Middleton Elizabeth M, Kim Moon S, Krizek Donald T, Bajwa Ravinder K S
Biospheric Sciences Branch, NASA/Goddard Space Flight Center, Greenbelt, MD, USA.
Photochem Photobiol. 2005 Sep-Oct;81(5):1075-85. doi: 10.1562/2005-04-25-RA-498.
A growth-chamber experiment was conducted to evaluate whether ethylenenediurea (EDU), a chemical shown to be protective against ozone pollution, could ameliorate foliar damage induced by ultraviolet-B (UV-B) radiation exposure in 'Roanoke' soybean (Glycine max L.), a UV-B-sensitive cultivar, and whether these effects could be discriminated using fluorescence (F) observations. The experiment had four treatment groups: control; biologically effective UV-B (18 kJ m(-2) day(-1)); EDU (500 micromol mol(-1)); and both UV-B and EDU (UV/EDU). Measurements included photosynthetic pigments, F image system (FIS) images of adaxial surfaces in four spectral regions (blue, green, red and far-red) and F emission spectra of the pigment extracts produced at two excitation wavelengths, 280 nm (280EX) and 380 nm (380EX). Several F ratios from 280EX, 380EX and the FIS images successfully separated the low UV vs high EDU group responses based on means alone, with intermediate values for controls and the combined UV/EDU groups. A UV-B/blue emission ratio, F315/F420 (280EX), was correlated with chlorophyll content (microg cm(-2))(R = 0.88, P < 0.001), as was a ratio of emissions at two UV-A wavelengths: F330/F385 (280EX) (R = 0.87). These two 280EX ratios were also linearly correlated with emission ratios produced by 380EX, such as the far-red/green ratio, F730/F525 (380EX) (R = 0.92, P < 0.001), and clearly distinguished the UV-B and EDU groups separately, and which bracketed the similar intermediate responses of the UV/EDU and control groups. The FIS images additionally captured the following anatomical spatial patterns across the leaf surfaces: (1) emissions of UV-B-irradiated leaves were more uniform but lower in intensity than those of other groups; and (2) emissions of EDU-treated leaves exhibited the greatest variation in spatial patterns because veins had elevated blue F and leaf edges had enhanced red and far-red F. This experiment supports the hypothesis that EDU substantially ameliorated UV-B damage to foliage, a result that relied on the combined use of FIS images and emission spectra.
进行了一项生长室实验，以评估乙烯二脲（EDU）（一种已证明对臭氧污染具有保护作用的化学物质）是否可以改善对紫外线B（UV-B）辐射敏感的“罗阿诺克”大豆（Glycine max L.）因暴露于UV-B辐射而引起的叶片损伤，以及是否可以通过荧光（F）观测来区分这些影响。该实验有四个处理组：对照组；生物有效UV-B（18 kJ m(-2) 天(-1)）；EDU（500 μmol mol(-1)）；以及UV-B和EDU（UV/EDU）同时处理组。测量包括光合色素、四个光谱区域（蓝色、绿色、红色和远红光）中叶片正面的F图像系统（FIS）图像，以及在两个激发波长280 nm（280EX）和380 nm（380EX）下产生的色素提取物的F发射光谱。来自280EX、380EX和FIS图像的几个F比率仅基于平均值就成功地将低UV组与高EDU组的响应区分开来，对照组和UV/EDU组合组的值处于中间。UV-B/蓝色发射比率F315/F420（280EX）与叶绿素含量（μg cm(-2)）相关（R = 0.88，P < 0.001），两个UV-A波长处的发射比率F330/F385（280EX）也是如此（R = 0.87）。这两个280EX比率也与380EX产生的发射比率线性相关，例如远红光/绿色比率F730/F525（380EX）（R = 0.92，P < 0.001）它们清楚地分别区分了UV-B组和EDU组，并且将UV/EDU组和对照组类似的中间响应括在中间。FIS图像还捕捉到了整个叶片表面的以下解剖学空间模式：（1）UV-B照射叶片的发射更均匀，但强度低于其他组；（2）EDU处理叶片的发射在空间模式上表现出最大的变化，因为叶脉的蓝色F升高，叶边缘的红色和远红光F增强。本实验支持以下假设，即EDU可显著减轻UV-B对叶片的损伤，这一结果依赖于FIS图像和发射光谱的联合使用。
