Surely when we initially think about stress, plants do not come to mind. However, a curious fact is that plants are constantly stressed. In fact, if plants are not stressed then something is not right.
Plants suffer from a wide range of different stress agents during their whole growth cycle. Starting from the moment the seed germinates up to when the fruit is formed (and even packaged!).
To understand plant stress, it is important to differentiate between the two main types of stress: Abiotic and Biotic stress. The difference between both stresses, merely lies within the stress origin. Abiotic stress is due to climatic factors such as rain, high or low temperatures, wind, floods etc. Biotic stress on the other hand, are stresses with a biological origin. These types of stress are mainly due to pathogenic attacks by microbes or even signaled as a response to being eaten by herbivores.
Another factor that defines the stress is the magnitude of the stress, that is, how severe the stress is. It is not the same to suffer from a mild temperature change than to suffer from a severe drop in temperature, way out of the normal growth range of the plant. As is the case of diseases. The plant will react differently to an attack by few insects on a single leaf than to a massive widespread of a plague on itself and neighboring plants. In fact, scientists have shown that plants are able to “talk” to each other by airborne signals to warn their neighbors about an imminent attack.
The third factor that defines the stress is the duration of the stress. Different stresses can have different severities on the plants, but the duration of the stress, defines the damage that the stress can cause. Plants are well equipped to deal with stress situations. They have evolved to have different genes specialized to combat the different stresses. However, if the magnitude of the stress and the duration is so immense, the plant’s innate defense mechanisms will not be enough to fight off the stress. Even if the plants can overcome the stress, if the duration of the stress was great, then the plants might not completely recover from the damages produced. This opens the door for new possibilities of exogenously applying substances that can help improve the plants’ defense systems as well as recovery from the stress.
In brief, plants suffer from different types of stress both abiotic and biotic. These stresses can affect the plants more severely depending on the magnitude of the stress and their duration. Plants have evolved to have different defense mechanisms against the stresses, affecting both themselves as well as their neighbors through airborne signals. If plants did not develop their defenses, from seedlings to adults, then surely, they could not withstand the different stresses throughout their growth cycle.
In a world with an ever more present climate change, the question is, will plants be able to withstand climate change alone or will they need help?
By Abbas Caballero