So for those of you who havn't seen my post in the education section I'm an undergrad student in horticulture at NCSU and I've started a few research projects. The first involves mutagenesis of Sarracenia and the description of that is in the education section. The second is a study of the effects of wounding, cytokinin, and auxin on leaf cuttings of D. capensis. My partner and I took thirty cuttings for each of the five treatments. So in total 150 cuttings. The first treatment is the control in which we just lay the cuttings on the media which is a 1:1 peat and milled sphagnum mix. The second treatment was a wounding treatment where we used a razor blade to make a cut down the mid-vein of the leaf. The third treatment was a wounding treatment where we used a needle to poke holes on either side of the midvein covering most of the leaf. The fourth treatment is a liquid cytokinin dip where we dipped the entire leaf into a 250ppm cytokinin formulation. The fifth treatment is a liquid auxin dip where we dipped the entire leaf into a 500ppm auxin formulation.
We have checked on the cuttings every week and today we found buds forming on a few of the cuttings. I can't say which treatment is yielding the best results because truthfully i dont know. The treatments are labeled randomly with numbers to reduce bias. However we have some leaves that are producing up to 11 buds on a single leaf. I'll keep you all updated when there is more information!
We would if we had enough of other species to do replications but we don't. So at this point we'll leave that up to whomever wants to pick up where we leave off. However, it looks like this summer we're going to do another study where we use water as the media instead of a peat/sphagnum mix
The first treatment is the control in which we just lay the cuttings on the media which is a 1:1 peat and milled sphagnum mix. The second treatment was a wounding treatment where we used a razor blade to make a cut down the mid-vein of the leaf. The third treatment was a wounding treatment where we used a needle to poke holes on either side of the midvein covering most of the leaf. The fourth treatment is a liquid cytokinin dip where we dipped the entire leaf into a 250ppm cytokinin formulation. The fifth treatment is a liquid auxin dip where we dipped the entire leaf into a 500ppm auxin formulation.
Here is some information about what I have found out so far. I find that it is relatively easy to achieve 96% ... 100% strike rate with leaf cuttings of many Drosera species using absolutely no chemicals, but only substrate, light and water and a temperature appropriate for the species.
This is one example of 25 Drosera rotundifolia leaf cuttings with 100% strike rate:
Or another example of 49 Drosera intermedia "Carolina Giant" in one pot, from very small leaves taken early in the year:
To achieve very high strike rates I just have to provide artificial lighting (instead of natural light), controlled indoor temperature (instead of unstable outdoor temperature), high humidity (humidity dome) and take the leaf cuttings during the first half of the growing season (young leaves do better than old ones, early season leaves do better than those from the end of the growing season).
There are differences between species, i.e. D. filiformis leaf cuttings do not always work well for me. These five leaves of D. filiformis show a good strike rate for my standards (the small leaves beside D. filiformis are of a different species):
If I'd do further research, I'd try something with D. filiformis to achieve better and steady results.
Or perhaps with D. regia: I never could bring a single leaf cutting of D. regia to show new growth. Some people say, it's not possible to propagate D. regia with leaf cuttings, but others say it's easy (and they showed pictures).
For me improvements in leaf cuttings with D. regia would be much more exciting than improvements with leaf cuttings of species that are anyhow near 100% strike rate.
The purpose of this study is not to develop methods for inducing better strike rates, it is to increase the yield per leaf. It is also to determine whether wounding, cytokinin, and auxin have an effect on plantlet formation.If someone wants to donate enough filiformis or regia for us to do the experiment over again feel free I would love to try something that has a much less successful strike rate, however, we do not have the plants for that unfortunately. When our study concludes we will let you guys know exactly what we did and how we did it so that you can repeat it. Hopefully, this study will lead to some new methods for better propagation of many sundew taxa.
Just an update on the experiment. Most of the buds that have formed on all the surviving leaves have broken and are forming plantlets. One of the treatments has produced mounds of undifferentiated cells on most of the leaves. Some of these "buds" have differentiated into plantlets but many are just staying undifferentiated. An interesting note of that treatment is that the undifferentiated growth on the leaf blades have not produced that many plantlets, but the petioles have also formed a few undifferentiated growths that have now differentiated into plantlets.
Final update, this experiment has been completed and my partner and I are working on processing all the data. We will be publishing our study in the CPN and hopefully elsewhere as well. We have learned some very interesting things throughout this experiment and look forward to sharing it with you all. As a follow up study, over the summer and this coming fall I will be repeating this experiment using a difficult to root species, D. burmannii, and an "impossible" to root species, D. indica. We'll see how those turn out