结合图像的叶绿素荧光动力学植物水分胁迫探测方法  

Detecting Method for Plant Water Stress with Chlorophyll Fluorescence Kinetics Based on Imaging

作　　者：周春艳[1,2] 华灯鑫[1] 乐静[1] 闫庆[1] 毛建东[2] 景敏[1] 

机构地区：[1]西安理工大学机械与精密仪器工程学院,西安710048 [2]北方民族大学电气信息工程学院,银川750021

出　　处：《农业机械学报》2017年第1期148-154,共7页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金项目(61605157;61275185;61565001);国家民委科研项目(14BFZ011)

摘　　要：为了准确、直观探测植物水分胁迫及生长状态信息,融合了叶绿素荧光动力学参数及荧光图像对不同干旱胁迫条件下的植物进行了实验观测。以460 nm蓝色LED作为激发光源,EMCCD加装690 nm带通滤光片进行荧光图像采集,对4种不同采样周期下的各1 000幅图像求每幅图的像素平均值,按时间序列绘制荧光强度,可得到信息更全面的叶绿素荧光动力学曲线,并计算得出各个动力学参数。同时,对不同时间产生的荧光图像进行降噪、乘除等运算,并用伪彩色显示,可直观分析各类因素导致的荧光分布不均匀性。对易失水叶片和非易失水叶片分别进行快速水分胁迫和缓慢水分胁迫实验,结果表明,荧光比Rfd及动力学曲线上次峰值出现的时间随着胁迫的加剧均发生相应变化,且与叶片含水率之间具有较高的拟合决定系数。因此,将叶绿素荧光动力学特征和图像信息相结合,可提高植物干旱胁迫早期预测的准确度和直观性,为现场连续无损地监测植物生长状态、各类胁迫信息、病虫害检测等提供了一种快速的遥测手段。Chlorophyll fluorescence is a useful indicator as it gives important information about the stress and health state of plant. In order to detect plant water stress and growth state accurately and intuitively,plants under different drought stress conditions were experimented by using chlorophyll fluorescence imaging method combined with the chlorophyll fluorescence kinetics parameters. The chlorophyll fluorescence was excited by 460 nm LEDs,and acquired by EMCCD equipped with 690 nm band pass filter. The average pixel value was calculated for each image of 4 000 pictures which were acquired in four different sampling periods individually. The intensity of each image was plotted according to the time sequence,thus the chlorophyll fluorescence kinetics curve could be concluded, and chlorophyll fluorescence kinetics parameters could be calculated. Meanwhile, images were processed for noise reduction,calculation of multiplication and division and so on. And then they were displayed by pseudo color,thus various factors led to uneven distribution of fluorescence could be intuitively analyzed. Fast water stress and slow water stress experiments were conducted for easy to dehydrate and not easy to water loss leaves,respectively. The results showed that the fluorescence ratio Rfdand the time of second peak of kinetics curve were changed with the increase of stress,and both had high fitting determination coefficient with leaf water content（ 0. 86 and 0. 98）. Therefore,the method combined the chlorophyll fluorescence imaging with chlorophyll fluorescence kinetics parameters could improve the accuracy and intuition of plant drought stress earlier prediction,and it could be a rapid means of remote sensing for site continuous monitoring the growth status of plants,all kinds of stress,pest and disease and so on.

关 键 词：水分胁迫 叶绿素荧光成像 荧光动力学 

分 类 号：S123[农业科学—农业基础科学] S127