Plant growing device

Abstract

The present invention relates to a plant growing device for germinating plant seeds in a microgravity space environment and / or in a clinostat or in a normal gravity space environment, the device being provided with a passive water and / or nutrient supply system. The plant growing device comprises a germination receptacle (2) made of a non-transparent material provided with a liquid inlet connection element (8), a cover element connected to the germination receptacle (2) via an intermediate piece (10), a high absorption capacity absorbent mat (7) arranged on the lower surface of the germination receptacle (2), a germination module arranged in the germination receptacle (2) between the absorbent mat (7) and the cover element.

Description

[0001] Plant growing device

[0002] The present invention relates to a plant growing device for germinating plant seeds in a microgravity space environment and / or clinostat or in a normal gravity space environment provided with a passive water and nutrient supply system.

[0003] The main obstacle in growing plants in spacecrafts and space bases are water and nutrient absorption difficulties due to microgravity or hypogravity.

[0004] For the ISS station, the NASA has developed two systems for plant experiments. The APH (Advanced Plant Habitat) system is equipped with sensors and is based on the so-called active nutrient and water supply method. The system is also provided with a pump unit with porous tubes permeable to water under pressure that can be embedded in the root region and the growing medium. The VEGGIE system basically enables only the lighting of plants with a smart system provided with a six-channel LED lighting device (Phytofly, OSRAM). The VEGGIE system accommodates different plant growth units with passive water and nutrient supply, such as PILLOW, PONDS (Passive Orbital Nutrient Delivery System), APEX-PGU (Plant Growing Unit) and XROOTS (eXposed Root On-Orbit Test System).

[0005] Only a limited number of seeds or sprouts can be grown or produced, i.e. up to five seeds or sprouts with the PILLOW and PONDS units. Thus, a VEGGIE system equipped with these units can only ensure the growth and development of 40-50 sprouts.

[0006] The APEX-PGU unit allows for the cultivation of multiple sprouts. However, similarly to the PILLOW and PONDS units, it does not have any modular multi-functional configuration that would allow for the cultivation of microgreens in a second configuration in addition to seed germination, or the cultivation of whole plants over a longer period of time in a third configuration.

[0007] The XROOTS (eXposed Root On-Orbit Test System) arranged in the VEGGIE system is an electrically powered active unit, which allows for the cultivation of a larger number of plants, as well as the investigation of the development of hydroponic-aeroponic roots, and thus the fresh vegetable supply to the crew of space stations.

[0008] The disadvantage of the VEGGIE system is that the above-described units have to be separately delivered to the space station, which is a complicated and expensive logistical operation. It is an object of the invention to overcome the aforementioned drawbacks and to provide a plant growing device that enables extensive research on space plant cultivation.

[0009] The above-mentioned objects are achieved by providing a plant growing device for germinating plant seeds in a microgravity space environment and / or in a clinostat or in a normal gravity space environment, the device being provided with a passive water and / or nutrient supply system. The plant growing device comprises:

[0010] - a germination receptacle made of a non-transparent material provided with a liquid inlet connection element,

[0011] - a cover element connected to the germination receptacle via an intermediate piece,

[0012] - a high absorption capacity absorbent mat arranged on the lower surface of the germination receptacle,

[0013] - a germination module arranged in the germination receptacle between the absorbent mat and the cover element.

[0014] Various preferred embodiments of the invention are specified by the dependent claims.

[0015] The present invention will now be described in detail with reference to the accompanying drawings, in which:

[0016] Fig. 1 is a schematic side view of a device according to a first embodiment of the invention. Fig. 2 is a schematic side view of a device according to a second embodiment of the invention. Fig. 3 is a side view of an embodiment of the germination module of the device according to the invention.

[0017] Fig. 4 is a schematic side view of a device according to a third embodiment of the invention.

[0018] Figs. 5A-5D show the germination of Hungarian Enigma Hot (HEH) space bell pepper seeds using the device according to the first embodiment of the invention, wherein Figs. 5A, 5B and 5C are top views of the germination receptacle containing seeds on day 0, day 5 and day 10 of the germination, respectively, wherein Fig. 5D shows a side view of the germination strips containing 10-day-old HEH bell pepper sprouts prepared for morphometric measurement.

[0019] Fig. 6 shows the germination dynamics of HEH bell pepper seeds germinated in the device according to the first embodiment of the invention.

[0020] Figs. 7A-7D show the germination of Hungaro triticale seeds using the device according to the first embodiment of the invention, wherein Fig. 7A is a top view of the germination receptacle containing seeds on day 2 of the germination, Fig. 7B is a perspective view of the germination receptacle containing seeds on day 10 of the germination, Fig. 7C is a bottom perspective view of an embodiment of the germination module, Fig. 7D shows a side view of the germination strips containing 10-day-old Hungaro triticale sprouts prepared for morphometric measurement.

[0021] Fig. 8 shows the germination dynamics of Hungaro triticale seeds germinated in the device according to the first embodiment of the invention.

[0022] Figs. 9A-9D show the germination of HEH space bell pepper seeds using a device according to the third embodiment of the invention, wherein Fig. 9A is a perspective view of a germination receptacle provided with a germination cartridge holding plate containing seeds on day 30 of the germination, Figs. 9B and 9C are bottom perspective views of the germination cartridge holding plate provided with seed-holding cartridges accommodating absorbent cartridge strips containing germinated roots, and Fig. 9D is a top view of the soil-free space medium mixture placed in the additional chamber.

[0023] Fig. 1 and Fig. 2 illustrate the arrangement of the main units of a plant growing device according to a first and second embodiment of the invention. The plant growing device is provided with a passive water and / or nutrient supply system. The plant growing device comprises a germination receptacle 2 made of a non-transparent material, which may be formed as a box closed on one side. The germination receptacle 2 is provided with a liquid inlet connection element 8, which may be recessed in the side panel thereof, for supplying, for example, water or other nutrient liquid. The overall dimensions of the germination receptacle 2 are for example 10x10x4 cm.

[0024] The plant growing device has a cover element connected to the germination receptacle 2 via an intermediate piece 10. As shown in Figs. 1, 2 and 4, the intermediate piece 10 may be formed as a frame, the edge of which being releasably connected with a form-fit connection to the edge of the germination receptacle 2. Furthermore, the intermediate piece 10 may be provided with fastening elements, such as grooves or cutouts typically on its inner and outer surfaces for releasably securing the cover element.

[0025] As shown in Fig. 1, the cover element may be a flanged lid 4 made of a non-transparent material fitting to the inner surface of the intermediate piece 10 formed as a frame. The flange of the lid 4 may be provided with fastening elements, such as protrusions engaging in grooves formed on the inner surface of the intermediate piece 10. As shown in Figs. 2 and 4, the cover element may be a lid 9 made of a transparent material provided with slots 12 for ventilation, the lid 9 being typically higher than the cover 4. The cover 9 may be releasably connected to the upper part of the intermediate piece 10 formed as a frame by means of a snap-fit connection.

[0026] A high absorption capacity absorbent mat 7 preferably having one or more layers is arranged on the lower surface of the germination receptacle 2. The absorbent mat 7 may also extend over the side surfaces of the germination receptacle 2.

[0027] A germination module is arranged in the germination receptacle 2 between the absorbent mat 7 and the cover element. Fig. 3 shows an embodiment of the germination module. In this example, the germination module is a germination comb 1 provided with through openings in contact with the absorbent mat 7. The germination comb 1 having typically a rectangular shape is preferably provided with openings for receiving seeds on one side and with fastening elements, such as reinforcing patterns on the other side. The size of the openings of the germination comb 1 depends on the size of the seeds or the seed pouches to be inserted. The germination comb may be formed as a block of PLA material for example using three- dimensional printing. The dimensions of the block are for example 8x8x2 cm. The germination comb 1 preferably comprises ten 4 mm wide openings.

[0028] Furthermore, absorbent germination strips 5 suitable for receiving seeds are arranged along the length of the grooves of the germination comb 1, in order to accommodate the seeds to be germinated. The absorbent germination strips 5 may include several overlapping layers. The seeds to be germinated may be placed between two layers of the germination strips 5. If necessary, the seeds can be fixed with a guar gum-shaped adhesive. The plant growing device according to the embodiments shown in Figs. 1 and 2 advantageously comprises the germination comb 1 as shown in Fig. 3.

[0029] As can be seen in the second embodiment shown in Fig. 2, a sliding plate 3 guided by the intermediate piece 10 may be arranged on the upper side of the germination receptacle 2 above the germination comb 1. The sliding plate 3 may be provided with openings with the same geometric area as the openings of the germination comb 1. The sliding plate 3 may be displaced relative to the germination receptacle 2 between a closed and an open position for cutting and harvesting sprouted and growing sprouts, such as microgreens, that have sprouted through the gaps of the germination comb 1. The sliding plate 3 is preferably guided by two opposite horizontal grooves formed in the intermediate piece 10. As can be seen in the embodiment shown in Fig. 4, the germination module may be formed as a germination cartridge holding plate 14 provided with at least one seed-holding cartridge 13. The germination cartridge holding plate 14 may include holes arranged in a matrix pattern accommodating a cylindrical seed-holding cartridge 13 having preferably a through cavity. An absorbent cartridge strip 15 suitable for receiving seeds may be arranged in the seedholding cartridge 13 in contact with the absorbent mat 7. The absorbent cartridge strip 15 having preferably several overlapping layers may be arranged in the seed-holding cartridge 13 in an H-shape for example. One end of the absorbent cartridge strip 15 may be used for accommodating seeds and the other end extending from the seed-holding cartridge 13 may be in contact with the absorbent mat 7 placed on the lower surface of the germination receptacle 2.

[0030] In the embodiment shown in Fig. 4, the germination receptacle 2 may include an additional chamber 11 communicating with the liquid inlet connection element 8 arranged below the absorbent mat 7. The additional chamber 11 may contain a soil-free space medium mixture 16. The soil-free space medium mixture 16 may contain at least one of zeolite, lava stone, pumice stone, glass foam beads and slow-release nutrient granules in proportions depending on the use being made.

[0031] The absorbent mat 7, the germination strips 5 and the absorbent cartridge strips 15 are, for example, made of a so-called Swedish kitchen sponge material comprising a mixture of 70% wood cellulose and 30% cotton.

[0032] The operation of the plant growing device according to the invention will be described below.

[0033] The plant growing device according to the first embodiment of the invention shown in Fig. 1 is suitable for germinating plant seeds of different sizes, origins and preparations for research purposes. The germination operation can be carried out typically in 10-15 days. The plant growing device according to the second embodiment of the invention shown in Fig. 2 is suitable for producing so-called microgreens and wheatgrass sprouts of different sizes, origins and preparations suitable for human consumption. The germination operation can be carried out typically in 10-15 days. The plant growing device according to the third embodiment of the invention shown in Fig. 4 enables the growing of flowering and fruit-producing whole plants after germination of seeds of different sizes, origins and preparations. These operations are typically carried out within 30-120 days.

[0034] The seeds to be germinated are preferably placed in accordance with the germination direction between the layers of the germination strips 5 or the cartridge strips 15. Then, the germination strips 5 and the cartridge strips 15 containing the seeds are inserted into the openings of the germination module formed as a germination comb 1 and into the seed-holding cartridge 13 of the germination module formed as a germination cartridge-holding plate 14, respectively. Finally, the germination module is placed in the germination receptacle 2 so that the side of the germination module opposite to the direction of germination of the seeds comes into contact with the absorbent mat 7. Water or nutrient liquid supplied into the germination receptacle 2 via the liquid inlet connection element 8 is absorbed by the absorbent mat 7 and optionally by the germination strips 5 of the germination module made of absorbent material, or by the cartridge strips 15. If the germination receptacle 2 of the plant growing device is provided with an additional chamber 11, the additional chamber 11 is filled with a soil-free space medium mixture 16 comprising at least one of zeolite, lava stone, pumice stone, glass foam beads and slow-release nutrient granules in appropriate proportions according to the use being made. Water or nutrient fluid is introduced into the additional chamber 11 through the liquid inlet connection element 8.

[0035] At the beginning of the germination process, the germination receptacle 2 is closed with the intermediate piece 10 provided with the lid 4 made of a non-transparent material. After a given period of time, typically a few days, the intermediate piece 10 provided with the lid 4 is removed from the germination receptacle 2.

[0036] When it is desired to provide a closed environment for the germinated plants, the lid 4 made of a non-transparent material can be replaced with a lid 9 made of a transparent material. For this purpose, the lid 4 is removed from the intermediate piece 10 and the lid 9 is mounted on the intermediate piece 10 using appropriate fasteners. The lid 9 is then attached to the germination receptacle 2 via the intermediate piece 10 as shown in Fig. 2 or Fig. 4.

[0037] Before attaching the intermediate piece 10 provided with the corresponding cover element to the germination receptacle 2, the sliding plate 3 can be optionally inserted into the corresponding guiding grooves of the intermediate piece 10. The sliding plate 3 mounted on the plant growing device is first moved to the open state, and then the plants having reached the desired growth stage are cut by moving the sliding plate 3 to the closed state.

[0038] The absorbent mat 7 and the absorbent elements of the germination module ensure the supply of air, water and nutrients to the roots in normal terrestrial spaces, as well as in clinostats and microgravity or space conditions without using any additional electrically operated device, for example without using any pump. Thus, the plant growing device according to the invention can be operated based on the so-called passive water and nutrient supply principle by providing external light and appropriate conditions.

[0039] The experiments performed with the plant growing device according to the first and third embodiments of the invention will be described below with reference to Figs. 5A-5D, 6, 7A-7D.

[0040] Figs. 5A-5D and Fig. 6 illustrate the germination of Hungarian Enigma Hot (HEH) space bell pepper seeds in the plant growing device according to the first embodiment of the invention. In the present example a seed group containing one hundred seeds was investigated within the framework of a germination experiment performed over a 10-day period. The investigated seed group consists of a control subgroup of fifty untreated control seeds and a pretreated subgroup of fifty pretreated seeds. The surface of the seeds of both the control subgroup and the pretreated subgroup was disinfected with sodium hypochlorite and rinsed three times with sterile deionized water. The seeds of the control subgroup were dried at room temperature, typically for a period of seven days, until the seed group reached its original mass. Seeds of the pretreated subgroup were subjected to a selenization pretreatment. The seeds were imbibed for a specified period of time, typically during forty-eight hours, until the germination activation phase was reached in a selenization solution, typically containing 3% potassium nitrate and 5.3 pM sodium selenate. The pretreated seeds were then removed from the solution and dried at room temperature, typically for a period of seven days, until the seed group reached its original mass.

[0041] As shown in Fig. 5 A, the prepared dry HEH space bell pepper seeds were inserted using a pair of tweezers between the layers of the germination strips 5 with the micropyle facing downward. In this example, the germination strips 5 were 2 cm high and 17 cm long strips folded from their narrow side and placed in each opening of the germination module 1 formed as a germination comb. Ten seeds were inserted into one opening of the germination comb 1. The seeds of the control subgroup are located in the lower five rows, and the seeds of the pretreated subgroup are located in the upper five rows of the germination module of the germination receptacle 2 shown in Figs. 5A-5C.

[0042] An amount of 100 ml of sterile distilled water was added into the germination receptacle 2 via the liquid inlet connection element 8 and was absorbed by the absorbent mat 7. The germination receptacle 2 was then closed with the intermediate piece 10 provided with the lid 4 made of non-transparent material. After two days, the lid 4 was removed. The germination receptacle 2 being in the open state was placed in the plant growing chamber illuminated by LEDs of a so-called Microgreen germination device. A sixteen-hour long light program and an eight-hour long dark program were used. Subsequently, an amount of 25 ml of sterilized distilled water was introduced into the germination receptacle 2 via the liquid inlet connection element 8 on day 5 and on day 8 of the germination process.

[0043] The seeds of the control subgroup and the seeds of the pretreated subgroup were examined daily during the 10-day long germination process. Table 1 and Fig. 5 show the germination dynamics of HEH bell pepper seeds of the control subgroup and the pretreated subgroup.

[0044] Table 1: germination dynamics of HEH space bell pepper seeds of the control subgroup and the pretreated subgroup germinated in the plant growing device according to the first embodiment invention

[0045] Fig. 5.D shows 10-day-old HEH bell pepper sprouts prepared for morphometric measurement arranged in germination strips 5 taken out from the germination comb 1. The morphometric parameters characterising the development of HEH bell pepper sprouts of the control subgroup and the pretreated subgroup, i.e. the length, wet mass, dry mass and dry matter content of the sprouts, were measured and calculated. The measured and calculated morphometric parameters are summarized in Table 2.

[0046] Table 2: morphometric parameters of HEH space bell pepper seeds of the control subgroup and the pre treated subgroup germinated in the plant growing device according to the first embodiment invention The concentrations in phytochemical component of the HEH bell pepper sprouts of the subgroup pretreated with seleno-priming and the HEH pepper prouts of the control subgroup were measured on day 10 of the germination process using the UHPLS-ESI-MS method. Table 3 presents the results of this measurement.

[0047]

[0048] Table 3: Results of the concentration measurements in phytochemical component performed on 10-day-old HEH bell pepper sprouts of the control subgroup and 10-day-old HEH bell pepper sprouts of pretreated subgroup germinated in the plant growing device according to the first embodiment of the invention

[0049] Figs. 7A-7D and Fig. 8 illustrate the germination of Hungaro triticale seeds in a plant growing device according to the first embodiment of the invention. In the present example, a seed group containing eighty seeds was investigated within the framework of a germination experiment performed over a 10-day period. The germination process was repeated twice, so that a total of one hundred and sixty seeds were investigated. The seed group investigated within the framework of the germination process consists of a control subgroup of forty untreated control seeds and a pretreated subgroup of forty pretreated seeds. The surface of the seeds of the control subgroup and the pretreated subgroup was disinfected with sodium hypochlorite and rinsed three times with sterile deionized water. The seeds of the control subgroup were dried at room temperature until the subgroup reached its original mass, typically for a period of seven days. The seeds of the pretreated subgroup were subjected to a selenized pretreatment. The seeds were imbibed in a selenized solution containing 310 mM Ca-triphosphate and 5.3 pM sodium selenate for a given period of time, in this case for twenty hours, until the germination activation stage was reached. The pretreated seeds were then removed from the solution and dried at room temperature, typically for a period of seven days, until the seed subgroup reached its original mass.

[0050] As shown in Fig. 7A, the prepared dry Hungaro triticale seeds were inserted using a pair of tweezers between the layers of germinating strips 5 with the micropyle facing downward. In this example, the germination strips 5 were 2 cm high and 17 cm long strips folded from their narrow side and placed in each opening of the germination module 1 formed as a germination comb. Eight seeds were placed in one opening of the germination comb 1. The seeds of the control subgroup are located in the lower five rows, and the seeds of the pretreated subgroup are located in the upper five rows of the germination module of the germination receptacle 2 shown in Figs. 7A-7C.

[0051] An amount of 100 ml of sterile distilled water was added into the germination receptacle 2 via the liquid inlet connection element 8 and was absorbed by the absorbent mat 7. The germination receptacle 2 was then closed with the intermediate piece 10 provided with the lid 4 made of a non-transparent material. After two days, the lid 4 was removed. The germination receptacle 2 being in the open state was placed in the plant growing chamber illuminated by LEDs of a so-called Microgreen germination device. A sixteen-hour long light program and an eight-hour long dark program were used. Subsequently, an amount of 25 ml of sterilized distilled water was introduced into the germination receptacle 2 via the liquid inlet connection element 8 on day 5 and day 8 of the germination process.

[0052] The seeds of the control subgroup and the seeds of the pretreated subgroup were examined daily during the 10-day long germination process in the first and second germination processes. Table 4 and Fig. 8 show the germination dynamics of Hungaro triticale seeds of the control subgroup and the pretreated subgroup in the first germination process and the second germination process.

[0053] Table 4: germination dynamics of Hungaro triticale seeds of the control subgroup and the pretreated subgroup germinated in the plant growing device according to the first embodiment of the invention during the first germination process and the second germination process

[0054] Fig. 7D shows 10-day-old Hungaro triticale bell pepper sprouts prepared for morphometric measurement taken out from germination comb 1 and placed in germination strips 5. The morphometric parameters characterising the development of Hungaro triticale sprouts of the control subgroup and the pretreated subgroup, i.e. the length, wet mass, dry mass and dry matter content of the sprouts, were measured and calculated. The measured and calculated morphometric parameters are summarized in Table 5.

[0055] Table 5: Morphometric parameters ofHungaro triticale sprouts of the control subgroup and the pretreated subgroup germinated in the plant growing device according to the first embodiment of the invention

[0056] The concentrations in phytochemical component of Hungaro triticale sprouts of the subgroup pretreated with seleno priming and the Hungaro triticale sprouts of the control subgroup were measured on day 10 of the germination process using the UHPLS-ESI-MS method. Table 6 presents the results of this measurement.

[0057] Table 6: Results of the concentration measurements in phytochemical component performed on 10-day-old Hungaro triticale sprouts of the control subgroup and 10-day-old Hungaro triticale sprouts of the pretreated subgroup germinated in the plant growing device according to the first embodiment of the invention Figs. 9A-9D show the germination of Hungaro triticale seeds in a plant growing device according to a third embodiment of the invention. The Hungaro triticale seeds were placed in the absorbent cartridge strips 15 of eight seed-holding cartridges 13 formed on the germination cartridge-holding plate 14. Fig. 9A shows HEH space bell pepper plants on day 30 placed on the germination cartridge-holding plate 14 of the germination receptacle 2. In this germination process, a soil-free space medium mixture 16 containing zeolite, lava stone, pumice stone, and 50% by volume glass foam beads and slow-release nutrient beads was placed in the additional chamber 11 of the germination receptacle 2. As shown in Figs. 9B-9D, a part of glass foam beads of the soil-free space medium mixture 16 adhered to the young roots of HEH space bell pepper sprouts.

[0058] The advantage of the plant growing device according to the invention is that, thanks to its modular structure, it enables seed germination or plant growing in different growth phases. Another advantage of the plant growing device is that it enables to passively supply seeds, germs or plants with water and nutrients. The plant growing device can therefore be used on earth, in microgravity space and in a clinostat.

Claims

Claims1. A plant growing device for germinating plant seeds in a microgravity space environment and / or in a clinostat or in a normal gravity space environment, the device being provided with a passive water and / or nutrient supply system, characterised in that it comprises- a germination receptacle (2) made of a non-transparent material provided with a liquid inlet connection element (8),- a cover element connected to the germination receptacle (2) via an intermediate piece (10),- a high absorption capacity absorbent mat (7) arranged on the lower surface of the germination receptacle (2),- a germination module arranged in the germination receptacle (2) between the absorbent mat (7) and the cover element.

2. The plant growing device according to claim 1, characterised in that the germination receptacle (2) has an additional chamber (11) communicating with the liquid inlet connection element (8).

3. The plant growing device according to claim 1 or 2, characterised in that the germination module is a germination comb (1) provided with through openings in contact with the absorbent mat (7).

4. The plant growing device according to claim 3, characterised in that absorbent germination strips (5) suitable for receiving seeds are arranged along the length of the grooves of the germination comb (1).

5. The plant growing device according to claim 3 or 4, characterised in that a sliding plate (3) guided by the intermediate piece (10) is arranged on the upper side of the germination receptacle (2), the sliding plate (3) being provided with openings of the same geometric area as the openings of the germination comb (1).

6. The plant growing device according to claim 1 or 2, characterised in that the germination module is a germination cartridge-holding plate (14) provided with at least one seed-holding cartridge (13), an absorbent cartridge strip (15) suitable for receiving seeds being arranged in the seed-holding cartridge (13) in contact with the absorbent mat (7).

7. The plant growing device according to any of claims 2 to 6, characterised in that the additional chamber (11) contains a soil-free space medium mixture (16) comprising at least one of zeolite, lava stone, pumice stone, glass foam beads and slow-release nutrient granules.

8. The plant growing device according to any one of the preceding claims, characterised in that the cover element is a lid (4) made of a non-transparent material.

9. The plant growing device according to any one of claims 1 to 7, characterised in that the cover element is a lid (9) made of a transparent material provided with slots (12).

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