Part 1: methods to analyse photosynthesis as the main process affecting crop productivity

In the quickly developing contemporary world, as well as due to the current climatic changes and the constantly increasing human population, the main aim of the agronomists is to increase agricultural productivity. Thus, there is a need for plant breeds and cultivars being more productive and better adapted to unfavourable environmental conditions. Stress factors exert a strong negative impact on plant productivity worldwide. Since photosynthesis is the main process, supplying plants with energy and carbon for the organic molecules needed for growth, its inhibition will affect productivity at the highest level. In addition, the disturbance of the light phase of the photosynthesis, could induce oxidative stress, as a secondary effect. Therefore, the precise regulation of photosynthetic activity is essential for stress tolerance and the increase of productivity. The aim of the current article was to present ways to collect and analyse data related to the effect of the stress factors on the photosynthetic apparatus and crop productivity. For this purpose, several methods for photosynthetic analysis have been described. These methods have the advantage of being non-invasive, which greatly reduces the time and cost of the analysis and allows multiple measures to be performed without the destruction of the plant. Moreover, they are sensitive enough to show changes in physiology after brief exposure to stress. Each of these methods describe a specific stage of photosynthesis. Therefore, using them jointly can greatly increase the information they provide, showing more details of the process.