Patent Application
20140352210
The invention relates generally to a sonication and deposition process for the uptake of water or other substances along with dissolved substances into a seed, more specifically, to a method of treating seeds with sound waves for the purpose of imparting to the seed a memory for enhanced uptake of a substance that enhances a growth characteristic of the seed or resultant plant, or otherwise adds value to the seed during commercial processing.
Seed dormancy is a unique form of developmental arrest utilized by most plants to temporally disperse germination and optimize progeny survival. During seed dormancy, moisture content and respiration rate are dramatically lowered. The initial step to break seed dormancy is the uptake (deposition) of water necessary for respiration and mobilization of starch reserves required for germination. Deposition is a biphasic process: I) the physical uptake of water through the seed coat and hydration of the embryo; and II) germination as determined by growth and elongation of the embryonic axis resulting in emergence of the plumule and radicle. The two phases are separated temporally, and seed that have completed phase I is said to be “primed seed,” that is, primed for phase II: germination. Phase I of deposition is also used in the commercial processing of seed, i.e. wet milling fractionation of corn and the malting process for the fermentation of distilled spirits.
Priming of seed by the enhanced imbibing of water is advantageous to plant vigor, e.g. enhanced emergence, growth and yield characteristics. Seed priming also synchronizes the germination of seed resulting in a uniform field of plants that mature simultaneously for maximal yields at harvest. In addition to water, seed priming provides access to load the seed with nutrients, microorganisms, or pest inhibitors to promote seedling establishment. By adding a molecule to the seed during deposition phase I, the molecule or organism can be stored in the primed seed and therefore, be present at planting. The “loading of macromolecules” is very efficient in the seed when compared to the addition of similar molecules to the entire field. An example is the addition of fertilizer to stimulate root growth and hasten seedling emergence. The loading of the fertilizer into the seed prior to planting is more efficacious to the seedling and cost effective to the farmer. Other beneficial molecules to be loaded into seed are hormones such as the gibberelins/gibberellic acid to promote germination, cytokinins for cell elongation and inhibitors of abscisic acid to promote release from seed dormancy. Seed cultivars could be customized to specific growing regions by the addition of triazoles (plant growth regulators which moderate the effects of drought and high temperatures) or fungicides to inhibit the growth of fungi on seed and seedlings in cool, wet soil or insecticides to combat insects that attack seedlings such as corn rootworm. In addition to macromolecules, beneficial microorganisms such as Azospirillum or Rhizobium can be loaded during seed priming as a crop inoculant.
The commercial fractionation of corn begins with wet milling. Corn is a complex mixture of starch, protein, oil, water, fiber, minerals, vitamins, and pigments. Wet milling is the process of separating the corn components into separate homogenous fractions. In Iowa, approximately 20% of the 1 billion bushels of corn harvested each year is wet milled. The wet milling industry and collateral manufacturing represent a prodigious industrial effort. As the wet milling process is constantly refined by new technologies, novel by-products can be isolated in industrial quantities, e.g. ethanol, corn sweeteners, protein peptides, and vitamins C and E. The initial step in wet-milling, steeping, has not been altered by technological innovation. Steeping involves soaking the clean and dried corn (<16% water content) in warm water until it has swollen to 45% hydration. This process takes from 30-50 hr. at temperatures of 120-130.degree. F. During the steeping process, large quantities of water are moved through massive vats of corn in a countercurrent stream. Also, during this time, beneficial microorganisms such as the lactobacteria and Pseudomonas aeruginosa growing in the steep water aid in the proteolytic cleavage of corn proteins. However, the large volumes of steep water and the time required for hydration limit the effectiveness of the bacterial digestion. The digestion by-products are purified from the steep water primarily by evaporative concentration.
The malting process is the first step in the fermentation of grain to produce alcoholic spirits. The quality of the malt (and the resulting fermentation) is dependent upon the synchronous and efficient germination of the grain. Starches stored in the seed are converted into sugars during early stages of germination. At emergence, germination is halted and converted sugars are used during fermentation for the production of ethanol. Historically, the malting process was a labor-intensive task. The grain was spread onto a “malting floor, imbibed with water from overhead sprinklers, and turned by hand daily over the course of one to two weeks to release trapped heat and gases. At plumule emergence, the starches have been converted to sugars, the germinated grain is kiln dried and ground to form malt. Microbreweries and distilleries still use variations of this old malting technique to produce high quality malt. Some distilleries induce uniform germination by the addition of gibberllic acid (GA) to produce the highest quality of malt for fermentation such as in single malt scotch distillation. GA is the plant hormone, which regulates germination. Malt production of this quality is time consuming and expensive.
Normal Plant Germination
Water is the key factor that aids the germination of a seed. A seed can be prepared for germination by moistening. Care to be taken not to over soak the seed fully in water. When water penetrates the seed, the seed bulges as shown in
You will see a wide variety of trees in your surroundings. Trees play important role in maintaining ecosystem and keeping the environment refreshing and pollution-free. Whenever you watch small or big trees, plants or shrubs, you must be curious about their growth and life cycle. Life cycle of any plant is divided in different phases and seed germination is basic stage to start the growth of plant. You may think that seed is lifeless, but it is not true. It consists of plant in a resting, embryonic condition. Whenever it gets favorable environmental conditions, it starts to germinate. This process occurs through different steps in seed germination. Inactive seed lying in the ground needs warmth, oxygen, and water to get developed into plant.
Seed Structure
Seed coat is outer covering of seed, which protects embryo from any kind of injury, entry of parasites and prevents it from drying. Seed coat may be thick and hard, or thin and soft. Endosperm is a temporary food supply, which is packed around embryo in the form of cotyledons or seed leaves. Plants are classified as monocots and dicots depending upon number of cotyledons.
Requirements for Seed Germination
All seeds need adequate quantity of oxygen, water and temperature for germination. Some seeds also need proper light. Some can germinate well in presence of full light, while others may require darkness to start germination. Water is required for vigorous metabolism. Soil temperature is equally important for appropriate germination. Optimum soil temperature for each seed varies species to species.
Factors
There are several factors that can affect germination process. Over watering can prevent the plant to get enough amount of oxygen. If seed is deeply planted in soil, then it can make to use all the stored energy before reaching soil surface. Dry conditions can prevent germination, as seed doesn't get enough moisture. Some seeds have so hard seed coats that oxygen and water get through it. If soil temperature is extremely low or high, then it can affect or prevent germination process.
Steps Involved in Germination:
Germination in Dicots
During germination process of dicots, primary root emerges through seed coat when seed is buried in soil. Hypocotyl emerges from seed coat through soil. As it grows up, it takes the shape of hairpin, known as hypocotyl arch. Epicotyl structures, pluinule, are protected by two cotyledons from any kind of mechanical damage. When hypocotyl arch emerges out from soil, it becomes straight, which is triggered by light. Cotyledons spread apart exposing epicotyl, which contains two primary leaves and apical meristem. In many dicots, cotyledons supplies food stores to developing plant and also turns green to produce more food by the process of photosynthesis.
Germination in Monocots
During germination of grass seeds such as oats or corn, primary root emerges from the seed and fruit and grows down. Then, primary plant's primary leaf grows up. It is protected by a cylindrical, hollow structure known as coleoptile. Once the seedling grows above soil surface, growth of coleoptile is stopped and it is pierced by primary leaf.
Of course, all the seeds lying in ground are not lucky enough to get proper environment to germinate. Many seeds tend to get dried and cannot develop into a plant. Some seeds get sufficient amount of water, oxygen, and warmth, and seed germination starts.
Climate Change and Reduction of Plant Growth Times
As climate change globally can affect the time available for crop growth, generally making conditions for growth more severe and the growing periods shorter, the need to reduce and enhance seed growth and eventual plant production and harvesting within a shorter time period become apparent.
Thus, a need exists for (1) a method to enhance the ability of seeds to imbibe water and other substances and to (2) reduce the time needed for plant growth.
Sonification of Seeds
The invention describes a novel sonication and deposition process aimed at the treatment of seeds for the purpose of enhancing the speed of both germination of the seed and the resultant growth of the plant that emerges form the sonication treatment. Further the inventions uses a unique for of ultrasound to impart micro holes in the outer shell of the seed, thereby enabling the seed to increase it absorption rate of moisture and nutrients. The creation of the micro-holes in the seed shell structure enables the treated seed to germinate at a faster rate. In tests the savings in germination time is as much as 55% over conventionally grown seeds.
The invention also imparts an enhanced stable memory for subsequent uptake of a substance into a seed, particularly a substance useful for enhancing a growth characteristic of the seed with that characteristic transferring to an advantage for the resultant plant, and for the uptake of water into seeds for processing purposes. The growth characteristic is enhanced through the use of ultrasound, transmitted either using a sinusoidal ultrasonic transmission or one which employs alternating ultrasonic transmissions which rotate from one ultrasonic waveform to another, the ideal embodiment being saw tooth to square waveform.
In the way of further illustrative examples of applications of the present invention, it is anticipated that the present method is applicable to soften the outer shell layer of a seed's shell as seen in
The biochemistry of this process begins with the deposition of water through the seed coat and into the interior of the seed. Using corn seeds as an example: The water reacts with the cell embryo in a manner that releases a chemical known as gibberellic acid (GA), a plant hormone. The GA is transported throughout the seed until it arrives at the aleurone layer that surrounds the endosperm. In the aleurone layer 1, the GA acts to turn on certain genes in the nuclear DNA. The genes are transcribed resulting in the creation of messenger RNA, which interacts with a ribosome to begin the process of protein synthesis, or translation. The result is the creation of a protein called amylase. The amylase is transported out from the aleurone cells and into the endosperm. The amylase is an enzyme that acts as a catalyst for the hydrolysis of starch into sugar.
The sonication and deposition process of the present invention is directed in particular to such important agricultural seeds as corn, barley, and soybeans, wheat, tomatoes and other crops by the sonication of such seeds in a liquid medium, preferably water. Again, those of ordinary skill in the art will appreciate the applicability of the present invention to other seed types, without departing from the intended scope. The sonication is by the application of sound waves at ultrasonic frequencies from between about 15 kHz and 1750 kHz and preferably between about 20 kHz and 175 kHz, with an optimum near 23 kHz. Higher ultrasonic frequencies in the megahertz range are possible but there is a chance of seed damage. Intensity or power output can be varied in different seeds for increased speed of germination. In the following experiments just 0.5 watts of energy were employed but ranges could be from 0.125 mW/sq·cm to as high as 10 watts/sq·cm.
Ultrasonic energy is applied to the liquid and seed mixture by a sound transducer immersed in the liquid medium. While not wishing to be bound by any particular theory as to the mechanism of the subject of the invention, it is currently believed that the acoustic energy is carried through the liquid by oscillations of the liquid molecules in the direction of propagation. This produces alternating adiabatic compressions and decompressions together with corresponding increases and decreases in density and temperature. If the periodic decreases of pressure in the liquid are sufficiently high during the negative pressure phase, the cohesive forces of the liquid may be exceeded, at which point small cavities are formed by the process of cavitation. These small cavities then rapidly collapse, producing a very large amplitude shock wave with local temperatures up to a few hundred degrees centigrade or more. The collapse of the cavities is also known to create electrical discharges upon their collapse, giving rise to the effect known as sonoluminescence.
Critical to the process is the revolution of the seed within the liquid carrier or slurry, so that the ultrasound can reach all the surface of the seed during sonification.
With regard to the present invention, degassed distilled water requires an energy density level of approximately 1 to 10 watts/cm.sup.2 before cavitation occurs. By saturating the water with a noble gas, such as one or more of the inert gases helium, neon, argon, krypton, xenon, or radon, cavitation effects are seen at much lower energy density levels and the effects at energy density levels on the order of 1 to 10 watts/cm.sup.2 are greatly enhanced. This effect is believed to be due to the creation of microbubbles, which more easily form the small cavities upon the application of sonic energy. Additionally, the cavities in the presence of the saturated gas are believed to generate shock waves of larger amplitude upon collapse of the cavities than are achieved with degassed water. In particular, it is believed that when tap water was saturated with argon gas, helium gas, or argon and helium gasses, generally more dramatic uptake will be observed and such effects were reproducible from experiment to experiment. Other experiments in which the saturating gas was nitrogen also exhibited enhanced effects, but not nearly as pronounced as with argon. However, some experiments conducted with tap water and with boiled double distilled water also produced satisfactory results.
Since cavitation results in mechanical stress, sonication may create or enlarge fissures in the seed coat pericarp similar to scarification, a well-known process by which certain seeds, especially seeds with thick seed coats, are able to germinate. Scarification is believed to accelerate the deposition of water through the pericarp. Simple scarification is unlikely to explain the novel effect disclosed herein, since scanning electron micrographs suggest no increase in the number of fissures in treated seed, but do indicate a change in pericarp texture. It has been found that the sonication process accelerates the deposition of water. Cavitation may also result in physiological or biochemical changes in the seed that prime the germination process so that upon exposure of the seed to planting conditions, less time is needed for the seed to initiate germination, measured by the time when the radicle pushes through the pericarp. One mechanism proposed for causing physiological or biochemical changes is the production of free radicals by cavitation.
Reference is made to U.S. Pat. Nos. 5,950,362, 6,195,936, 6,250,011 and 6,452,609 which discuss the use of gases combined with cavitation forces to effect increased germination in certain seed stocks. These references rely upon cavitation forces to effect Scarification to the seed shells. However none of these works take note of the fact that convention ultrasound, developed by sinusoidal sonification, can impart extreme heat to a surface and thereby cause a melting of the seed shell as seen in
The invention consists of a sonication and deposition process for the uptake of water and/or other beneficial substances into a seed. The seed to be treated is immersed in water or other liquids. The seed is exposed to sound energy at frequencies between 15 kHz and 30 kHz for periods between about 1 and 15 minutes. The invention is the discovery that both cavitation ultrasound and the use of alternating wave form ultrasound can be employed to treat various seeds to increase the speed of germination of the seed, and therefore reduce the time for plant growth maturity.
Cavitational Ultrasound
Sinusoidal ultrasonic energy generates cavitational forces by the adiabatic collapse of micro bubbles in the liquid medium, particularly those bubbles that collapse at the surface of the seed. The ultrasonic cavitational forces impart an enhanced stable memory for the seeds to imbibe water and/or other substances beneficial to the seed and/or plant. The ultrasonically treated seed can be dried, stored, and later imbibed with a substance that enhances a growth characteristic of the seed or resultant plant. Upon germination, the plant maintains the enhanced growth characteristics.
Alternating Ultrasonic Transmission
Alternating the ultrasonic transmission where the first part of the transmission is a saw tooth wave form lasting 50 milliseconds, followed by a square wave form lasting 50 milliseconds, in the preferred embodiment but other variations of the alternating sonic wave form can be employed. The alternating ultrasonic transmission applies the ultrasonic energy and the effect of faster seed germination more effectively than the use of Sinusoidal cavitational ultrasonic energy generates seed germination.
A purpose of the invention is to impart upon seeds through a sonication and deposition process a memory for the enhanced uptake of a substance with a beneficial growth characteristic.
A purpose of the invention is to impart upon seeds through a sonication and deposition process a further means of reducing the time needed for germination of the seed, and therefore to speeding the maturing of the resultant plant.
These and other objects of the invention will be made clear to a person of ordinary skill in the art upon a reading and understanding of this specification, the associated drawings, and appending claims.
Mechanics of the Invention
There are two differ′ent methodologies for generating an ultrasonic transmission; (1) convention sinusoidal ultrasound which imparts heat to a subject through the process of cavitation as seen in
In
A typical sinusoidal ultrasound transmission could have been employed successfully if the seed had been rotated under the ultrasonic transmission, so that the damaging effects of sinusoidal ultrasound are minimized to the treated seed.
Under
The alternating waveform uses an ultrasonic duty cycle which is variable as to the time element employed in any timing of a particular waveform action. As an example:
Description of the Laboratory System
After sonication, the seeds are dried, and then placed on a water-saturated filter pad, or in some cases, in wet soil, to induce germination. The temperature during germination has been varied to analyze the effect of the treatment on germination at various temperatures. Measurements which have been monitored in different experiments have included the time of emergence of the primary root, the time of emergence of secondary roots, the time for emergence of coleoptile, the root length and weight, the root area, the estimated volume of the root, the coleoptile length and weight, and the uptake of water. The seeds tested were first generation (F.sub.1) hybrid seed corn.
Continuous Apparatus
Ultrasonic Flow Cell Device
The Tip 63 must be immersed in the liquid medium. The transducer is connected to an ultrasonic frequency generator. In the preferred embodiment of this Flow cell system, the sound transducer horn 64 is a piezoceramic transducer, Model VCX600 obtained commercially from Sonics and Materials, Inc. Alternative transducers may be used. Magnetorestrictive transducers are capable of delivering higher levels of sound energy to the liquid media and may be preferable if higher sound densities are desired, for example if large quantities of seed are to be sonicated. The frequency generator 9E is a Model 33120Q obtained commercially from Hewlett Packard and is matched to the transducer horn. It has a frequency range of between 15 kHz and 30 kHz and can supply between 0 and 500 watts to the sound transducer horn. In the experiments described herein, the power densities were between 30 watts per cm.sup.2 and 80 watts per cm.sup.2, although given the rated efficiency of the sound transducer 64 higher power densities can be achieved in the housing 60. Typically this apparatus will develop a sinusoidal ultrasonic waveform which can impart cavitation effects, as seen in
Seeds are generally added at up to 30% in water by weight to produce seed slurry which is then added to the flow cell. The water solution could be tap water, or water that has been enhanced with a nutrient solution as an enhancer for the seed being ultrasonically processed. Nitrogen based or fertilizer based solutions are possible liquid vehicles. A stirrer may be employed at the inflow to the flow cell to cause the seeds within the slurry to rotate under the ultrasonic transmission. The seed mixture 40 can be processed once through the ultrasonic processor or may be subject to multiple cycles by recycling it through the processor more than once. Once processed the seed slurry are conveyed to a filter/dryer to remove the liquid and produce a dry seed product.
Continuous Ultrasonic Flow Pipe—
In order to provide a continuous ultrasonic treatment system a device involving an Ultrasonic Flow pipe 71 as illustrated in
Transducer Design
In
The transducer array shown in
A series of experiments were performed to demonstrate the effectiveness of the methods of the present invention. Experiments were conducted using the laboratory apparatus shown in
The ultrasonic settings for each experiment were:
Seed slurry was developed consisting of 30% seeds in 70% tap water at ambient temperature. The seeds were added to the beaker of water right before the experiment and were sonicated for differing exposure times.
Samples were taken at each exposure time, filtered using a Buchner funnel and then allowed to air dry over night. The seeds were each then placed in a separate aquarium which was filled with potter soil at a depth as recommended for that seed. For example wheat was recommended in soil to a depth of 1.5 inches while carrots were to 7.5 inches. The aquariums were then placed on a window ledge to allow sunlight to reach the aquariums, but the aquariums were not exposed to the outside elements during the incubation period.
The seeds in the aquariums were examined every morning until they began to bud and emerge from the soil. The time to germination were compared to a control group that was not treated with ultrasound. The results are as indicated in the following experimental tables.
The summary of the experiments is listed below. In each case of ultrasonic sonification the sonicated seed germinated at a faster rate. The control seeds germinated in 7-14 days while the sonicated seeds germinated in 4 to 6 days. The germination savings in terms of days for germination ranged from −41% for the sonicated wheat seed to −56% for the carrots.
After being germinated the sonicated and the control seeds were then transferred from the incubating Petri aquariums to an outside Test Farm, where the seeds were planted to the recommended normal depth for that plant in conventional soil and allowed to grow into a mature plant.
Generally the control plants matured in 75-89 days, approximating the listed plant growth times. The sonicated plants took from 35-42 days to mature and were comparable in size, integrity and even fruit size and characteristics for the tomato crop to the control unsonicated group.
Sonication saved 33 to 52 Days in harvest time.
Planting Trial Results for Ultrasonically Treated Tomato Seeds, Grown to Full Maturity and Harveted.
While the above experiments were conducted using the apparatus described in
Cavitation generates heat energy as well as mechanical forces, as shown in
Many of the seeds treated with sinusoidal ultrasound indicated structure damage after just 5 minutes of exposure, see
Therefore the preferred embodiment is one using the alternating ultrasound treatment, but conventional sinusoidal ultrasound may still be preferable in certain seed cases, as long as the seed is rotated under the ultrasonic transmission.
The experimentation listed above showed that ultrasound-induced water uptake represents a unique event dissociable from normal water uptake. The differences in uptake rates of sonicated and the control soaked seeds showed that the sonicated seeds exhibit a much faster rate of germination than the non-sonicated seeds.
These results demonstrate that ultrasound-stimulated seeds probably have faster rates of water uptake is achieved very rapidly compared to the rates of water uptake of just soaked seeds. Thus, the sonication process fundamentally enhances the rate of uptake of substances into the seeds, speeding both seed germination and the growth of mature plants and crops. This process may therefore be used to reduce the time-to-harvest for many crops by first ultrasonically treating the seeds.
Additionally, results demonstrate that ultrasound treatment alters seed without negatively affecting the proportion of seeds that germinate. Ultrasound treatment causes an accelerated increase in seed hydration. The effect of ultrasound is not to drive water into the seed, but rather to alter the seed so that it will take-up water at an enhanced rate, even in the absence of ultrasound. This enhanced deposition effect is stable. It is maintained when seed is dried and stored after ultrasound treatment. Ultrasound does not negatively affect germination. The ability to separate the sonication and deposition steps without diminishing the enhanced deposition effect results in significant practical advantages. The seed can receive ultrasonic cavitational treatment at a first point of time, and after waiting a predetermined period of time, the seed will exhibit an enhanced ability to imbibe a substance. This allows for sonicating the seed, and storing the seed until planting or processing begins. At this later date, the decision about what substance to imbibe into the seed can be specifically tailored to the then existing planting, growth, or processing conditions. This allows for more efficient and timely preparation of the seed. Further, the imbibing step does not require sophisticated equipment or technical expertise, and thus can be performed in the field.
Those of ordinary skill in the art will understand that by demonstrating the basic technique of enhanced deposition with a substance like water, any other type of substance can be imbibed into the seed in the same manner. As mentioned hereinabove, these substances can include water, pesticides, insecticides, herbicides, fungicides, and growth hormones; however, the applicability of the invention is not limited to these substances. The enhanced deposition method can be used with substances that enhance any growth characteristic of the seed and the resultant plant, or otherwise add value to the seed during commercial processing. For example, the method of the present invention could be used to imbibe into a seed substances that would inhibit germination for certain predetermined periods of time. Delaying germination in this manner would prove beneficial in commercial farming by allowing growers to plant seed prior to the occurrence of optimum planting or germination conditions. This would relieve growers of the burden of planting their entire crop at once when the soil and weather conditions reach a preferred state for planting. Thus, the substances contemplated for use with the present invention need not necessarily be substances that make a plant grow faster, stronger, or resistant to pests in some manner.
Crops emerging from ultrasonically treated seeds in the manners described above tend to have full growth plants and far less time to harvest than untreated crops.
Although the invention has been described with respect to a preferred embodiment thereof, it is to be also understood that it is not to be sole limited since changes and modifications can be made therein which are within the full intended scope of this invention as defined by the appended claims.
