Optimizing Thidiazuron and Carrot Extract for Micropropagation and Phytochemical Profiling of Dendrobium macrophyllum A.Rich

In the humid forests of Indonesia and neighboring countries, a unique orchid known as Dendrobium macrophyllum clings to the branches of trees, its pale green flowers and fuzzy texture marking it as a distinct part of the local ecosystem. Like many wild orchids, this species faces a precarious future; its natural seeds are so tiny and dependent on specific soil fungi that they rarely sprout on their own, and the demand for these plants in traditional medicine and horticulture has led to overharvesting. To save such species from disappearing, scientists turn to a method called micropropagation, which is essentially a way to grow thousands of identical plants in a laboratory setting without relying on seeds. This process involves taking a small piece of a plant, such as a stem, and placing it in a nutrient-rich gel that encourages it to grow new roots, leaves, and shoots. The success of this technique depends heavily on the recipe of the gel, specifically the balance of growth regulators—chemicals that tell the plant cells when to divide and when to form new structures. While scientists have long used synthetic chemicals to guide this growth, there is growing interest in mixing these with natural extracts from common plants, hoping to find a more effective and perhaps gentler way to multiply endangered species.

Researchers at Sebelas Maret University in Indonesia set out to find the perfect recipe for multiplying Dendrobium macrophyllum by testing a specific combination of a synthetic growth regulator called thidiazuron and a natural extract made from carrots. They grew stem slices of the orchid in glass jars containing a nutrient gel, varying the amounts of the two ingredients to see which mix produced the healthiest plants. The team discovered that a specific combination worked significantly better than the others: a concentration of 1.5 parts per million of thidiazuron mixed with 20 milliliters of carrot extract per liter of gel. This particular mixture acted as a powerful catalyst for growth. Compared to plants grown without any additives, those in the optimal mixture developed 177 percent more roots, 69.5 percent more leaves, and 90.68 percent more new shoots. The carrot extract played a crucial role in speeding up the process, helping the new shoots appear about nine days faster than in other treatments, while the thidiazuron drove the overall increase in the number of plant parts.

The researchers did not stop at counting leaves and roots; they also looked closely at the internal structure of the plants to understand how these chemicals changed the orchid's biology. Using microscopes, they measured the thickness of the leaf and root tissues, finding that the balance of chemicals influenced how the cells packed together. For instance, the leaves grown with certain treatments had thicker internal layers, which can help the plant manage water and nutrients more effectively. The study also revealed that the chemical makeup of the plants grown in the lab differed from those growing in the wild. By analyzing the plant tissues with a machine that separates and identifies chemical compounds, the team found that the laboratory-grown plants were rich in specific fatty acids, particularly one called octadecanoic acid, which made up more than half of the detectable compounds. In contrast, the wild mother plants had a more varied chemical profile, including different types of esters and terpenes that are often associated with medicinal properties.

These findings suggest that by carefully tuning the growth environment, scientists can not only multiply endangered orchids more efficiently but also potentially influence the production of valuable chemical compounds within them. The study confirms that combining a synthetic growth regulator with a natural carrot extract creates a synergistic effect, where the two work together to stimulate growth more effectively than either could alone. While the wild plants produced a wider variety of chemical compounds, the laboratory-grown plants showed a significant boost in specific fatty acids that help plants respond to stress. This research provides a concrete, optimized method for preserving Dendrobium macrophyllum, offering a reliable way to increase its population for conservation and future study without relying on the slow and uncertain process of natural seed germination.