Cauliflower’s response to drought stress

Background. Cauliflower has high water requirements due to the heavy weight of its leaves, so drought stress is one of main factors affecting plant growth and yield. The aim of this study was to determine the impact of drought stress on the physiological parameters of the cauliflower plant. Material and methods. Cauliflower plants cv. ‘Sevilla’ F1 were grown in containers filled with a peat substrate of different water contents i.e. 20%, 30%, 40%, 50% and 60% of field capacity. These parameters were measured: net photosynthetic rate, transpiration rate, chlorophyll fluorescence, stomatal conductance, intercellular CO2 concentration, and electron transport rate. Measurements were taken at the 5-leaf phase after 9 days of drought. Results. The lowest moisture level was observed at the substrate water content (SWC) of 20% of the field capacity and as a result, the plants grown in this substrate absorbed the smallest amount of water. At a 20% SWC, cauliflower plants showed the lowest photosynthetic rate, transpiration rate and stomatal conductance, while the CO2 content in substomatal cavities and electron transport rate were the lowest. However, there were no significant differences in chlorophyll fluorescence between all SWC levels. Conclusions. There was a significant correlation between the substrate water content and the physiological response of the plants to drought stress. Drought stress was delayed as the substrate water content increased. On the other hand, severe water deficit resulted in faster plant response to drought stress.