The Physiological Effects of Heat Stress on Plants
Physiological effects of heat stress
While the physiology of plant thermotolerance has been studied extensively in the last few decades, complete understanding of its mechanisms still eludes scientists. Heat stress affects plants differently from species to species and at different developmental stages. Despite this, plants can adapt to a range of temperature regimes. For example, some plants are highly sensitive to heat stress during flowering time. In addition, a short period of high temperatures can significantly reduce floral buds and result in flower abortion.
Physiological effects of heat stress in plants involve the accumulation of ROS on the outer surface of the plasma membrane. This leads to membrane depolarization, activation of Ca-induced RBOHD, and induction of programmed cell death. The accumulation of ROS has numerous negative effects on plant metabolism and development. As a result, plants have evolved a tolerance to heat stress through a variety of mechanisms.
Heat damage increases the probability of degradative molecular interactions and the development of stress-induced oxidative damage in plants. Consequently, the plant system uses several types of proteins to adapt to heat. Several proteins of the heat shock family are responsible for this protective mechanism. In plants, these proteins regulate the expression of multiple genes within the plant cell and coordinate their expression in different pathways. They also protect intracellular proteins from denaturation by promoting the folding of proteins and their function by acting as chaperones.
Signaling pathways involved
Heat stress induces changes in the synthesis of certain proteins, known as heat shock factors, which are essential for plant recovery from radiation and high temperatures. These proteins play multiple roles in signaling, including transcriptional induction of genes involved in heat stress response. Molecular mechanisms that regulate heat-stress responses are still under investigation, but this work has already demonstrated that some genes are involved in multiple processes. Here, we will discuss some of these pathways and the mechanisms that may underlie their physiologic functions.
Various environmental stresses such as drought, heat, and heavy metal toxicity can have a profound impact on plant growth, and may even cause a collapse of entire ecosystems. Plants respond to these stresses through canonical mechanisms known as stress-induced systemic signaling and systemic acquired acclimation. These pathways cause the plant to mount a comprehensive systemic response to the stressors and accumulate a wide variety of transcripts and metabolites. In addition, they also increase the number of stomatal cells in their leaves.
Several studies have indicated that BES1 is unable to increase the level of HSP-LUC, suggesting that it acts through indirect mechanisms. This is in contrast to a previous finding showing that BES1 is responsible for the activation of PP2C-type proteins in response to heat stress. It has also been shown that ABA negatively affects the function of BR-responsive growth and dephosphorylation of BES1/BZR1.
As global warming and other factors contribute to increased high temperature damage, treatment options for heat stress in plants are increasingly important. In particular, pre-treatment with a moderate heating regime can induce plant thermotolerance. In plants, this results in reduced levels of photosynthesis and damage to the electron transport system. This process occurs through oxidative stress and has been linked with plant survival. Despite the complexity of identifying a treatment option for heat stress in plants, there are some promising treatments that have been demonstrated to reduce or eliminate the effects of high temperatures on crop yields.
If you notice signs of heat stress in plants, it’s important to diagnose and treat the problem as soon as possible. While the specific steps vary, a few simple practices can help. Fungicides and insecticides are good options. You can also consider changing your gardening practices. If you’re unsure about which treatment options are best for your plants, consider contacting a local nursery or extension office for advice.
Pretreatment of plants with 30degC can partially reduce the effect of oxidative damage, but it did not improve survival rates. Treatment with 40degC may be necessary for the plants to survive after heat stress, as the pretreatment may inhibit the production of essential proteins for photosynthesis. The etr-1 mutant has a decreased survival rate compared to plants in the Columbia background ecotype. Furthermore, it shows greater levels of oxidative damage compared to the untreated control group.