Plants can also respond to environmental factors using other hormones.
Gibberellins
gibberellinA plant hormone involved in germination, flowering and fruit formation. are a group of plant hormones responsible for growth and development.
Gibberellins can be used to:
end seed dormancyHibernation for seeds which stops when they germinate.
promote flowering
increase fruit size
Seed dormancy must be broken for seeds to germinate. Gibberellins are important for initiating seed germinationThe process where seeds sprout and begin to grow. in response to the seed being exposed to water.
They also stimulate cell elongationBecoming longer. and cause plants to grow taller.
Gibberellins cause boltingThe early production of flowers caused by gibberellins as a response to cold or a lack of water., the production of flowers in an attempt for the plant to be able to reproduce before it dies. Bolting can happen if it is cold or there is a lack of water.
Gibberellins are naturally produced by seeds.
Fruit ripening
ethene The simplest alkene, consisting of two carbon atoms joined by a double bond, surrounded by four hydrogen atoms. is a hydrocarbonA compound that contains hydrogen and carbon only. gas which speeds up ripening in bananas and other fruit as well as causing dropping of leaves. It also controls cell division during plant growth.
In the food industry fruit is often picked unripe and then transported. This prevents fruit from over-ripening on the journey. It is ripened during storage by adding ethene and then taken to the shops.
The effect of ethene released from bananas is clearly visible if you keep them in a bowl with other fruit, as it causes other fruits to ripen very quickly.