ROOT INDUCTION OF PHALAENOPSIS AMABILIS WITH VARIOUS TYPES AND CONCENTRATION OF BANANA EXTRACT BY IN VITRO

Root induction is an important step in plant propagation by in vitro. Root stimulation can occur in the presence of the hormones auxin and gibberellins which can be obtained from other plants, one of which is bananas. The research aims to determine the effect of various types and concentrations of banana extract on Phalaenopsis amabilis root induction by in vitro. The research was conducted in Laboratory of Tissue Culture Alifa Agricultural Research Center (AARC), Medan, North Sumatera, from May until July 2020. The research used a Factorial Completely Randomized Design (CRD) with 2 factors, the first factor was the type of banana extract with 3 levels, consisting of Ambon, Raja, and Kepok. The second factor is the concentration of banana extract (C) with 4 levels, consisting of 50 g/l, 100 g/l, 150 g/l, 200 g/l. The results showed that the concentration of banana extract had significant effect on the number of roots, but various types of bananas and the interaction of the types of bananas and concentration banana extract had no significant effect on root induction.


INTRODUCTION
Phalaenopsis amabilis, family Orcidaceae, genus phalaenopsis. In Indonesia, this orchid is very well known and very popular so it has the potential to be developed, because it has a high commercial value with a unique flower shape such as a butterfly, long blooming time, and does not wilt easily. However, one of the problems is the limited availability of seeds, where generative propagation is difficult because the seeds do not have an endosperm as a food reserve and at an early age orchid plants have the potential to be infected with viruses. Effective and efficient cultivation is needed in the development of lunar orchids to increase their productivity [1].
Tissue culture is the most suitable technique for producing plant seeds in a short time with large numbers and the same characteristics as the parent. However, in vitro propagation techniques still have challenges in terms of slow growth of plantlets, low rates of multiplication, difficulty in rooting and somaclonal variation [2]. Isda and Siti [3] stated that the rooting process is one of the most important stages in the in vitro plant growth phase.
Stimulation of shoots and roots can occur due to cell division and the process of cell differentiation where this can occur with the help of the hormones auxin and gibberellins which can be obtained from banana extract. Kasutjianingati and Rudi [4] conducted a study on plantlets of dendrobium orchids with ambon banana extract treatment on the parameters of observing root length, plant height, number of roots produced a good effect. This is because, in Ambon banana there is a potassium (K) content for photosynthesis and respiration, as activating enzymes, phosphorus (P) and iron (Fe) play a role in plant metabolic processes, thus giving a positive influence on the growth of orchid plants [5].
The results of Utami et al research [6] also said that the administration of plantain extract in general had an effect on root induction and shoot growth of D. laianthera with 150 g/l plantain extract capable of inducing more root formation than other treatments. This is because banana extract contains thiamine which is useful in root meristems to accelerate cell division and also contains auxin and cytokinin compounds which are useful in cell enlargement, elongation and division.

METHODOLOGY
This research used a Factorial Completely Randomized Design (CRD) with 2 factors, the first factor was the type of banana extract with 3 levels, consisting of M1 = Ambon, M2 = Raja, and M3 = Kepok. The second factor is the concentration of banana extract (C) with 4 levels, consisting of C1 = 50 g/l, C2 = 100 g/l, C3 = 150 g/l, and C4 = 200 g/l.

Making banana extract
The bananas used consist of 3 types, namely Ambon, Raja and Kepok. Bananas are used in physiologically ripe conditions and good condition, that marked by the soft flesh. The bananas are mashed with a blender, then filtered and then put into a temporary cup [7].

Initiation Culture
Explants with good condition and have 2 leaves are ready for root induction. Root induction using full MS medium. Turn on the Bunsen lamp and remove the explant from the old bottle, after that it is placed in a petri dish and cleaned of remnants so that those that are still attached and the roots that have grown must be cut. The explants were then separated and planted on new media (treatment). Two moon orchid plants in 1 jump jar bottle [8].
The parameters observed included the percentage of live explants, percentage of explants forming roots, number of roots per explant and root length per explant.

Data analysis
Statistical analysis was done using Statistical Package for Social Sciences (SPSS) v 23.0. The analysis of variance (ANOVA) procedure for a factorial experiment was used to test for significant effect of treatments, followed by LSD test for comparisons of different means of different treatments.

Percentage of live explants (%)
The results of statistical analysis showed that MS media treated with various types and concentrations of banana extract and the interaction had an effect on the percentage of live explants of Phalaenopsis amabilis. The mean percentage of live explants can be seen in Table 1.  M1  100  100  100  100  100  M2  100  100  100  100  100  M3  100  100  100  100  100   Mean  100  100  100  100  100   Based on table 1, it can be seen that the percentage of live explants treated with various types and the concentration of banana extract reached 100% in all treatments. One of the characteristics live of the orchid plant is has the characteristics of a green color as shown in Figure 1.

Figure 1. Characteristics of live orchid plants
The use of basic media, namely MS, played an important role in the growth of explants because it contained high macro, micro, and vitamins, so that it has a good effect on the growth of Phalaenopsis amabilis plant. Pratama [9] states that the media used greatly influences the success in propagation of tissue culture. Complete macro and micro nutrients and vitamins are found in MS media which can be used in various plants.

Percentage of explants forming roots (%)
The results of statistical analysis showed that MS media treated with various types and concentrations of banana extract and the interaction between the two had an effect on the percentage of explants forming roots. The mean percentage of explants forming roots can be seen in table 2.  Note: Numbers that are not followed by letters in the same row and column show no significant difference in the LSD test at the 5% and 1%.
Based on table 2, it can be seen that the highest mean percentage of explants forming roots was found at the M1C1, M1C2 and M2C1 treatments was 80.56%, while the lowest mean was found at the M1C3 treatment was 41.67%. This is cause M1C3 media is contaminated with fungal, where media contaminated with fungal will make it difficult for explants to grow because explants that are injured due to initiation will be attacked through their tissues and the media is the right host for the growth and development of fungal so that root growth will be disrupted. In line with the statement of [10] that fungal contamination that occurs in the media has an effect on the growth of explants, as the day goes on, the growing media and explants will be covered by fungal microorganisms. A good substrate for the growth of fungal is the growth medium itself. The fungal will attack plant tissue through cuts caused by cutting during the initiation process.

Number of root per explant (unit)
The results of statistical analysis showed that MS media treated with various types of banana extract and treatment interactions had no significant effect on the number of roots per explant at the age of 1-6 weeks after planting (WAP), but the banana extract concentration treatment had a significant effect on the age of 6 WAP. The mean number of roots per explant can be seen in table 3.   Note: Numbers that are not followed by letters in the same row and column show no significant difference in the LSD test at the 5% and 1%.
Based on table 3, it can be seen that the concentration of banana extract significantly affected the number of roots per explant. The highest mean was found at the C1 treatment was 3.17 cm, while the lowest mean at the C4 treatment was 1.83 cm. Giving banana extract has a good effect on root growth, where the hormones gibberellins and auxins present in ripe bananas have an effect on stimulating root growth. Lestari and Ni Wayan [11] stated that the hormones auxin and gibberellins are found in ripe bananas. Auxins in tissue culture, in addition to stimulating cell elongation, callus formation, chlorophyll, root and shoot growth, and embryogenesis.  Figure 3 shows the equation = -0.0458x + 3.5 and the value of r = 0.926. It can be said that there was a decrease in the number of roots when the banana concentration was given higher. This is presumably due to the dense of banana extract so that excessive giving treatment of banana extract can cause explants to have disturbances in nutrient absorption and make it difficult for plant roots to get oxygen. The results of Bakrie's research [12] show that the use of good growing media, namely media that has cavities and roots must be able to easily get oxygen for its development.

Concentration of banana extract (g/l)
The results of statistical analysis showed that MS media treated with various types and concentrations of banana extract and the interaction between the two had no significant effect on root length per explant. The mean length of root per explant can be seen in table 4.  Note: Numbers that are not followed by letters in the same row and column show no significant difference in the LSD test at the 5% and 1%.
Based on table 4, it can be seen that the root length varied with the treatment of various types and concentrations of banana extract. The best banana type treatment was found at M2, was 0.33 cm, the best concentration treatment at C1 was 0.35 cm and the best interaction treatment at M3C3 was 0.43 cm.
The research results showed that in some culture media phenolic compounds were grown with phenolic compounds from the age of 3 WAP, which indicated by the appearance of a black color around the explants (Figure 3).

Figure 3. Phenolics in culture media
These phenolic compounds can affect plant growth and cause death because they are toxic to plants. According to [13], phenolics can grow in culture media will inhibit plant growth and sustainably the plant will die. In addition, [14] added that one of the causes of the formation of phenolic compounds is influenced by the plant species. Tropical plants have a higher phenolic content, one of which is orchids, which are oxidized when cells are injured or senescence occurs. As a result, plant tissue will turn brown to black and fail to grow.
The browning that occurs is caused by the activity of the oxidase enzyme which contains institutions and toxic which over time causes the death of plant.

CONCLUSION
The concentration of banana extract had significant effect on the number of roots, but various types of bananas and the interaction of the types of bananas and concentration banana extract had no significant effect on Phalaenopsis amabilis root induction. Ambon banana extract 50g/l can be used to increase the number of roots Phalaenopsis amabilis.