光谱技术对香樟受四个酸雨梯度(pH 56, pH 45, pH 30, pH 20)影响的叶片光谱进行了419天的监测, 以探讨不同酸雨梯度对香樟影响的时间拐点。 首先对16期原始光谱数据进行预处理, 剔除异常值; 然后基于光谱差值(对照组pH 56与其他酸雨梯度处理下的叶片光谱差)随着喷酸时间的变化, 寻找典型波段; 在此基础上构建了香樟在酸雨处理下的光谱响应模型。 主要结论如下: 反映香樟受酸雨影响的典型波段主要集中在470~520和565~700 nm, 在此基础上构建了蓝边差值指数和黄边差值指数。 低(pH 45)、 中(pH 30)浓度的酸雨对香樟生长均呈现出先促进后抑制的作用, 时间拐点分别发生在喷酸的第100天和50天左右; 高浓度酸雨(pH 20)从喷酸初期就表现出抑制香樟生长, 且随着喷酸时间的增加抑制作用增强。 研究表明, 长时间序列的高光谱信息可以指示不同强度的酸雨对植物的促进和胁迫作用, 以及由促进到胁迫的时间拐点; 该研究也为基于卫星遥感监测区域尺度植物受酸胁迫提供了借鉴, 同时为相关部门制定酸雨政策提供了科学依据。
Abstract
The hyperspectral technique plays an important role in detecting the response of plant under the acid stress. Taking Cinnamomum camphora as the subject, the hyperspectral information at leaf scale under 419 days of acid disposals was measured. Differing from other kinds of environmental stresses, the responses of plants under acid stress are more complicated due to the fertilizer effect of sulfur and nitrogen. Based on the hyperspectral monitoring on the leaf of Cinnamomum camphora under four grades of acid rains (pH 56, pH 45, pH 30, pH 20), the aim of this study is to find the turning point from promoting to inhibiting growth by acid rain. Based on the 16 terms of hyperspectral data, the pretreatments were firstly conducted and the abnormal values were removed; and then the typical spectrals were selected based on the temporal variations of leaf response (the differences of the spectral values under pH 56 minus those under pH 45, pH 30, pH 20, respectively) under acid stresses; finally the diagnostic models were constructed using the typical spectral. The results showed that the typical bands to reflect the response of Cinnamomum camphora under acid stresses were mainly within 470~520 and 565~700 nm, based on which the difference of blue edge index and the difference of yellow edge index were built. The acid rain with pH 45 and pH 30 first promoted and then inhibited the growth of Cinnamomum camphora, with the turning point at 100 days and 50 days of spraying acid rain, respectively. The acid rain with pH 20 inhibited the growth of Cinnamomum camphora at the beginning of acid treatments, and this inhibition had been strengthened with time increasing. This study showed that the long term of hyperspectral monitoring could indicate the temporal variations of the responses of Cinnamomum camphora under acid treatments. These results could provide scientific information for monitoring the plant responses under acid rain at a regional scale, which also provide scientific suggestions for the government to enact environmental protection plans.
李新会, 张秀英, 马元丹, 金佳鑫, 程敏, 张小敏, 江洪. 香樟受酸胁迫影响的高光谱诊断模型[J]. 光谱学与光谱分析, 2017, 37(6): 1872. LI Xin-hui, ZHANG Xiu-ying, MA Yuan-dan, JIN Jia-xin, CHENG Min, ZHANG Xiao-min, JIANG Hong. The Hyperspectral Diagnosis Model for Acid Stress of Cinnamomum camphora[J]. Spectroscopy and Spectral Analysis, 2017, 37(6): 1872.