En EspaŅol

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
    
 
See a list of all Smarty Plants questions
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
 
rate this answer
Not Yet Rated

Wednesday - November 22, 2006

From: Leander, TX
Region: Southwest
Topic: Propagation
Title: Breaking dormancy of native seeds
Answered by: Nan Hampton

QUESTION:

The science of seed preservation seems to be well advanced. However, Jill Nokes' book appears to be the only well-known information about breaking dormancy of native seeds. I'm grateful that she wrote that book, but it is more of a anecdotal collection than a scientific study, so I would appreciate any further sources of information that you encounter. If you can answer, or forward this question to the appropriate person, I would certainly appreciate it: Is stratification, either warm or cold, a biological process that requires imbibation in order to proceed? In other words, should a seed be scarified BEFORE stratification? This is confusing to me because all texts seem to treat storage SEPARATELY from preparation for germination, while in nature it's all one complex, variable process. Obviously, since my objective is to propagate, I need to perform specific actions at specific times to replicate the "natural" requirements of a species. More than you expected, I guess........, but thanks for any help.

ANSWER:

Seeds with tough impermeable coverings need a break in that seed coat in order to allow moisture to enter to begin the germination process. Seed scarification occurs naturally from environmental sources—abrasion from the soil, frost, fire, passing through the digestive system of animals, etc.—but this is more or less a random process. We can intervene and speed up the process by scarifying batches of these tough-coated seeds before they are planted. There are several methods: mechanical—abrading by sandpaper, knife, etc.; soaking in water; and treating with acid. Stratification, either cold or warm, involves storing the seeds in a moist medium, such as sand, for a period of time to break the physiological dormancy. Indeed, seeds with tough coats need to be scarified before stratification so that they can take advantage of the moisture in the stratification medium. Several studies have reported both increased speed and amount of germination by scarifying and then stratifying seeds. For example:

Kaye, T. N. "Effects of scarification and cold stratification on seed germination of Lupinus sulphureus ssp. kincaidii." Seed Science and Technology (2001), v. 29(3), p. 663-668. A combination of scarification and stratification increased germination by as much 95%.

Syn,. Y. C. et al. "NaOH scarification and stratification improve germination of Iris lactea var. chinenesis." HortScience (2006 June) v. 41(3), p. 773-774. Germination improved by 80% using both treatments together.

Geneve, R. L. "Seed dormancy in Eastern redbud (Cercis canadensis)." (Jan. 1991), v. 116(1), p. 85-88. From the abstract: "Seed dormancy in Eastern redbud (Cercis canadensis var. canadensis L.) can be overcome by seedcoat scarification to allow water imbibition, followed by chilling stratification to permit germination."

Qrunfleh, M. M. "Studies on the hawthorn (Crataegus azarolus L.): I. Seed germination as influenced by scarification and stratification." Dirasat Series B Pure and Applied Sciences (1993) v. 19(4), p. 7-18. Acid scarification combined with warm stratification increased germination by 10%.

Stratification requirements and techniques differ for various plants and some do not benefit particularly from stratification. However, if the seeds would benefit from stratification, either cold or warm, and they have an impermeable coat, the bottom line would seem to be scarify first and then follow with stratification.

You can find a good article on seed germination and dormancy from Texas Tech University Department of Plant and Soil Science.

 

More Propagation Questions

Care and propagation of Kentucky Coffeetree
December 22, 2006 - I found a tree on our property in Missouri, after some reserch I found that it is a Kentucky Coffee tree. I collected several of the pods and would like to know how I can plant them to grow. Thanks.
view the full question and answer

Best place for picking wildflowers in Austin
February 14, 2014 - Where is the best place to find wildflowers for picking near or in Austin around the end of March?
view the full question and answer

Propagation of Kalmia latifolia
November 19, 2007 - How easy is it to propagate Kalmia latifolia from seed?
view the full question and answer

Standing Cypress Plants in San Antonio, TX
June 26, 2013 - I purchased seeds for standing cypress 2 years ago and this spring they look beautiful. What is the best way to harvest the seeds? Also, will the current plants come back next spring or will I have to...
view the full question and answer

Restoring the woods in Central Austin.
May 08, 2012 - I live in Austin, south central between Red Bud trail close to the low water bridge and Bee Caves road. My question: I want to make the wooded sections of my yard attractive. They have filtered sun...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP
© 2014 Lady Bird Johnson Wildflower Center