Haworthiopsis limifolia, a cactus native to South Africa, is one of the herbaceous ornamental plants belonging to the Asphodelaceae family. This succulent perennial plant is known for its medicinal properties, including antibacterial and antifungal properties. The production and cultivation of this plant are traditionally associated with low yield and time consumption, which do not meet any needs of the market, and the producer faces problems with mass production. To solve these problems, new propagation methods, such as tissue culture, are used. The objectives of this study were to introduce a novel protocol for disinfecting Hawthorn for in vitro tissue culture and investigate the effects of different levels of growth regulators, including BAP (benzyl amino purine) and IBA (indole butyric acid), on the micropropagation of this plant. The results showed that 1.5% sodium hypochlorite solution for 10 minutes was the best treatment for the disinfection of the isolated cultures. In addition, our results indicated that the highest number of succulents (10) belonged to the treatment of 1.5 mg /L BAP. According to the mean comparison, the best treatment for rooting was 1.5 mg/L of IBA. The 1.5 mg/l concentration of BAP led to the maximum number of succulents. Moreover, BAP had a more significant effect than IBA on cacti's rooting, shooting, and suckering.
Introduction
The Haworthia limifolia, with the scientific name Haworthia limifolia, is an ornamental, herbaceous, and perennial plant from the Asphodelaceae family and tends to fall under the category of succulent cactus plants. This particular plant originates from South Africa and is commonly grown for decorative purposes. It is also known for its medicinal properties, which include antibacterial and antifungal benefits. Haworthia limifolia is a highly prized plant, sought after for its unique and stunning appearance, featuring two distinct colors, and it is often considered an ornamental plant. This plant's compact size allows for easy cultivation in a small pot or a lovely terrarium alongside other decorative succulents. In addition, in the past years, Haworthia limifolia, like aloe vera plants, has been widely considered in traditional medicine among the natives of the region. Traditionally, the yield and breeding of this plant are low and time-consuming, which fails to meet market demands. As a result, the producer encounters difficulties in mass production. Modern methods, like tissue culture, are used to solve this problem. The success rate of micropropagation depends on multiple factors, including explant type, nutrients, plant growth regulators, additives, temperature, light intensity, and duration.
Materials and Methods
The offshoots surrounding the plants were removed, and the roots were gently separated without causing any harm to the plant. Next, the leaves and meristem were placed in a net and washed under running water for one hour. To disinfect the samples before growing them in the plant culture media, 2.5 ml of 20% Tween 20 were added to 100 ml of water after washing with running water for one hour. Then, the samples were soaked in the solution of Mancozeb fungicide (2 grams per 100 ml) and remained in this solution for 20 minutes. Following the disinfection process, small pieces of leaves containing meristems were placed on an MS culture medium (pH=5.8) with 30 grams of sucrose and 7 grams per liter of agar for 14 days. The samples were then regularly subcultured. Different concentrations (0, 1, 1.5, 2, and 4 mg/L) of IBA (indole butyric acid) and BAP (benzyl amino purine) hormones were applied to produce shoots, roots, and offshoots. After four weeks, the desired traits were measured.
Results and Discussion
Based on our results, the most effective way to disinfect isolated cultures is to treat them with a 1.5% sodium hypochlorite solution for 10 minutes. Variance analysis showed that the effect of BAP concentration on the number of Haworthia leaves was significant at the five percent level. The variance analysis indicates that the concentration of BAP had a significant impact on the number of leaves, the length of the longest leaf, and overall plant height. However, the number of roots in Haworthia limifolia was only significantly affected by the concentration of IBA hormone and the type of culture medium used, with no noticeable impact from the interaction of these factors. Our results revealed that the treatment of 1.5 mg/L BAP resulted in the highest number of stems (10) in Haworthia tissue cultures, and the most effective treatment for rooting was IBA at a concentration of 1.5 mg/L according to mean comparison results. In the stem formation stage, the tallest seedlings were observed in the treatment with 1 mg/L BAP hormone, indicating a 45.5% increase compared to the control treatment in contrast, the treatment with the highest concentration (4 mg/L) of BAP resulted in the shortest seedlings, with a decrease of 42.2% in plant height compared to the control treatment. Overall, as the concentration of BAP hormone increased, the height of Haworthia seedlings decreased. In addition, using IBA hormone at a 0.5 mg/L concentration resulted in a 17.8% reduction in seedling height. The best results for offshoot growth were achieved by using 1.5 mg/liter BAP in the plant culture medium.
Conclusion
The purpose of this study was to discover a way to disinfect Haworthia for in vitro tissue culture and explore the impact of various levels of growth regulators, such as BAP and IBA, on the plant's micropropagation. The findings revealed that BAP had a greater influence than IBA on the production of shoots, roots, and offshoots in Haworthia explants.