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The secret life of seeds

Many plant species reproduce by seed. Seeds come in many shapes and sizes, but inside each one is a tiny embryo, surrounded by structures ensuring the greatest chance of its survival.

By studying how different seeds germinate and develop into adult plants, scientists can better understand how plants regenerate and survive. This knowledge helps us to produce more plant species for horticulture and agriculture, and assists in the restoration of damaged ecosystems.

Seed germination
For some seeds, germination is simple; it is triggered by warmth and moisture. Other seeds have more complex needs, such as exposure to certain natural compounds or a sequence of different temperatures. To investigate the conditions needed by various plant species, seeds are germinated in special growth chambers.
 
Inside the temperature-controlled incubators, seeds germinate in small dishes filled with agar jelly (Image: ©Richard Weinstein)
 
Sleepy seeds
Some plants have seeds that remain dormant for many years. These seeds are waiting for the right conditions to germinate. For some species it is as simple as biding their time through several seasons. Other seeds may need a series of events, such as fire followed by rain. Once conditions that favour germination for each species are identified, plants are propagated by creating these conditions inside the laboratory.

Wattle (Acacia) embryos lie dormant inside a hard black seed casing that opens after fire or other germination triggers
 
X-ray vision
All seeds must be whole and undamaged to be of value for seed-banking. Newly collected seeds are x-rayed to makes sure they have an embryo which is necessary for germination. An x-ray also helps detect unwelcome visitors — insects and their larvae that devour seeds from the inside.
 
Seeds of a sedge (Carex fascicularis). Whole embryos appear as lighter areas on the x-ray.