Plants are living organisms sensitive to the conditions of their environment. During evolution, they have developed different response and adaptation mechanisms to adverse environmental situations around them (also called stress). This is how they manage to survive and reproduce.
But climate change represents a new scenario. Situations such as extreme temperatures and prolonged periods of drought or flooding are some of the environmental factors increased by this phenomenon that significantly limit their growth, development, productivity and survival.
How do plants react to stress?
There is a wide variety of biochemical, molecular and physiological mechanisms of plants in response to stress. Typically, these responses include:
- changes in their growth and metabolism.
- physiological changes such as the regulation of the opening of the stomata – the pores through which they absorb and expel gases and water –.
- changes in the expression of genes, including those that code for proteins with protective function, antioxidants and transcription factors that control the expression of stress-response genes.
These responses, in turn, may depend on the synthesis of plant hormones such as abscisic acid, salicylic acid or jasmonic acid. Changes in the concentration and distribution of these plant hormones modulate development and responses to stress. This set of responses, normally specific to each stressor, has been widely studied by the scientific community.
However, due to climate change, there may be combinations of adverse conditions that further harm plants and their production. The increase in temperatures will coincide with other environmental factors such as drought, high light intensity, salinity and nutritional deficiencies, among others.
Recent studies have focused on plant responses to different combinations of two stresses that frequently occur simultaneously – for example, high temperature and drought, high light intensity and high temperature, or salinity and high temperature. They showed that the physiological, biochemical and molecular responses of plants to these combinations are specific and different from responses to individual conditions.
Climate change, a new concept of stress for plants
Studying how plants react to new situations in their environment is crucial for developing crops that are more tolerant to climate change. Studies should focus on plant responses to situations most likely to occur in the context of global warming.
Each of these stresses has a negative effect on plants, but the simultaneous interaction of more than two factors – a multifactorial combination of stresses – creates a new and critical situation for plant growth and survival.
For example, during summers, the combination of heat waves and extreme dry spells, as well as suboptimal soil conditions due to excessive salinity, poor nutrient content, or the presence of microplastics , herbicides and pesticides, put the survival of many crops in certain regions at risk.
We have recently shown that the combination of up to six factors – high temperatures, high light intensity, salinity, acidity, heavy metals and herbicides – applied simultaneously in different combinations causes a decrease in the growth and survival of model species. Arabidopsis thaliana.
Thus, while one or even two stresses may not have a significant effect on an agricultural area or ecosystem, the addition of several factors (each with no apparent effect when applied individually) could lead to an unexpected decrease and dramatic effect on plant yield and survival. . This fact suggests that in nature, we may not be able to predict how different stresses affect plants or an ecosystem until it is too late.
The conclusions drawn from studies of multifactorial combinations of stress should serve as a warning to society: if we do not limit the number and intensity of the different stresses associated with climate change that we introduce into our environment, we may head being towards a planet that does not support climate change rapidly increasing the growth of our species.
How to improve crop yields
The alarming findings in the factory Arabidopsis thaliana They need to be corroborated by further studies looking at the responses of different plant species, microbiomes and crops to combinations of stresses.
From multidisciplinary approaches, we can mitigate the negative effects in relation to agricultural production. These should include plant breeding and engineering to develop resistant varieties, increase the biodiversity of crops used in agriculture, and manipulate plant-microbiota interactions.
Such an approach would integrate laboratory, growth chamber, greenhouse and field experiments to assess plant responses through genome-wide association studies of different crops and species.
In addition, other areas of research, such as materials science, nanotechnology, physics and chemistry, as well as the use of advanced methods of precision agriculture, could complement the improvement and protection work. plants and crops against the devastating effects of climate change.
Knowing how the different genes, hormones and metabolites that regulate each of the plant responses to stress interact with each other and how they interact during multifactorial combinations of stress is essential for producing plants tolerant to combinations of environmental factors. The road is long and time is running out.
Reference article: https://theconversation.com/even-we-don’t-know-if-the-plants-will-be-able-to-adapt-to-climate-change-185735