Plant responses to climate change

 

   Plant responses to climate change

Source: Pixabay

What will be the future climate?

Temperature and precipitation patterns are changing all over the world as a result of increased CO2 levels in the atmosphere. The rate of climatic change over the next century is expected to be faster than in the past. The Intergovernmental Panel on Climate Change (IPCC) estimates that at current rates of emissions, carbon dioxide levels in the atmosphere will double or triple in the next century, and the climate system will respond.

Climate scientists predict that regional climatic changes will vary due to different response rates. Climate models, for example, predict that some areas will receive more precipitation than others. Scientists predict that the following changes will occur within decades to hundreds of years.

C3 plants

C3 plants lack photosynthetic adaptations that reduce photorespiration. C3 plants only use the standard carbon fixation mechanism. (Rubisco's carbon dioxide fixation.) C3 plants account for approximately 85% of all species on the planet. Rice, wheat, soybeans, and other trees are some examples.

C4 plants

In C4 plants, the light-dependent reactions and the Calvin cycle are physically separated. Light-dependent reactions take place in mesophyll cells, while the Calvin cycle takes place in bundle sheath cells. About 3% of all vascular plants use the C4 pathway. Maize, millet, sorghum, and sugar cane are a few examples.

CAM plants

To reduce photorespiration, these plants use the crassulacean acid metabolism (CAM) pathway. This name is derived from the crassulacean plant family, in which scientists first discovered the pathway. These plants have adapted to dry conditions. Cacti and pineapples, for example. Plants that use CAM photosynthesis use very little water. Their stomata open only at night. When humidity levels are high and temperatures are low, water loss from leaves is reduced. These plants are typically dominant in extremely hot, dry environments such as deserts.

 Climate change has a wide range of effects on plants, including heat waves, increased flooding, and droughts. Aside from the indirect effects of global warming, rising CO2 concentrations and temperatures have a direct impact on plant growth, reproduction, and resilience. It is difficult to predict the effects on natural vegetation and agriculture.

In theory, higher CO2 levels should stimulate photosynthesis in certain plants. A doubling of CO2 levels may increase photosynthesis rates by 30-100%. This is especially true of C3 plants. Increased CO2 levels tend to suppress photorespiration in these plants, allowing them to use less water. C4 plants, on the other hand, would not respond as dramatically (although at current CO2 levels, these plants photosynthesize more efficiently than do C3 plants).

Even if the temperatures are below a plant's optimal temperature, higher temperatures are not always optimal for yield. Plants grow faster at higher temperatures, which reduces the amount of time for photosynthesis and growth, resulting in smaller plants, and two, reduces the time for grain fill, resulting in lower yield, especially if nighttime temperatures are high. High temperatures can also reduce pollen viability and make pollen lethal.

Drought alone causes more crop yield loss per year than all pathogens combined. Plants change their physiology, modify root growth and architecture, and close stomata on their aboveground segments to adapt to moisture gradients in soil. These tissue-specific responses alter the flux or cellular signals, resulting in early flowering, stunted growth, and, in many cases, reduced yield.