Vegetative multiplication of Taxus x media By Karl Beauchemin-Pratte and William Overbeek Plant propagation (PLNT 310)

The authors The authors are studying plant production at McGill University. Karl has The project been working in plant nursery for 5 The goal of the experiment was to years and William was raised on a cash asexually propagate Taxus x media with crop farm and both were intrigued by different lengths of stem cuttings and environmental conditions that included plant propagation. with and without bottom heat to find the Introduction ideal technique to propagate the plant. The Taxus is genus of conifer species stock plant was found on the Macdonald also known as yew. Taxus species naturally campus of McGill University and the cultivar grow in North America, Europe, Asia and was unknown. Two different propagation Australia (University of Kentucky, ND). treatments were used. The first one was the Usually, yews grow in the northern length of the cuttings. According to the hemisphere but can also grow in warmer literature, many different sizes can be climates. Most species prefer shade rooted. Since the plant takes time to root, conditions beneath the canopy of mountain bigger cuttings could possibly, reach salable trees (Farr, ND). Yews are gymnosperms in size before the smaller ones. Two sizes were which there are no real fruits but they tested (10 and 20 cm in length). When produce a structure that resembles and propagating some ornamental Taxus, function like a berry. heating cable treatment Yews are was found to be economically important increasing the time trees used as before rooting which is landscaping plants, to unusual (Eccher, ND). produce wood for Therefore, some furniture, and for the cuttings were grown famous Taxol which is with and without used to as a drug to bottom heat from fight cancer (University heating cables. 4 of Kentucky, ND). The different factors were compound is found in evaluated: the survival rate, the formation the inner bark in low concentrations. Taxol of callus, the formation of roots and the is expensive to extract and the plant is number of roots formed at the end of the destroyed in the process (Expósito, 2009). experiment. Information was gathered at Yews are normally propagated by the end because removing cuttings from the stem cuttings, but it takes time. Hormone medium could have damaged the newly powder is used to accelerate root formed roots. formation. Taxus canadensis can take up to 10 weeks to initiate root formation (Yeates Material and methods et al., 2005). The experiment took place in a mist frame located within the Raymond greenhouse. Small cuttings of roughly 10 cm were compared to cuttings of 20 cm. For each length of cuttings, one group was provided with bottom heat whereas the other group did not receive supplemental heat. All the cuttings received the same conditions except the two mentioned above. They had the same temperature and they were placed in a mist frame because cutting spent several weeks in there and we wanted to avoid desiccation. The cuttings were taken from upright juvenile shoots Results to keep the growing habit. All the cuttings survived and Before sticking, all the cuttings produced callus.

were dipped into a rooting hormone Table 1. Summary of results. powder composed of IBA with a concentration of 10,000 ppm as this has Cutting Bottom Root Root been shown to greatly reduce the length heating formed number amount of time necessary for root (cm) development. The medium for the trial 10 Yes 2 2 roots was 1 part Fafard G10 and 1 part Perlite 1 root (1 G10 : 1 Perlite) as recommended by 10 No 10 7 X 1 root 2 roots Yeates et al (2005). 4 containers were 3 roots used and divided into 2 (2 containers 5 roots with bottom heat and 2 without). The 2 20 Yes 0 0 different lengths were randomly 20 No 1 1 root assigned in these containers. 3 The 10 cm cuttings outperformed the 20 cm replicates of each treatment were cuttings. 12/66 10 cm cuttings produced prepared. Therefore, 12 blocks were roots, and there were more roots in used. Each bloc had 11 cuttings for a average (average 1.6/cutting) whereas only total of 132 cuttings. The cuttings were 1/66 of the 20 cm cuttings produced roots planted on January 27 and were with only 1 root in the time frame provided. harvested on April 4, 2017. The cuttings Bottom heating slowed down root were cultivated for a total of 67 days. formation. Ten 10 cm cuttings and only one 20 cm cutting produced roots with no bottom heating whereas two cuttings produced roots in the presence of bottom heat. The only 20 cm cutting that produced a root did not receive bottom heating. root formation. On the other hand, auxin produced by the new shoot may promote root formation. Therefore, it would be interesting to see the effect of removing the new shoots.

Discussion and recommendations The experiment did not last long enough to have decisive results. According to Henry et al. ( 1992), longer cuttings in conifer should result in a greater root count and length but the opposite was found in our trial. Unrooted cuttings were all still healthy so root formation would likely have Acknowledgement eventually occurred. Nevertheless, in the We would like to thanks Dr. Danielle 10-week time frame provided, shorter Donnelly for helping us in designing a cuttings produced more roots and each proper experimental design. We would also rooted cutting had more roots on average. like thanks Mme. Jeanne Page from the Bottom heating did seem to slow team of gardeners at Macdonald campus root formation. This confirms what Eccher who generously allowed us to take cuttings (ND) found in his experiment. It may be from a Taxus on the campus. counterintuitive but propagators working with yew should avoid bottom heating. Literature Cited According to the present experiment, the Eccher, T. ND. Response of cuttings of 16 best cuttings were 10 cm in length and Taxus cultivars to rooting treatments. bottom heating was not beneficial. Available at: The experiment was not ideal for http://www.actahort.org/members/showp many reasons. First, the experiment was df?session=24177 (Accessed: 18 January too short to achieve definitive results. 2017). Increasing the time would have helped longer cuttings to produce roots. Also Expósito O., M. Bonfill, E. Moyano, M. during sticking, we did not dig holes before Onrubia, M.H. Mirajalili, R.M. Cusidó and J. inserting the cuttings into the medium. Palazón. 2009. Biotechnological production Therefore, it is possible that some rooting of taxol and related taxoids: Current state powder was removed from the wound and and prospects. Anti-cancer agents in the hormone may have been less effective. During the experiment, lateral buds formed medicinal chemistry., 9(1):109–21. shoot. This factor may have influenced the Farr, K. ND. Genus-level approach to Taxus results since new shoots produce auxin. In a species. Available at: future experiment, it would be interesting https://cites.org/sites/default/files/ndf_ma to see the effect of these new shoots on terial/WG1-CS6.pdf (Accessed: 18 January root development. Since the plant is using its energy to produce shoots, it may inhibit 2017). Henry, P.H., F.A. Blazich and L.E. Hinesley. 1992. Vegetative propagation of eastern red cedar by stem cuttings. HortScience. 27(12):1272-1274.

University of Kentucky. No date. Taxaceae. Available at: http://dept.ca.uky.edu/PLS320/Lecture12Ta xaceae-SH.pdf (Accessed: 18 January 2017).

Yeates L.D., R.F. Smith, S.I. Cameron, and J. Letourneau. 2005. Recommended procedures for rooting ground hemlock (Taxus canadensis) cuttings. Available at: http://www.cfs.nrcan.gc.ca/pubwarehouse/ pdfs/25681.pdf (Accessed: 18 January 2017).