Imaging of Chlorophyll a Fluorescence: A Tool to Study Abiotic Stress in Plants

In normal physiological conditions the fate of absorbed light by photosynthetic pigment is utilized for photosynthetic quantum conversion and only a small portion is de-excited via emission as heat or red and far-red chlorophyll fluorescence. By contrast, under many stress conditions the photosynthetic quantum conversion declines and concomitantly the chlorophyll fluorescence emission increases. For this reason, chlorophyll fluorescence analysis has long been an important tool for the estimation of a range of photosynthetic parameters in leaves. However, it is also known that changes in photosynthetic activity within leaves can be heterogeneous. In fact, the image of chlorophyll fluorescence have been revealed a heterogeneous response to changing light intensity, freezing, fungal or viral infection, ozone, water stress. For this reason, one of the major disadvantages of conventional chlorophyll fluorescence measurements is that it provides information only on a single leaf spot and is not representative of the physiological status of the whole leaf. By contrast, chlorophyll fluorescence imaging can allow detection of the early stages of many different types of stress, in particular when leaf samples are characterised by a large surface heterogeneity of chlorophyll fluorescence emission. Our research group studied from many years on the effect of biotic and abiotic stress on photosynthetic process. in this work we report some results that our research group have obtained. In particular we describe the effect of different abiotic stress on photosynthetic performance of some plant species.