Graduate research rules a go-to hormone for cycad propagation ineffective
The newly published thesis research of 91快播 Master of Environmental Science graduate Benjamin Deloso now adds to the body of knowledge about asexual propagation of the most endangered plant group in the world, cycads. His work was part of a set of UOG studies, all focused on improving the asexual propagation of cycads, , one of the oldest horticultural journals in the United States.
With the assistance of his professors, Deloso designed a set of experiments to examine the speed of adventitious rooting in 鈥減ups,鈥 external stems produced from parent plants. He used two species of Zamia, a group of cycads native to the New World. These model species were chosen for two replicated rooting studies utilizing indole-3-butyric acid (IBA), the most common rooting hormone used in asexual propagation protocols.
Cycad horticulturists typically employ the use of IBA in asexual propagation, and previous research utilizing IBA on angiosperms, or flowering plants, suggests that an ideal concentration of IBA exists for cycads. However, the efficacy of IBA on cycads was unknown. 鈥淒o cycads actually benefit from IBA?鈥 wondered Deloso, lead author of the study.
鈥淭hat was one of our objectives,鈥 he said. 鈥淪o we included a range of IBA that was 10 times higher than the dose that is most commonly used in commercial horticultural operations to see if there would be a negative response.鈥
In contrast to all expectations, the cycad stem cuttings did not appear to benefit from any of the IBA doses used as the control groups performed just as well as the other treatment groups.
鈥淭he results were surprising. Our research illuminates how much is still unknown about cycad biology and highlights how different they are from other groups of plants,鈥 Deloso said.
This knowledge could benefit cycad conservation in countries where commercial IBA products are difficult to obtain.
Previous asexual propagation studies utilizing cycad stem cuttings did not involve the use of a range of IBA nor did they include a control group.
鈥淎fter reviewing the scientific literature, it was clear that previous studies did not employ typical horticultural protocols,鈥 said Frank Camacho, UOG associate professor of biology and one of the authors of the study.
This makes Deloso鈥檚 study the first of its kind in the cycad horticulture literature.
While IBA may not influence successful propagation of Zamia cycads, Deloso鈥檚 study notes that additional studies are needed to determine its effectiveness on the other 300-plus cycad species, in particular those that are threatened, such as the endemic Cycas micronesica of Guam, Rota, Yap, and Palau. He also noted other factors found in his previous research that have proven to assist the propagation process.
鈥淥耻谤 previous research has highlighted the relative ease of asexually propagating cycad plants. High survivability is achieved when hygienic conditions are adhered to, cuttings are obtained from healthy plants, the cut surfaces are covered with a sealant to prevent desiccation, the growing medium exhibits adequate aeration and drainage capacity, and underwatering during the propagation phase is followed,鈥 Deloso said.
Deloso credits his decision to publish his research to the guidance of his academic advisors and the encouraging atmosphere at the 91快播.
鈥淚 understood the importance of publishing original research, which makes it available to the international community,鈥 Deloso said. 鈥淭he guidance of my academic advisors at UOG helped me realize how important this endeavor is. I am thankful to the University of Guam for providing the opportunity to study this unique plant group.鈥
Anders Lindstr枚m of the Nong Nooch Tropical Botanical Garden, another author of the study, said he is encouraged by the results of the study, saying, 鈥淐ontinued improvements in cycad horticulture are of great importance to the conservation of this unique plant group. We 鈥 look forward to collaborating more with the 91快播 in the future.鈥
The 91快播 continues to publish original research on cycads.