Hydroponic method for plants

Abstract

The present disclosure provides a hydroponic method for plants. Provided is a hydroponic method for plants comprising: (1) reducing the root system amount of the plant; and (2) cultivating, by means of hydroponics, the plant after the root system amount has been reduced.

Description

Hydroponic cultivation method for plants

[0001] The present disclosure relates to a method for hydroponic cultivation of plants.

[0002] In crop cultivation, fertilizer and water are used to ensure high production, but improving the efficiency of nutrient and water use in plant cultivation is one of the important issues from the perspective of effective resource utilization and preventing environmental pollution due to fertilizer runoff.

[0003] There are two types of plant cultivation: soil culture, in which plants are grown in soil, and hydroponics, in which plants are supplied with nutrients and water using a culture solution without using soil. In hydroponics, efforts have been made to improve yield and quality by improving varieties, environmental control, culture media, culture solutions, etc. (Non-Patent Documents 1 and 2).

[0004] The roles of the underground parts of plants, i.e., the root system, include supporting the above-ground parts, absorbing nutrients and water, and supplying growth regulators to the above-ground parts (Non-Patent Document 3). In soil cultivation, where plants are grown using soil, nutrient and water shortages easily occur, and plants form relatively large root systems to maintain growth.

[0005] Ota et al., 1991, "Effects of nutrient solution concentration and salt treatment on fruit quality and yield of hydroponically grown cherry tomatoes," Journal of the Japanese Society of Horticultural Science, Vol. 60 (1991-1992), No. 1; Ono et al., 1998, "Effects of supplemental lighting on growth and yield of hydroponically grown rice," Vol. 36, No. 3, pp. 151-157; Sakamoto, 1998, "The significance of root research in hydroponics," Root Research, 7, 113-116.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a method for hydroponics cultivation of plants.

[0007] One aspect of the present disclosure is a method for hydroponically cultivating a plant, the method comprising: (1) reducing the root mass of the plant; and (2) cultivating the plant in a hydroponics culture after reducing the root mass.

[0008] According to the present disclosure, a method for hydroponics of plants can be provided.

[0009] Figure 1 shows the dry weight of the above-ground parts of the root-excision treated group and the untreated group on the 26th day after transplanting. Figure 2 shows the dry weight of the underground parts of the root-excision treated group and the untreated group on the 26th day after transplanting. Figure 3 shows the above-ground dry weight / underground dry weight ratio of the root-excision treated group and the untreated group on the 26th day after transplanting.

[0010] In contrast to soil culture, in hydroponic cultivation, plants often have easy access to constant nutrient water, which can lead to the formation of root systems in excess of the amount required to maintain growth. Therefore, by appropriately reducing the amount of underground tissue, it is possible to reduce the amount of nutrient water required to form and maintain roots.

[0011] For these reasons, it is thought that in hydroponics, reducing the amount of underground parts and improving the balance between above-ground and below-ground parts of crops would enable efficient cultivation with less nutrient use while maintaining the productivity of the above-ground parts. However, to date, hydroponics technology has not been studied from this perspective.

[0012] Non-limiting embodiments of the present disclosure will be described below. The present disclosure is not limited to the examples in the following embodiments.

[0013] In an embodiment, a method for hydroponically cultivating a plant is provided, the method comprising: (1) reducing the root mass of the plant; and (2) cultivating the plant in hydroponics after reducing the root mass.

[0014] In an embodiment, the type of plant is not particularly limited as long as it can be grown hydroponically at any stage based on the knowledge of a person skilled in the art, and may include, but is not limited to, plants of the families Malvaceae, Rubiaceae, Brassicaceae, Poaceae, Cucurbitaceae, Asteraceae, Moraceae, Pesamiaceae, Araceae, Umbelliferae, Solanaceae, Papayaceae, Rosaceae, Amaryllidaceae, Leguminosae, Rutaceae, Oleaceae, Amaranthaceae, and Liliaceae. Brassicaceae, Asteraceae, Apiaceae, Solanaceae, Rosaceae, Amaranthaceae, and Fabaceae are particularly preferred. More specific examples of plants according to the embodiment include kiwifruit (Actinidia deliciosa), onion (Allium cepa), leek (Allium fistulosum), garlic (Allium sativum), celery (Apium graveolens var. dulce), Arabidopsis (Arabidopsis thaliana), peanut (Arachis hypogaea), beet (Beta vulgaris subsp. Vulgaris), cauliflower (Brassica oleracea var. botrytis), cabbage (Brassica oleracea var. capitata), broccoli (Brassica oleracea var. italica), rapeseed (Brassica rapa), bok choy (Brassica rapa var. chinensis), mizuna (Brassica rapa var. nipposinica), komatsuna (Brassica rapa var. perviridis), and turnip (Brassica rapa var.rapa), tea plant (Camellia sinensis), bell pepper (Capsicum annuum), paprika (Capsicum annuum), safflower (Carthamus tinctorius), lime (Citrus aurantifolia), lemon (Citrus limon), orange (Citrus sinensis), grapefruit (Citrus x paradisi), coconut palm (Cocos nucifera), coffee tree (Coffea arabica), taro (Colocasia esculenta), mitsuba (Cryptotaenia japonica), cucumber (Cucumis sativus), pumpkin (Cucurbita spp.), carrot (Daucus carota subsp. sativus), persimmon (Diospyros kaki), oil palm (Elaeis spp.), buckwheat (Fagopyrum esculentum), arugula (Eruca vesicaria), fig (Ficus carica), strawberry (Fragaria x ananassa), garland chrysanthemum (Glebionis coronaria), soybean (Glycine max), sunflower (Helianthus annuus), barley (Hordeum vulgare), sweet potato (Ipomoea batatas), morning glory (Ipomoea nil), lettuce (Lactuca sativa), lentil (Lens culinaris), apple (Malus domestica), peppermint (Mentha x piperita), banana (Musa spp.), watercress (Nasturtium officinale), tobacco (Nicotiana tabacum), basil (Ocimum basilicum), olive (Olea europaea), rice (Oryza sativa), shiso (Perilla frutescens var.crispa), avocado (Persea americana), parsley (Petroselinum crispum), kidney bean (Phaseolus vulgaris), pepper (Piper nigrum), pea (Pisum sativum), pear (Pyrus pyrifolia), radish (Raphanus sativus var. hortensis), rose (Rosa spp.), rosemary (Rosmarinus officinalis), sugarcane (Saccharum officinarum), tomato (Solanum lycopersicum), eggplant (Solanum melongena), potato (Solanum tuberosum), sorghum (Sorghum bicolor), cocoa (Theobroma cacao), thyme (Thymus vulgaris), wheat (Triticum aestivum), blueberry (Vaccinium spp.), adzuki bean (Vigna angularis), grape (Vitis spp.), corn (Zea Examples of suitable vegetables include, but are not limited to, Zingiber mays, Zingiber mioga, Zingiber officinale, and related species. Among these, herbaceous plants are preferred, and those that are not root vegetables are preferred. Among these, Arabidopsis thaliana, tomato, cucumber, strawberry, lettuce, pepper, green onion, mitsuba, Japanese radish (especially those cultivated as sprouts), and shiso are particularly preferred.

[0015] As commonly understood by those skilled in the art, hydroponics in this disclosure refers to a method of cultivating plants (or crops) that are normally rooted in soil using an aqueous nutrient solution (culture solution) containing nutrients without using soil. This includes at least hydroponics, in which crops are cultivated by exposing the roots to liquid without using a solid culture medium, and solid culture, in which crops are cultivated using a solid culture medium that acts as a substitute for soil, supports the roots, and is impregnated with liquid, and a culture solution. In the hydroponics embodiments, cultivation using solid culture is preferably performed using solid culture. Solid culture media known to those skilled in the art, such as urethane culture media primarily made of foamed polyurethane sponge, rock wool culture media, and coconut shell culture media, can be used. Solid culture may also be gravel culture, which uses gravel such as pumice as a culture medium, or independent pot culture, which uses nonwoven fabric as a culture medium.

[0016] The nutrient solution used in the hydroponic culture of the present invention can be a nutrient solution containing salts such as potassium nitrate, calcium nitrate, ammonium nitrate, magnesium nitrate, ammonium sulfate, ammonium chloride, urea, potassium sulfate, magnesium sulfate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, potassium chloride, calcium chloride, ferrous sulfate, boric acid, manganese sulfate, zinc sulfate, copper sulfate, and sodium molybdate, as well as chelating agents (e.g., EDTA). The composition and concentration of these nutrient solution components can be adjusted appropriately depending on the species or variety of the plant being cultivated, the cultivation conditions, and the purpose of the cultivation. Watering with such a nutrient solution provides the nutrients and moisture necessary for plant growth. The hydroponic culture of the present invention can be performed using a cultivation device known to those skilled in the art, including a cultivation bed, a nutrient solution tank, a solution supply pump, and water supply and drainage pipes. The nutrient solution can be supplied to the plants by either a circulating or non-circulating supply method. The nutrient solution can be supplied by placing plants, optionally fixed in a solid medium such as urethane medium, in a cultivation bed that is constantly irrigated. The nutrient solution culture of the embodiment can be accompanied by irradiation with natural or non-natural light.

[0017] In one embodiment, a hydroponic cultivation method for a plant includes (1) reducing the mass of the root system of the plant. In the present disclosure, the root system of a plant generally refers to the underground organs of the plant, including at least the taproot, lateral roots, and fibrous roots. Here, the term "underground" also refers to "below the water surface" in plants grown submerged in liquid. As will be understood by those skilled in the art, a root system is an organ whose functions include supporting the aboveground part, absorbing nutrients and water, and supplying growth regulators to the aboveground part.

[0018] In the present disclosure, the "quantity" of a root system refers to the quantity expressed by weight (wet weight or dry weight), and particularly for taprooted plants, it can also be expressed by the length of the taproot. In embodiments, reducing the root system mass of a plant can mean, for example, reducing the root system mass of the plant to 10-90%, 20-70%, or 30-50% of the root system mass of the plant individual prior to the process. Reducing the root system mass of a plant can be achieved by any procedure that artificially reduces the root system mass, such as physical treatments such as cutting or heat treatment, chemical treatment, or other methods, but physical treatment is preferred. When physical treatments are used, the root system mass can be reduced by, for example, cutting the roots midway with scissors or a blade, or by burning the roots from the tip with a gas burner or heated metal. Reducing the root system mass of a plant in this manner improves the balance between the aboveground and underground parts of the plant, enabling improved nutrient utilization efficiency in hydroponic cultivation. Cutting the taproot midway also removes lateral roots, fibrous roots, and other roots associated with the taproot, making this method preferable.

[0019] That is, in the hydroponic cultivation method for plants according to the embodiment, reducing the root mass of a plant can be achieved by cutting the roots of the plant to shorten the roots. For example, when cultivating using a solid medium such as a urethane medium, shortening the roots can be achieved by cutting the remaining roots, leaving a certain length of the taproot and other associated roots extending into or below the solid medium. In this case, the length of the taproot to be left can be at least 1 cm, 3 cm, 5 cm, 10 cm, or more, for example, 1 to 5 cm. The amount of roots to be left can also be specified relative to the total amount of the root system or the amount (weight or height) of the above-ground portion. In this case, the amount of roots to be left can be at least 5%, 10%, 20%, 30%, 40%, or 50% of the total root system or above-ground portion before root mass reduction. The amount of roots to be left can be less than 90%, 80%, 70%, 60%, or 50%, or at most 50% of the total root system or above-ground portion before root mass reduction. Preferably, the amount of above ground parts of the plant is not reduced when the amount of the root system is reduced.

[0020] The method of the embodiment includes (2) cultivating the plant after the root mass has been reduced in a nutrient solution. This step can be performed to promote growth of the plant, particularly the above-ground parts, after the root mass has been reduced. At this time, since the roots of the plant have been removed, the presence of excess roots is eliminated, allowing for efficient nutrient utilization.

[0021] In the embodiment of the hydroponic cultivation method for plants, the set of steps (1) and (2) may be performed once, twice, three times, four times, or five or more times. The number of sets of steps (1) and (2) and the interval between sets may be appropriately adjusted depending on the species or variety of the plant to be cultivated, the cultivation conditions, the purpose of cultivation, etc.

[0022] For example, in the embodiment of the plant hydroponic culture method, when the set of steps (1) and (2) is performed two or more times, the subsequent set can be performed after the root system volume of the plant is restored by the solution culture in step (2) and becomes closer to the root system volume immediately before step (1) than to the root system volume immediately after step (1).By performing the subsequent set after the root system volume immediately after step (1) in the preceding set becomes closer to the root system volume immediately before step (1) than to the root system volume immediately after step (1) in the preceding set, the root system volume can be maintained so as not to exceed the amount necessary for the growth of the above-ground part.

[0023] Specific embodiments will be described in more detail below with reference to examples, but the embodiments of the present invention are not limited to the specific plant species or specific experimental conditions described below.

[0024] Arabidopsis seeds were sown in a solid urethane medium and grown in a culture solution. Thirty days after seedling growth, the plants were transplanted together with the urethane medium into a constantly irrigated cultivation bed and grown in a solid medium. Standard culture solutions known to those skilled in the art were used.

[0025] On the 14th and 21st days after transplantation, the root systems were excised, leaving up to 3 cm below the urethane medium (hereinafter referred to as excision treatment).

[0026] After harvesting the plants 26 days after transplanting, the dry weights of the above-ground and below-ground parts of the root-excision and non-root-excision groups were measured, and the ratio of above-ground dry weight to below-ground dry weight was calculated. Student's t-test was used to test for significance between groups.

[0027] As a result, no significant difference was found in aboveground dry weight between the groups (Fig. 1). On the other hand, belowground dry weight was significantly lower in the root-removed group (Fig. 2), and the aboveground / underground dry weight ratio (Fig. 3) was significantly higher in the root-removed group.

[0028] These experiments demonstrated that in hydroponic systems, the amount of underground tissue in plants exceeds the amount of aboveground tissue, and that artificially reducing the amount of underground tissue can reduce the amount of nutrients required to form and maintain the underground tissue while maintaining the amount of aboveground tissue growth. These results demonstrate that improving the balance between aboveground and underground tissue in plants can improve the efficiency of nutrient utilization in hydroponic culture.

[0029] The present disclosure includes the following embodiments. (Item 1) A method for hydroponics of a plant, comprising: (1) reducing the root mass of the plant; and (2) cultivating the plant in a hydroponics culture after the root mass has been reduced. (Item 2) The method according to Item 1, wherein reducing the root mass of the plant is carried out by cutting the roots of the plant to shorten the roots. (Item 3) The method according to Item 1 or 2, wherein a set of steps (1) and (2) is carried out two or more times. (Item 4) The method according to any one of Items 1 to 3, wherein the subsequent set is carried out after the root mass of the plant has recovered through hydroponics and is closer to the root mass immediately before step (1) than to the root mass immediately after step (1) is carried out.

[0030] Although the present disclosure has been described with reference to the above several embodiments, the present disclosure is not limited to the above several embodiments. Various changes can be made to the configuration and details of the present invention within the scope of the present disclosure.

Claims

1. A method for hydroponically cultivating a plant, the method comprising: (1) reducing the root mass of the plant; and (2) cultivating the plant in a hydroponics solution after reducing the root mass.

2. The method according to claim 1, wherein reducing the root mass of the plant is carried out by cutting the roots of the plant to shorten the roots.

3. The method according to claim 1 or 2, wherein the set of steps (1) and (2) is carried out two or more times.

4. The method according to claim 3, wherein the subsequent setting is carried out after the root volume of the plant is restored by the hydroponic culture and becomes closer to the root volume immediately before step (1) than to the root volume immediately after step (1).

Images