The relationship between water binding and desiccation tolerance in tissues

Area of Science:

• Plant Physiology
• Biophysics
• Biochemistry

Background:

• Desiccation tolerance is a crucial trait for plant survival in arid environments.
• Understanding the biophysical mechanisms of water binding is key to defining desiccation tolerance.

Purpose of the Study:

• To compare water sorption characteristics between desiccation-resistant and desiccation-sensitive plant tissues.
• To elucidate the role of tightly bound water in desiccation tolerance.

Main Methods:

• Water sorption isotherms were generated for soybean axes and Polypodium fronds.
• Water binding strength was analyzed using van't Hoff and D'Arcy/Watt methods at varying temperatures.
• The effect of water removal on seed viability was assessed.

Main Results:

• Desiccation-sensitive tissues exhibited a limited ability to bind water tightly.
• Removal of tightly bound water (region 1 water) from soybean and pea seeds reduced viability.
• Region 1 water, characterized by highly negative enthalpy values, was identified as critical.

Conclusions:

• Tightly bound water is a significant component of desiccation tolerance.
• The capacity to retain region 1 water is essential for maintaining tissue viability during dehydration.
• This study provides insights into the molecular basis of plant desiccation tolerance.