Night-Time Transpiration - Favouring Growth?

Area of Science:

• Plant physiology
• Circadian biology
• Water relations

Background:

• Plants transpire water and respire carbon dioxide (CO2) both day and night.
• Night-time transpirational water loss is linked to CO2 efflux through stomata.
• This efflux supports respiration, which fuels night-time leaf expansion using stored carbohydrates.

Purpose of the Study:

• To investigate the regulation of night-time transpiration by the plant's internal clock.
• To understand the trade-offs between water loss and carbon gain during night-time growth.
• To explore the potential role of night-time transpiration in plant stress acclimation.

Main Methods:

• Physiological measurements of transpiration and CO2 exchange.
• Analysis of carbohydrate metabolism and its link to growth.
• Investigating the influence of circadian rhythms on these processes.

Main Results:

• Night-time transpiration is significantly influenced by the plant's internal clock.
• Water loss at night is a consequence of stomatal opening for respiratory CO2 release.
• This process optimizes water use for leaf expansion, despite the cost of water loss.

Conclusions:

• Plant circadian clocks regulate night-time transpiration.
• Night-time transpiration balances water loss against the benefits of efficient growth and potential stress acclimation.
• Understanding this mechanism is crucial for improving plant water-use efficiency and resilience.