Lesson 2 - Barley

The embryo contains living cells and the precursor tissue to the first leaf, stem and roots.

The two main components of the embryo are the axis and the scutellum. Within the axis, the first leaf is encased in the coleoptile; the first roots (chits) are in the coleorhiza. The embryo must be alive and intact for the grain to germinate.  

Figure: Barley embryo stained with tetrazolium salts

Embryo composition

The embryo is 3-4% of the total dry grain weight.

• ~ 34% protein
• ~ 13-17% triglycerides
• ~ 16% cell wall and polysaccharide gums
• ~ 14-15% sucrose
• ~ 5-10% raffinose
• ~ 5-10% ash
• ~ 7% pectin and hemicelluloses (polysaccharides with a different branched structure to cellulose)
• B-group vitamins

If the embryo is alive, it stains pink when treated with tetrazolium salts as shown above. This can be used as a quick test before barley is accepted at the maltings.