Continuous Monitoring of the Photochemical Loss for in-vivo Plants Using an Open-Ended Photothermal Cell

An automated photothermal system has been developed to measure the photochemical loss of in vivo plant leaves. In this paper we present results obtained with a programmed system calibrated to measure the hourly photochemical loss during a period of one week (168 hours). To show the usefulness of our technique, we compare the results obtained for a plant maintained inside a receptacle containing a single solution of water and nutrients with the results obtained for another plant that was immersed in the same solution plus polyethylene-glycol to see the effect of water stress on the photochemical loss measurement. Our results indicate that the present technique permits a study of the response of in vivo plants submitted to different water stress conditions.