Detection of the effects of water stress on woody plants

Climate change is increasing the chronic water scarcity in many world regions, and also in Mediterranean basin. Water is the most limiting resource for plant growth and development where the climate is characterized by high potential evaporation and low and highly variable rainfall during the growing season. Water deficit constraints all the physiological processes involved in photosynthesis. In addition, drought and heat have effects on plats secondary metabolism as the synthesis and the emission of volatile organic compounds (VOCs) that, on global scale, are able to influence the chemical and physical properties of the atmosphere. Therefore, in last years has become important to develop methods enabling the detection and the description of water relations and the physiological responses of plants experiencing water stress, that could allow the monitoring on large scale of the effects of an increasing drought condition on the vegetation. In the present study phenotyping methods have been applied to monitor water relations, photosynthetic status and physiological responses in woody plants experiencing water stress. The aim of the study was to evaluate the reliability of remote sensing techniques, based on the passive analysis of spectral reflectance, to monitor the water status of plants and different functions that are affected by drought. Thereafter, a new application of these methods was tested for the detection of the indirect estimation of foliar isoprenoid emissions, in order to sense them remotely. In addition, the relationships and the interactions of chemical and hydraulic signals from root to leaves and the emission of VOCs were investigated in a partial root zone drought experiment on Populus nigra saplings.