The Lazy Gardener

Gardening with Brenda Beust Smith

Mom & DNA — cuttings say it all!


A Happy Mother’s Day gift the perfect way to teach about plant DNA?

St. Thomas Episcopal School’s Life Science teacher Jane Doerries proved it’s so!

Above is one of her four 7th grade classes that rooted cuttings for their mothers for Mother’s Day gifts and in the process learned a lot about plant DNA.

Mrs. Doerries gathered cuttings from the antique rose beds of Texas Rose Rustlers Ursula White and Drew Meyers, making sure each cutting had at least four leaf nodes. Last year she chose ‘Puerto Rico’ (white), ‘Drew’s Rose’ (peach), ‘Maggie’ (Aggie-maroon), ‘Monsieur Tillier’ (red-pink), ‘Mrs. B. R. Cant’ (silvery pink) and ‘Dame de Coeur’ (deep red) — all good choices for rooting.

The idea was to teach her students that a plant’s DNA above the soil line produces leaves, while below the soil line the same DNA produces roots.

If it’s the same DNA, why don’t we get leaves in the dirt and roots in the air?

They learned about environmental triggers.

Below soil there is less oxygen and no sun. The genes that direct the cells to make leaves are quiet (quiescence) and the genes that direct the cells to make roots become active.

If there is a lot of oxygen and sun (above ground), genes that direct the cells to make roots are quiet and the ones that direct the cells to make leaves become active.

The lectures were far more complicated, of course, as the kids learned about taking cuttings, leaf nodes, rooting hormones and more. As pictured below, cuttings were soaked in Medina Plus and then stuck them in coco coir (a rooting medium), both of which are natural sources of rooting hormones.

The cuttings were placed first in clear cups, with drain holes, and then those cups were inserted into black cups to cut off all sunlight (stimulating an under-soil environment). Remaining leaves were cut in half to decrease the demand for water and nutrients to support the leaves but still allow some photosynthesis to take place.

The cups were set outside in bright shade and watered regularly. Later on the students were able to pull the clear cups out and easily see the roots that had formed.

It took about two months and, of course, not all survived.  But enough did so that each student had a rooted cutting to transfer to a decorated pot for Mom.


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The Lazy Gardener

4 Responses

  1. Audrey McMurray says:

    Mrs. Doerries works really hard to make science fun for her kids and they are crazy about her! Kudos to her!

  2. Tim Russell says:

    Mrs. Doerries does a very professional job teaching her Life Science course to our 7th graders. They are very prepared to come into 8th science and on to high school biology.

    Tim R.

  3. Amy Ernest says:

    Jane is indeed an accomplished educator and a lovely role model for her students. I know that they will remember this experiment, and maybe take up gardening themselves someday!

  4. Beth Ducker says:

    My daughter adores Mrs. Doerries and so enjoyed her class. The rose cuttings were a huge hit. Thank you for making science enjoyable!