Summer dormancy in perennial temperate grasses.

Area of Science:

• Plant Physiology
• Ecology
• Agronomy

Background:

• Summer dormancy is a critical survival strategy for perennial grasses in arid regions, yet it is less understood than winter dormancy.
• This review focuses on summer dormancy in Mediterranean perennial grasses, aiming to standardize terminology for this trait.

Purpose of the Study:

• To review current knowledge on summer dormancy in perennial temperate grasses from the Mediterranean Basin.
• To propose a unified terminology for describing summer dormancy in these grasses.
• To highlight the importance of summer dormancy for plant survival and cultivar development.

Main Methods:

• The study defines summer dormancy based on four criteria: reduced leaf production/expansion, foliage senescence, organ dehydration, and resting organ formation.
• Two levels of dormancy are proposed: complete (full senescence, dehydration) and incomplete (partial inhibition, moderate senescence).
• The review synthesizes existing research on the physiological and environmental factors influencing summer dormancy, distinguishing it from dehydration tolerance.

Main Results:

• Summer dormancy is characterized by reduced growth, foliage senescence, and organ dehydration, often influenced by photoperiod, temperature, and hormonal control.
• Dehydration tolerance and dormancy are distinct adaptive mechanisms.
• Summer dormancy is an endogenous (endo-) dormancy, observable under non-limiting moisture conditions.

Conclusions:

• Summer dormancy is strongly correlated with enhanced survival in perennial grasses subjected to severe and recurrent summer drought.
• This trait holds significant potential for developing new cultivars adapted to increasing aridity and meeting agronomic/environmental objectives.
• Further research into the genetic and environmental controls of summer dormancy is crucial for its effective utilization.