Biospeckle optical coherence tomography in speedy visualizing effects of foliar application of plant growth hormone to Chinese chives leaves

Abstract

The aim of this study is to demonstrate the potential of applying the contrast of the speckles obtained as noise in optical coherence tomography (OCT) images to monitor short term activity changes during foliar application of phytohormones to a plant. Plant growth hormone, gibberellic acid (GA 3 ) was sprayed onto the leaf of Chinese chives and after 60 minutes, OCT images (1frame:512x2048pixles) were recorded at 10 frames per second for a period of 60 seconds. Contrast across the temporal axis was calculated for each pixel of the structural images and biospeckle OCT contrast images were obtained under the condition of before and after application of GA3 for different concentrations 0, 40, and 100 mM. Application of 40 mM GA 3 failed to show any differences in the OCT structural images; however, bOCT contrast image was clearly different. Although the mechanism for the contrast difference is not clear, it can be said there is a large change across the temporal scale with the application of GA 3 . This could be due to the changes in the leaf surface structures. Demonstration of OCT utilizing the speckle contrast is believed to have the potential as a promising tool in plant physiology.