EFFECT OF VARIOUS SUBSTRATES IN NON-CIRCULATING HYDROPONIC SYSTEMS AND SOIL MEDIA ON THE GROWTH OF Gynura procumbens

The limitations of conventional soil cultivation in producing medicinal plants emerge an interest in searching various alternative cultivation systems, one of which is the hydroponic system. This study aimed to investigate the effect of various substrates in non-circulating hydroponic systems and soil media on the growth of Gynura procumbens. Non-circulating hydroponic cultivation of Gynura procumbens was carried out using stem cuttings. The stem cuttings were transferred to each net pot containing substrates such as rockwool, tree fern fiber, and sawdust. The net pots were then placed in a tray comprising AB mix 6 ml/L of water. The lower 2-cm-portion of the net pots was immersed in a nutrient solution. Whereas in the conventional soil cultivation, the stem cuttings were transferred to the polybags containing soil media: compost (1: 1). After 28 days of cultivation, the plant growths were measured. The results showed that the use of various substrates in noncirculating hydroponics increased plant growth compared to conventional soil cultivation. Rockwool treatment obtained the highest number of leaves (14.833 ± 5.269 strands), number of roots (20.333 ± 6.121 stands), fresh weight (1.34 ± 0.511 g) and dry weight (0.088 ± 0.031 g).


Introduction
Gynura procumbens is a medicinal plant commonly found in tropical Asian countries such as Indonesia, Malaysia, China, Vietnam, and Thailand (Tan et al., 2016). The plant is known in Indonesia as "Sambung Nyawa" which means "prolongation of life". It is generally used in the treatment of fever, constipation, migraine,kidney disease, hypertension, cancer, and diabetes mellitus (Perry and Metzger, 1980). The plant has been reported to exhibit various pharmacological activities including antioxidant, antimicrobial, anti-inflammatory, anticancer,organ protective, antihyperglycemic, and antihyperlipidemic activities (Kaewseejan et al., 2015;Zheng et al., 2014;Shwter et al., 2014;Zahra et al., 2011;Hassan et al., 2010;Li et al., 2015).
Because of its great health benefits, G. procumbens has been widely used as raw materials for manufacturing drugs by the pharmaceutical industry. In addition, the plant is also used in various products in the cosmetic and food industries. The commercial importance of the plant as industrial raw materials has resulted in high demand for biomass (Tan et al., 2016). Overharvesting on the natural resources will cause loss of genetic diversity and habitat destruction, whereas conventional cultivation on soil media (open field) has many limitations because it is influenced by the climate, geographic or topographical conditions, and requires large areas of land and large water volume. In addition, in soil media, the availability and concentration of nutrients vary and are difficult to control (Beibel, 1964). Therefore, many efforts have been attempted to develop alternative methods for plant cultivation.
Hydroponic is one of the alternatives and potential methods in overcoming the limitations of conventional soil cultivation. Hydroponics is a Jurnal Biosains Vol. 6 No. 3 Desember 2020ISSN 2443-1230(cetak) DOI: https://doi.org/10.24114/jbio.v6i3.20101 ISSN 2460 method of plant cultivation using mineral nutrient solutions without soil as a planting medium (soilless cultivation) (Beibel, 1964). Hydroponic is a technology that can better control the availability of water and nutrients, increase crop productivity, and reduce pesticide use. The method is especially useful in areas where the soil or climate is not suitable for plant cultivation (Sheikh, 2006). The use of hydroponic methods has been proven to be more productive than conventional methods. In the greenhouse experiment, hydroponic cultivation has an average yield of 20-25% higher than conventional soil cultivation (Mugundhan et al., 2011). Mairapetyan et al. (2013) reported that the use of different types of hydroponic systems increased the productivity of the medicinal plants such as Mentha piperita L., Salvia officinalis L., Ocimum basilicum L., Bidens tripartita L., and Leonurus quinquelobatus Gilib.
One of the simplest types of hydroponic systems is non-circulating hydroponic. This system results in high productivity, cost-effectiveness, and efficient use of water or land. The system does not require aeration and circulation, so it does not need electricity and pumps. Several studies have shown the successful application of non-circulating hydroponic systems in growing various plants such as lettuce (Lactuca sativa L.), tomato (Lycopersicon esculentum Mill.), and cucumber (Cucumis sativus L.) (Kratky, 2005;Kratky et al., 2008;Mahlangu et al., 2016).
The hydroponics method of plant production requires a substrate to support the plant root system. The substrate can be in an organic form such as pine bark, peat, sawdust, and so on. They can also be in the form of inorganic minerals such as rockwool, sand, gravel, and others (Giurgiu et al., 2014). The use of various substrates such as rockwool, perlite, coconut coir, sawdust, pumice, and maize shredded stems have been reported to increase the growth of various plants (Jensen, 2010;Tzortzakis and Economakis, 2008;Klados and Tzortzakis, 2014). The selection of a suitable substrate is very important because it relates to the irrigation system (Giurgiu et al., 2014). The ability of the substrate to hold nutrient water will affect plant growth. However, there has been no type of substrate that can be used universally in various cultivation conditions, so it is very important to determine the type of substrate that ensure optimal and stable chemical-physical and nutritional conditions in growing a plant species in certain hydroponic systems (Maucieri et al., 2019).
The use of hydroponic systems due to the limitation of cultivation in soil media requires the appropriate substrate to optimize plant growth. Hence, it is needed to investigate and compare the plant growth in soil media and hydroponic systems using various substrates. To the best of our knowledge, the effect of various substrates in a hydroponic system and soil media on plant growth have been reported in many plants (Pelesco and Bentor, 2013;Mulyadi et al., 2013;Saroh et al., 2017), however, there have been no related studies regarding the growth of G. procumbens. Therefore, this study was conducted to determine the effect of various substrates in non-circulating hydroponic systems and soil media on the growth of G. procumbens

Materials and Methods
The research was conducted at the Integrated laboratory of UIN Sunan Ampel Surabaya. The research methods used a completely randomized design with four treatments and six replications. The treatments were non-circulating hydroponic cultivation using three substrates such as rockwool, sawdust, tree fern fiber, and conventional soil cultivation using soil media on polybags. The plant materials used were G. procumbens which were maintained in polybags with a mixture of soil media: organic fertilizers (1: 1). Trays with a size of 30 x 32.5x 12 cm were used as a growing system. The nutrients used in this study were AB mix 6 ml / L of water (Wibowo et al., 2018).
The non-circulating hydroponic system used in this study was a modification of the methods of Kratky (2004) and Pelesco and Bentor (2016). Cultivation of G. procumbens was carried out using stem cuttings. The stems of the plant were cut at a slope of 45 0 with a length of 5 cm from the tip of the plant. Apical buds and all the leaves were removed but two leaves were left. The remaining leaves were then cut in half crosswise. Stem cuttings were transferred to the net pots which have been filled with a substrate as much as 2/3 of the net pot volume. The substrates used were rockwool, tree fern fiber, and sawdust.
The net pots containing the stem cutting with each substrate were then placed in a tray (30 x 32.5x 12 cm) comprising AB mix 6 ml/L of water. The lower 2-cm-portion of the net pots was immersed in a nutrient solution (Figure 1). Whereas in the conventional soil cultivation (control treatment), the stem cuttings were transferred to the polybags containing soil media: compost (1: 1 were measured. The Data were statistically analyzed using SPSS version 24. Data were subjected to Duncan's Multiple Range Test and reported as means ± standard deviation(S.D.). A probability of p ≤ 0.05 was considered to be significant.

Result and Discussion
The result of plants yields in all treatments of various substrates in non-circulating hydroponic system had a normal and healthy leaf, stem, and root morphology similar to the control treatment in the soil medium (Figure 2). The success of growing plants using a non-circulating hydroponic system was also reported by Pelesco and Bentor (2016), in which the lettuce grown in a non-circulating hydroponic system produced healthy plants similar to the plants grown using conventional production systems. The advantage of using a non-circulating hydroponic system is that it does not require electricity and pumps. The lower portion of the net pot is immersed in a nutrient solution so that the plants are automatically watered because all the growing media (substrate) in the net pot becomes wet due to capillary events.
The result of statistical analysis demonstrated that the use of various substrates in the non-circulating hydroponic system and soil media affected the number of leaves, fresh and dry weights of plants, but did not affect the number of roots. The use of various substrates in non-circulating hydroponic cultivation increased all observed variables of plant growth compared to the soil media cultivation. Soil media obtained the lowest number of leaves (6.333 ± 1.366 strands), number of roots (15.500 ± 2.881 strands), fresh weight (0.596 ± 0.319 g) and dry weight (0.036 ± 0.014 g) ( Table 1). Gashgari et al. (2018) also reported that Cucumber and Armenian Cucumber grown using hydroponic systems produced higher growth rates than the conventional soil method. It indicated that the use of the hydroponic method was proven to be more productive than the conventional method. The increase in plant growth is probably due to the advantages of hydroponic over soil-based systems. The nutrients in soil media are heterogeneous, the availability of nutrients and nutrient concentrations varies and is difficult to control, in the contrast, hydroponic nutrient solutions are homogeneous and formulated to provide complete nutrition for plants and can easily be changed during experiments (Beibel, 1964;Pelesco and Bentor, 2016).
Our result showed that the use of various substrates in hydroponic systems produced different responses of plant growth. Previous studies of Nurzyński (2005), Majdi et al. (2012) and Arancon et al. (2015) also showed that there were significant differences in the use of various substrates on plant growth in the variables such as the number of leaves, plant height, and total yield. Substrate plays an important role in plant growth. The substrate is needed for supporting the plant root system and also serves as a place for exchanging gas between the roots and the atmosphere outside the root substrate, and providing water and nutrients for plants. The variety of raw materials in various substrates affects plant growth and development. Each type of substrate has different characteristics so that it has different abilities to support plant growth (Asaduzzaman et al., 2015). Nurzyński (2005) and Komosa et al. (2010) reported that although applied to the same nutrients, various substrates such as sand, rockwool, wood fiber, and peat showed significant differences in nutrient content.
The present study showed that rockwool produced the highest plant yield followed by sawdust and tree fern fiber, respectively. Rockwool resulted in the highest number of leaves (14.833 ± 5.269 strands), number of roots (20.333 ± 6.121 strands), fresh weight (1.34 ± 0.511 g) and and dry weight (0.088 ± 0.031 g) compared to sawdust and  fern substrates. Saroh et al. (2017) also reported that the use of rockwool resulted in higher lettuce (Lactuca sativa L) production than the sawdust substrate. Rockwool has several advantages such as not containing harmful microorganisms for plants, being porous, inert, and as noise and thermal insulation. Rockwool has a high porosity of 97.4%. A high porosity will provide good aeration and drainage. Moreover, it has a high water holding capacity. It can store water with a total volume of 374 ml / L (Urrestarazu et al., 2005). The water holding capacity of the substrate is very important because in this way plants can take nutrients and minerals from the solution at an optimal time (Giurgiu et al., 2014) The use of sawdust substrate resulted in the average number of leaves, the number of roots, fresh and dry weights that were 13.000 ± 2.449 strands, 19.167 ± 6.585 g, and 0.887 ± 0.524 g, and 0.062 ± 0.035 g, respectively, while the use of tree fern fiber substrate resulted in the average number of leaves, the number of roots, fresh and dry weights that were 10.667 ± 5.241, 18.667 ± 9.585, 0.684 ± 0.294 gram, and 0.049 ± 0.024 gram, respectively. The use of tree fern fiber produced the lowest plant growth compared to rockwool and sawdust. It is probably due to differences in the ability of these substrates to hold nutrient solution. Based on the study of Mulyadi et al. (2015), the fern substrate can hold nutrient water (16.54 ml/liter) lower than sawdust (24.88 ml/liter). However, on the contrary, the study of Mulyadi et al. (2015) showed that the use of sawdust substrate produced lower growth of tomato plants than the fern and other substrates. The high nutrient holding capacity of sawdust did not affect the growth of the tomato plant. It shows that various substrates have different effects on the growth of each plant, so the ideal substrate selection from various materials is very important to improve the productivity of each plant.

Conclusion
Our study indicated that the use of various substrates in non-circulating hydroponic systems and soil media affected the growth of G. procumbens. Non-circulating hydroponic systems using various substrates produced better growth of G. procumbens than conventional soil cultivation. Rockwool substrate produced the highest plant growth in all A B C D Jurnal Biosains Vol. 6 No. 3 Desember 2020 ISSN 2443-1230 (cetak) DOI: https://doi.org/10. 24114/jbio.v6i3.20101 ISSN 2460-6804 (online) observed variables such as the number of leaves (14.833 ± 5.269 strands), the number of roots (20.333 ± 6.121 strands), fresh weight (1.34 ± 0.511 g) and dry weight (0.088 ± 0.031 g). This method can be used as a simple alternative method for growing medicinal plants when there is limited land area, but it is also necessary to carry out further research to increase the plant production using various hydroponic systems.