Modern Methods of Plant Analysis
01 Aug 1956-Journal of AOAC International (Oxford University Press (OUP))-Vol. 39, Iss: 3, pp 895-896
About: This article is published in Journal of AOAC International.The article was published on 1956-08-01. It has received 1823 citations till now.
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TL;DR: In this article, the spectral characteristics and absorption coefficients of chlorophylls, pheophytins, and carotenoids were analyzed using a two-beam spectrophotometer.
Abstract: Publisher Summary This chapter presents detailed information on chlorophylls and carotenoids to give practical directions toward their quantitative isolation and determination in extracts from leaves, chloroplasts, thylakoid particles, and pigment proteins. The chapter focuses on the spectral characteristics and absorption coefficients of chlorophylls, pheophytins, and carotenoids, which are the basis for establishing equations to quantitatively determine them. Therefore, the specific absorption coefficients of the pigments are re-evaluated. This is achieved by using a two-beam spectrophotometer of the new generation, which allows programmed automatic recording and printing out of the proper wavelengths and absorbancy values. Several procedures have been developed for the separation of the photosynthetic pigments, including column (CC), paper (PC), and thin-layer chromatography (TLC) and high-pressure liquid chromatography (HPLC). All chloroplast carotenoids exhibit a typical absorption spectrum that is characterized by three absorption maxima (violaxanthin, neoxanthin) or two maxima with one shoulder (lutein and β-carotene) in the blue spectral region.
10,367 citations
TL;DR: In this paper, the extinction coefficients for chlorophylls a and b in diethylether (Smith, J.H. and Benitez, A.V., eds.), used in this paper as primary standards, were verified by magnesium determination using atomic absorbance spectrophotometry.
5,326 citations
TL;DR: Many bioactive compounds are extranutritional constituents that typically occur in small quantities in foods and are grouped accordingly as phenolic compounds, including their subcategory, flavonoids as discussed by the authors.
2,091 citations
TL;DR: Salicylic acid is essential for the development of systemic acquired resistance in tobacco and was investigated in transgenic tobacco plants harboring a bacterial gene encoding salicylate hydroxylase.
Abstract: It has been proposed that salicylic acid acts as an endogenous signal responsible for inducing systemic acquired resistance in plants. The contribution of salicylic acid to systemic acquired resistance was investigated in transgenic tobacco plants harboring a bacterial gene encoding salicylate hydroxylase, which converts salicylic acid to catechol. Transgenic plants that express salicylate hydroxylase accumulated little or no salicylic acid and were defective in their ability to induce acquired resistance against tobacco mosaic virus. Thus, salicylic acid is essential for the development of systemic acquired resistance in tobacco.
1,731 citations