Ecophysiology

[citation needed] In many cases, animals are able to escape unfavourable and changing environmental factors such as heat, cold, drought or floods, while plants are unable to move away and therefore must endure the adverse conditions or perish (animals go places, plants grow places).

It is hypothesized that this large number of genes can be partly explained by plant species' need to live in a wider range of conditions.

Metabolic imbalances associated with temperature extremes result in the build-up of reactive oxygen species, which can be countered by antioxidant systems.

Plants can avoid overheating by minimising the amount of sunlight absorbed and by enhancing the cooling effects of wind and transpiration.

These features are so common in warm dry regions that these habitats can be seen to form a 'silvery landscape' as the light scatters off the canopies.

The same principle has been applied in agriculture by using plastic mulch to insulate the growing points of crops in cool climates in order to boost plant growth.

This remarkable mechanism allows plants to lift water as high as 120 m by harnessing the gradient created by transpiration from the leaves.

The use of this technique was largely developed by Dr Peter Dry and colleagues in Australia[10] If drought continues, the plant tissues will dehydrate, resulting in a loss of turgor pressure that is visible as wilting.

As well as closing their stomata, most plants can also respond to drought by altering their water potential (osmotic adjustment) and increasing root growth.

Plants that are adapted to dry environments (Xerophytes) have a range of more specialized mechanisms to maintain water and/or protect tissues when desiccation occurs.

[citation needed] The concentration of CO2 in the atmosphere is rising due to deforestation and the combustion of fossil fuels.

Extensive experiments growing plants under elevated CO2 using Free-Air Concentration Enrichment have shown that photosynthetic efficiency does indeed increase.

[13][14] However, detrimental impacts of global warming, such as increased instances of heat and drought stress, mean that the overall effect is likely to be a reduction in plant productivity.

This is known as the boundary layer and in effect insulates the leaf from the environment, providing an atmosphere rich in moisture and less prone to convective heating or cooling.

On the other hand, a moderately high wind allows the plant to cool its leaves more easily when exposed to full sunlight.

In fact, leaf and canopy dimensions are often finely controlled to manipulate the boundary layer depending on the prevailing environmental conditions.

This signal leads to inhibits the elongation and stimulates the radial expansion of their shoots, while increasing the development of their root system.

This syndrome of responses known as thigmomorphogenesis results in shorter, stockier plants with strengthened stems, as well as to an improved anchorage.

[26] When this type of disturbance occurs in natural systems, the only solution is to ensure that there is an adequate stock of seeds or seedlings to quickly take the place of the mature plants that have been lost- although, in many cases, a successional stage will be needed before the ecosystem can be restored to its former state.

This is necessary because in order for enzymes to function, blood to flow, and for various body organs to operate, temperature must remain at consistent, balanced levels.

Cold stress is physiologically combated by shivering, accumulation of body fat, circulatory adaptations (that provide an efficient transfer of heat to the epidermis), and increased blood flow to the extremities.

The respiratory system protects itself against damage by warming the incoming air to 80-90 degrees Fahrenheit before it reaches the bronchi.

Rahn's research into applications of this diagram led to the development of aerospace medicine and advancements in hyperbaric breathing and high-altitude respiration.

Rahn later joined the University at Buffalo in 1956 as the Lawrence D. Bell Professor and Chairman of the Department of Physiology.

As Chairman, Rahn surrounded himself with outstanding faculty and made the University an international research center in environmental physiology.