水稻叶绿素浓度对荧光光谱的影响

摘要

为了加强对水稻生长状况的监测，指导水稻的田间施肥，提高施肥利用效率，以增加农作物产量、提高粮食品质，实验室搭建了基于激光诱导荧光技术的荧光探测系统，以研究水稻叶片的叶绿素含量与荧光峰值比之间的相关性。文中测量样本为水稻分蘖期和拔节期的倒二叶，栽培地区位于中国江汉平原。文中先采用凯氏定氮法和相应公式结合测得水稻叶片的叶绿素含量(mg·g-1)，再用搭建的荧光探测系统采集了水稻叶片不同叶绿素含量的荧光光谱(激发波长为355 nm)。获得了水稻叶片在不同叶绿素含量下的荧光光谱数据库，定量分析了荧光峰值比F740/F685(荧光谱峰740 nm、685 nm处的荧光强度比)与叶绿素含量的相关性，发现叶绿素含量的变化对荧光光谱特性影响明显。由实验数据分析可知荧光参数中的峰值比(F740/F685)与叶绿素含量呈现很好的线性正相关，相关系数(R2)在水稻的分蘖期和拔节期分别达到了0.9013和0.9125。实验分析结果表明诱导荧光光谱技术具有方便、快捷、无损等优点，在农作物生长状况的遥感定量监测等方面也具有一定发展潜力。%In order to enhance the monitoring of paddy growth,utilize the fertilizer more efficiently,increase crop yield and improve the quality of grain,thus the system of laser-induced fluorescence (LIF)was built.The system was designed to study the relationship between the rice leaf chlorophyll content and fluorescence ratio. In this paper,the samples came from the second upper leaves of paddy in shooting stage and the cultivated area was located in Jianghan plain of China.Firstly,the Kjeldahl method combined with the formula which was de-scribed by Zivcak et al.was utilized to calculate the chlorophyll content of paddy,then the fluorescence spec-trum of paddy leaf with different chlorophyll content by the instrument of laser-induced fluorescence (the wavelength of excitation 355 nm).Fluorescence spectra of paddy leaf with different chlorophyll content were collected and then a fluorescence spectra database was established.It is discussed that the relationship between the ratio of fluorescence (F740/F685 is the ratio of fluorescence intensity of 740 nm dividing that by 685 nm)and the chlorophyll content of paddy.It is found that the effect of chlorophyll content on the fluorescence spectral characteristics is evident.The results demonstrated that it has the tightly positive correlation between the fluo-rescence ratio (F740/F685 )and chlorophyll content of paddy leaf.The determination coefficient (R2 )can reach up to 0.901 3 and 0.912 5 at tillering stage and shooting stage,respectively.The experimental analysis showed that the LIF technology has the advantages of convenient,quick and nondestructive,and it has the po-tential for quantitative monitoring of crop growth.