The germination process of a dicot seed

  Added by: snoofer  Last edited by: snoofer  Viewed: 736 times   Rated by 19 users: 7.58/10
Contributed by: backyardchemist5
Submitted: 08-10-2003
Image archived: 2003
1. All of the following conditions must be present for seed germination:
a. Temperature
b. Moisture
c. Oxygen

2. The seed starts absorbing water by imbibition. Water swells the seed coat and brings the dormant plant inside the seed back to life.
3. The testa (seed coat) cracks.
4. The ratticle emerges from the seed, and forms into the root.
5. The hypocotyl elongates, pushing the 2 cotyledons above ground. As the cotyledons are pushed above ground, the testa fall off.
6. The plant uses up energy stored in the endosperm as it produces leaves and extends its root structure. The cotyledons (photsynthetic in marijuana) photsynthesize as they emerge, and continue supplying the seedling with energy until they undergo abscision and fall off.
Once the true leaves are formed, photosynthesis becomes the primary energy source, and growth becomes much more rapid.
Note: Marijuana seeds are ?dicots? (termed because they have 2 cotyledons).
[Editor?s note: Temperature can have a dramatic effect on the rate of germination.]

The process of etiolation
Etiolated plants have not yet been exposed to light and grow (typically) with a 'shepards crook' shape to protect the cotyledons (or leaves, depending on the case) as they are pushed through the soil (skotomorphogenesis).

Upon exposure to light, phytochromes within the leaves/cotelydons trigger the process of 'de-etiolation'. The 'shepards crook' straightens out (photomorphogenesis) and the plant starts to produce chlorophyll.

  Last modified: 16:29 - Nov 09, 2003  

faq:1584 "The germination process of a dicot seed"