Cold, heat, drought, frost, hail...


Emphasising factors caused by low temperatures (stress due to cold or frost) or high temperatures (stress due to heat wave)

Below or above a certain temperature, depending on the plant, plants suffer severe damage that constrains their optimum performance. Exposure to cold paralyses enzyme activity and induces a lowering of the fluidity of the cellular membranes, so that the transport of water and nutrients through them can be affected and the plant can stop producing. If the lowering of the temperature is intense and sudden the plant runs the risk of freezing, which results in the formation of ice crystals inside the cell, which will cause severe cellular dehydration. 

On the other hand, prolonged exposure to extremely high temperatures damages the cell due to enzyme deactivation and protein denaturation, which leads to an increase in the fluidity of the cell membranes, i.e. the permeability of solutes through them is altered. Heat intensifies plant respiration relating to photosynthesis, which can paralyse growth. 
In the Mediterranean climate, the summer temperatures are high and tend to be accompanied by a severe drought. 

Water stress can be caused both by a lack of water (drought) and by an excess of water (root asphyxia). By way of example, the first is caused when the plant's transpiration is greater than its water absorption. One of the first manifestations is the loss of cell turgor, which leads to the dehydration of the cell, stomata closure and a lowering of photosynthetic capacity. 

Lastly, there is physical damage caused by weather agents such as wind or hail, which breaks parts of or all of the plant with the resulting delays in or losses of production this entails.