Carbon dioxide concentrations are very high in developing oilseeds

Area of Science:

• Plant Physiology
• Biochemistry
• Seed Development

Background:

• Developing seeds accumulate significant carbon compounds for growth and storage.
• Understanding carbon dynamics within seeds is crucial for crop yield and quality.
• Previous methods for measuring seed carbon were time-consuming and less sensitive.

Purpose of the Study:

• To develop and validate a rapid method for quantifying total inorganic carbon in developing seeds.
• To determine the concentration of total inorganic carbon in developing rapeseed and soybean seeds.
• To investigate the dynamics of carbon dioxide accumulation during seed maturation.

Main Methods:

• Seeds were rapidly dissected and homogenized in 1 N HCl within gas-tight vials.
• Headspace gas from homogenized samples was analyzed using infrared gas analysis.
• The method was applied to developing seeds of rapeseed (Brassica napus L.) and soybean [Glycine max (L.) Merr.].

Main Results:

• A novel, rapid method for determining total inorganic carbon (TIC) in developing seeds was established.
• Developing rapeseed and soybean seeds contained high concentrations of TIC, reaching up to 40 mM and 12 mM, respectively.
• These seed TIC levels were 600-2000 times higher than those found in ambient air or plant leaves.
• Carbon dioxide concentrations in rapeseed peaked during maximum oil synthesis and decreased as seeds matured.

Conclusions:

• The developed method provides a rapid and sensitive means to assess inorganic carbon in developing seeds.
• Developing seeds represent a significant sink for inorganic carbon, with implications for seed metabolism and carbon economy.
• The observed high carbon concentrations suggest unique physiological roles and metabolic pathways within developing seeds.