MXNL05000044A - Seed-germination and seedling-elongation stimulant based on larrea tridentata extracts. - Google Patents

Abstract

The present invention refers to the use of water-soluble extracts of Larrea as promoters for the germination of seeds and the elongation of epicotyls and ridicles, and increasing the dry biomass in seedlings of diverse agricultural crops. The invention includes and describes a method for applying bioproducts, which is based on soaking the seeds in aqueous solutions of Larrea tridentata extracts for a predetermined period of time before setting the same under suitable conditions for the germination thereof and the development of the seedling. The Larrea tridentata extracts may be available in water-soluble powders or a liquid solution, which may be used alone, mixed together, or with diverse agrochemical products, such as growth regulators, pesticides, fertilizers or nutrients. The mixtures may be useful for preparing aqueous solutions at different concentrations, which depends on the type of seed and the desired results.

Description

STIMULANT OF GERMINATION OF SEEDS AND ELONGATION IN PLANT WITH BASE IN EXTRACTS OF Larrea tridentata INTRODUCTION The objective of this document is to describe and protect the use of hydrosoluble extracts of Larrea tridentata as promoters of seed germination and the elongation of seedlings and radicles in seedlings, as well as the increase in the dry mass in seedlings of various agricultural crops. . The invention also provides the method of application, which is based on soaking the seeds in aqueous solutions of the extracts of Larrea tridentata for a certain time before being placed in conditions conducive to its germination and the development of the plants. This method and the extracts indicated here can be used as promoters or enhancers of cell germination and elongation in the initial phase of growth, in numerous plant species that may be of the grass family (corn, wheat, barley, oats) , etc.); in legumes (beans, soybeans, peas, lentils, alfalfa, etc.), as well as in vegetables (lettuce, broccoli, tomato, chili, etc.).

As a result of the application of these products it is possible to increase the percentage of germination of seeds, promote the growth of radicle and seedling in seedlings, as well as increase the production of dry biomass of the seedlings. Extracts of Larrea tridentata have the presentation in the form of water-soluble powders or liquids, which can be prepared at different concentrations of active ingredient, and mixed or formulated with other bioactive compounds, both of vegetable, animal, or mineral origin. can be used alone or mixed with other products for agricultural use to prepare aqueous solutions at different concentrations.

BACKGROUND OF THE INVENTION Seeds play an important role in the agricultural production process. Although they are the best vehicle for bringing technological advances to the field, they can also become transmitters of phytopathogenic organisms from one area to another. In suitable conditions for their development, these organisms cause a detriment in the yield of the crops and in the quality of the new seeds [International Workshop on Identification of Fungi and Stramenopiles Transmitted by Seeds. Texcoco, Mex., August 26 to 30, 2002]. Currently, there is a great world demand for high quality seeds and health, because working with products of these characteristics allows to have greater productive certainty and ensure a good harvest.

Most producers of horticultural and forage crops in Mexico import the seed. The rest is produced in small volumes or collected directly from the field, with a germinative quality that does not meet the agronomic requirements and, in addition, with problems of genetic identity and purity, which puts at risk the entire production process and the profitability of the crop .

In order to obtain high quality and yield crops, as well as to optimize agricultural inputs such as fertilizers, pesticides and other agrochemicals, the treatment of seeds before planting has been extensively used. With this it is possible to break dormancy or dormancy, accelerate the time of germination and / or improve the percentage and uniformity of germination in various crops.

Just as good germination of the seed is important for the proper establishment in the field of any crop, a good development of the root system is also indispensable. A well-developed root, in addition to improving the anchoring of the plant, absorbs a greater amount of water and nutrients because it explores a greater volume of soil. It also has a greater capacity to store water and minerals and to lead them to the stem and leaves.

In the case of crops that grow under arid conditions, the storage of water in the root system works as a physiological adaptation strategy to deal with the lack of water in the initial stages of establishment of the plants. Because the absorption of water is proportional to the root density, it is obvious the benefit that can be achieved by promoting the cellular elongation of the roots.

The products used to improve the germination of seeds and / or stimulate cell elongation in seedlings have been many and varied. For this you can use hot water or at room temperature, hydrogen peroxide, hormonal substances such as gibberellic acid (GA) and indoleacetic acid (IAA) and a wide variety of organic and inorganic chemicals that function as growth regulators [Leslie S. Katzman et al., HortScience 36 (5), 979-981 (2001)].

It is important to make a distinction between the terms "plant hormones" and "plants growth regulators". The first are natural substances produced in a part of the plant, which are transferred or translocated to other parts to control activities of the same plant. Growth regulators that include plant hormones, can be natural or synthetic and are defined as organic compounds other than nutrients, which used in small amounts can encourage, inhibit or modify various physiological processes of plants [Hudson Hartmann et al. , p. 133 to l41 in "Plant Science, Growth Development, and Utilization of Cultivated Plants," Prentice-Hall, Inc., 1981].

The main plant hormones are auxins, gibberellins, cytokinins and ethylene. The precursors of these hormones are the amino acid methionine and linoleic acid [Hudson Hartmann et al., P. 133 to 141 in "Plant Science, Growth, Development and Utilization of Cultivated Plants," Prentice-Hall, Inc., 1981]. The most common auxin is the AJA that the plant synthesizes from the amino acid tryptophan in the cells of the apical meristem of the stem and branches, as well as in the leaf buds when they are in development. The main action of the AIA is to promote cell elongation. The gibberellins (AG) are produced in the embryo or cotyledons of the seeds, at the apex of the stem of the plants, mainly in the small leaves in formation, and in large quantities, in the root system. Although the main function of AG is to stimulate cell division and elongation, it is known that in several species it also interacts with phytochromes to stimulate seed germination, bud opening, shattering of dormancy and flowering [J.A. Robert and R. Hooley, "Plant Growth Regulators", Chapman & Hall, 1988]. The Cytokinins are found in large quantities in the embryo of seeds and in developing fruits, especially in all tissues with large cell division. They act in cell division and elongation, tissue differentiation, dormancy, flowering and retarding the aging of the leaves. For its part, ethylene is a gas produced in meristems actively growing in the plant, in mature fruits and flowers and in some bent or wounded tissues. It acts by stimulating flowering in crops such as pineapple, as well as breaking dormancy in potato tubers.

Larrea tridentata (D.C.) Coville, belongs to the family Zygofiláceas (Zygophyllaceae). It is a xerophite shrub that grows in the arid zones of northern Mexico and the southwestern United States, specifically in the Chihuahuan, Sonoran and Mojave deserts. A variant of this species is found in the arid zones of Argentina and has been classified as Larrea divaricata.

Larrea tridentata leaves contain a wide variety of chemical compounds such as: phenols, lignans, agrifone fiavonoids, flavonoids glycosides, saponins, triterpenes, volatile monoterpenes, oxygenated monoterpenes, aromatics, steroids, tannins, waxy esters, amino acids, vitamins and minerals, among other compounds. The content of amino acids and minerals can be around 30% (dry weight basis). Taking into account that these compounds are in many cases the precursors of hormones and growth regulators in plants, it was considered the possibility of evaluating the water soluble extracts of L. tridentata resin to stimulate the germination of seeds, as well as the cellular elongation of several tissues of the seedlings obtained from these seeds.

The irrational use of agrochemicals of synthetic origin such as fertilizers, growth regulators and pesticides has brought with it numerous side effects, among which the development of resistant populations of insects, fungi and bacteria, the resurgence of new pests, the intoxication of humans stand out. , the elimination of beneficial fauna, the increase in production costs and, the contamination of crops and the environment. This situation has led to a growing demand for organic vegetable products to be used in agricultural and forestry production systems.

The novelty of the present invention lies in the use of Larrea tridentata extracts as promoters of seed germination and cell elongation in the root system and the seedling seedling. The invention also provides the method of application, which is based on soaking the seeds in aqueous solutions of Larrea tridentata extracts for a certain time before being placed in conditions conducive to germination and development of the seedling.

DESCRIPTION OF THE INVENTION The present invention relates to the use of powder or liquid extracts of Larrea tridentata as promoters of seed germination and cell elongation in the root system and seedling seedling. The extraction process of Larrea tridentata resin with methanol and ethanol, as well as the process to make it water soluble, are described right away. The dried leaves of L. tridentata were immersed in methanol or ethanol for 24 h at room temperature. The solution thus obtained was filtered and then subjected to evaporation to remove the remaining solvent. After this process, the recovered solid product was treated with a 3% by weight aqueous sodium hydroxide solution. The product was dried in a forced air oven for 5 to 7 days, at 65 ° C. Once dried, the recovered solid product was ground in a mortar to obtain a powder that is soluble in water.

The products evaluated in the present invention are the methanolic and ethanolic extracts of Larrea tridentata, which are water-soluble powders that can be used alone or mixed together, or mixed with other agrochemicals, which can act as growth regulators, pesticides, fertilizers or nutrients.

Extracts of L. tridentata alone or in the aforementioned mixtures can be used in the form of solutions, suspensions, emulsions or pastes. The forms of application, as well as the concentrations used, depend entirely on the types of seeds to be treated or on the results to be obtained. As a general rule they will be applied in the form of aqueous solutions.

The seeds that can be treated with the extracts of L. tridentata for the purpose of promoting their germination, as well as promoting cellular elongation of radicles and seedlings in the seedlings, in addition to increasing the production of dry biomass per seedling include, but not are limited to legumes such as beans, soybeans, peas, lentil, alfalfa, etc .; Grasses such as corn, wheat, oats, barley etc; Solanaceae such as tomato, chili, tomatillo etc .; Cucurbitaceae such as broccoli, cauliflower, cabbage or cabbage, etc .; Amaryllidaceae such as onion, garlic, etc., and Compositae such as lettuce, among many species of agricultural utility.

The method to be used in the application of the extracts would be any method conventionally used for the application of commercial products that promote the germination of the seeds and / or the root growth and the seedling of the seedlings. It generally consists of soaking or imbibing the seeds in the solutions containing said promoters, for a certain time prior to the sowing of the seeds.

In practice, generally from 50 ppm to around 10,000 ppm, and preferably from approximately 250 ppm to approximately 3000 ppm of the extract of Larrea tridentata dispersed in water, they are effective when applied to seeds to promote their germination as well as to promote cellular elongation of the radicles and seedlings of the seedlings, in addition to increasing the amount of dry biomass per plantlet. Depending on the type of seed that you want to treat, the imbibition times can be from 1 to 12 hours, however, times of 1 to 3 hours are effective to achieve the benefits already mentioned.

BEST METHOD FOR CARRYING OUT THE INVENTION The following are some examples of the evaluations that were made to the extracts of Larrea tridentata. Likewise, the method followed for treating the seeds and the results obtained in said evaluations is mentioned. These examples are offered to further illustrate the novelty and usefulness of the present invention, but not with the intention of unduly limiting it. In all the examples, the evaluation products refer to the hydrosoluble, methanolic or ethanolic extracts of the leaves of L. tridentata. The evaluation product can be liquid or in the form of powder, which is dissolved in water, in both cases, can be used to treat the seeds alone or mixed with different doses of gibberellic acid AG3, to prepare solutions at different concentrations and enhance the effect of the same on seeds of different crops.

EXAMPLE 1: Test to compare the germination of lettuce, onion and bean seeds that were imbibed in water, in aqueous solutions of a water-soluble, methanolic or ethanolic extract of L. tridentata and in mixtures of the methanolic extract with gibberellic acid.

The seeds used in this trial were two horticultural crops (lettuce and onion) and two legumes (two varieties of beans). The seeds received a treatment that consisted of immersing them in containers containing aqueous solutions of L. tridentata extract at different concentrations, allowing them to soak or imbibe during a determined time, which in this case was 1.5 hours. At the end of the imbibition period, the seeds were removed from the containers and placed on a piece of Anchor absorbent paper with dimensions of 25 x 45 cm, which was previously moistened in running water. In each paper portion, 25 seeds were planted, orienting them with the hilus towards the same side. Later the paper was rolled up and both ends were tied with rubber bands. The rolls of paper containing the seeds were placed in polyethylene bags, which in turn were introduced in a germination chamber with constant temperature of 25 ° C, with daily cycles of 12 light hours and 12 hours of darkness for 7 days.

Table A presents the comparison made between the percentage of germination obtained by treating the seeds with water (control) and with aqueous solutions of the extract of L. tridentata in four concentrations. In this table it can be seen that the percentage of germination in the four agricultural species was consistently greater when they were treated with extracts of L. tridentata in any of the concentrations used.

Table IA. Germination percentage of Clemente lettuce seeds, onion Tribute variety, and beans of the Pinto Villa (PV) and Bayo Zacatecas (BZ) varieties treated with aqueous solutions of a water-soluble, methanol extract of L. tridentata Dose of Methanol Extract of SPECIES L. Tridentata (ppm) Water 250 500 1000 2000 (Control) Lettuce 99 100 99 99 98.0 Onion 95 86 85 94 81.0 Bean PV 84.33 86.66 82.66 84 71.66 Bean BZ 98.33 96.66 98.33 97.33 92.0 Aqueous solutions containing 1000 ppm of the methanolic extract of L. tridentata mixed with the phytohormone gibberellic acid at concentrations of 270 were also prepared., 540 and 810 ppm. This was done for the purpose of comparing the effect of using the extract alone and mixed with this hormone, which is extensively used in a practical and commercial way to stimulate seed germination. Table IB shows the germination values of bean seeds of the Pinto Villa and Bayo Zacatecas varieties treated or imbibed in the aforementioned solutions. In this table it is appreciated that the extract only of L. tridentata improved the germination in the two bean varieties and even, in some cases, its results were better than those obtained with the mixtures.

Table IB. Seed germination percentage of two bean varieties treated with aqueous solutions - 1000 ppm of a methanol extract of L. tridentata and mixtures of 1000 ppm of the extract evaluated with three different doses of gibberellic acid (AG3).

Dose of AG3 plus Extract only 1000 ppm of i. Tridentata of L. tridentata Control VARIETY 270 ppm 540 ppm 810 ppm 1000 ppm (water) Pinto Villa 783 86 \ 0 87! 8O0 76.5 Bayo 94.50 95.50 97.50 98.50 93.00 Zacatecas EXAMPLE 2: Test to compare the growth of the radicle of lettuce seedlings, onion and two varieties of beans from seeds imbibed in aqueous solutions with different concentrations of a water-soluble, methanolic extract of L. tridentata.

The methodology of this example is the same as the one mentioned in example 1. Table 2 compares the growth observed in the radicle of lettuce, onion and bean seedlings, from seeds treated with aqueous solutions of the L extract. tridentata, measured eight days after the seeds were germinated on Anchor paper. In this table you can see that the seedlings of the species mentioned were stimulated with the evaluated extract, since they consistently showed greater growth than those imbibed in water (control). It is important to note that in the case of lettuce seedlings, the effect of the extract at doses of 500 and 1000 ppm meant that the length of the radicle was 78% higher than the length of the radicle of the control.

Table 2. Radicular growth (cm) of lettuce seedlings Clemente variety, onion Tribute variety and beans of the varieties Pinto Villa (PV) and Bayo Zacatecas (BZ) from seeds treated with aqueous solutions of a water-soluble, methanolic extract of L. tridentata.

Dosage of Extract of L. Tridentata SPECIES (ppm) Water 250 500 1000 2000 (Control) Lettuce 16.12 16.55 16.50 10.17 9.25 Onion 13.45 14.40 13.12 10.60 11.87 Beans PV 19.24 19.35 19.31 18.77 17.24 Beans BZ 16.05 15.62 15.54 16.76 14.10 EXAMPLE 3: Test to compare the growth of the seedling of bean seedlings from treated seeds, at two imbibition times, in aqueous solutions of the water soluble methanolic extract of L. tridentata and in mixtures of the same extract with gibberellic acid.

The methodology followed in this example is the same as that described in example 1. Table 3 shows the comparison of the length of the talluelo (plúmula) of seedlings of Bayo Zacatecas variety, measured eight days after having started to germinate the seeds in paper Anchor. In this table it can be seen that the seedlings of the seeds treated with the L tridentata extract and with the mixtures of the same extract with gibberellic acid, consistently showed a greater growth than those imbibed in water (control).

Table 3. Stem growth (cm) of Bayo Zacatecas variety (BZ) bean seedlings from seeds treated with aqueous solutions of 1000 ppm of the water soluble methanolic extract of L. tridentata and with mixtures of 1000 ppm of the same extract with three different doses of gibberellic acid (AG3).

Dose of AG3 plus Extract only 1000 ppm of L. tridentata of L. tridentata Control SPECIE 270 ppm 540 ppm 810 ppm 1000 ppm (water) Bean BZ 19.36 19.13 20.86 19.45 13.65 EXAMPLE 4: Test to compare the production of dry biomass of bean seedlings from imbibed seeds, at three different times, in aqueous solutions of the water soluble methanolic extract of L. tridentata.

The methodology followed is the same as that described in Example 1, except that in this case the imbibition time of the seeds was varied (1.5, 3.0 and 4.5 hours). At the end of these periods, the seeds were taken out of the containers and arranged to germinate as indicated in example 1. Table 4 shows the results obtained with respect to the effect of the extract of L. tridentata on the production of biomass. dry of bean seedlings Pinto Villa variety, measured eight days after the seed was germinated on Anchor paper. This table shows that the average production of dry biomass was consistently higher with respect to the control, in the seedlings obtained from seeds treated with the extract of L. tridentata. With respect to the time of soaking or imbibition of the seeds in the solutions, the best results were obtained for the times of 1.5 and 3 hours.

Table 4. Production of dry biomass of Pinto Villa variety bean seedlings from seeds subjected to different imbibition times in aqueous solutions of the water soluble methanolic extract of L. tridentata.

L. Tridentata Time (ppm) Water (hours) 250 500 (Control) 1.5 92.88 92.54 87.63 3.0 97.33 91.11 84.64 - 4.5 88.96 88.59 79.73

Claims (6)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. The use of water-soluble resin extracts of Larrea tridentata leaves as promoters of seed germination; promoter of the elongation in talluelos and raicillas; as well as promoters of the increase in the amount of dry biomass of various species of plants grown for agricultural purposes.

2. The use of water-soluble extracts of Larrea tridentata according to claim 1, characterized in that they can be used alone or mixed together, or mixed with other agrochemicals, which can act as growth regulators, pesticides, fertilizers or nutrients, besides that these can be of natural or synthetic origin. The amount of the components of the mixtures, as well as the weight ratios between these components, depend entirely on the types of seeds to be treated or the results that are desired.

3. The use of water-soluble extracts of Larrea tridentata according to claims 1 and 2, characterized in that they can be used in the form of solutions, suspensions, emulsions, mini-emulsions, microemulsions or pastes. Although as a rule they will be applied in the form of aqueous solutions. The concentrations of the extracts, when used alone, or the concentrations of the mixtures of extracts with other components in the solutions, depend entirely on the types of seeds to be treated or on the results obtained. they want to obtain. In practice, from 50 ppm to about 10,000 ppm, and preferably from 250 ppm to around 3000 ppm, can be used. The use of water-soluble extracts of Larrea tridentata according to claims 1, 2 and 3, characterized in that it is applied to seeds of crops including, but not limited to legumes such as beans, soybeans, peas, lentils, alfalfa, etc.; Grasses such as corn, wheat, oats, barley etc; Solanaceae such as tomato, chili, tomatillo etc .; Cucurbitaceae such as broccoli, cauliflower, cabbage or cabbage, etc .; Amaryllidaceae such as onion, garlic, etc., and Compositae such as lettuce, among many species of agricultural utility.

4. A method for promoting seed germination, characterized in that before seeding the seeds, they are soaked or imbibed in an aqueous solution prepared according to claims 2, 3 and 4, during a period that can be from 1 to 12 hours, although more specifically from 1 to 3 hours.

5. A method to promote the growth of the radicle and seedling seedling, characterized in that the seedlings come from seeds that before being sown, were soaked or imbibed in an aqueous solution prepared in accordance with claims 2, 3, 4 and 5, during a period that can be from 1 to 12 hours, although more specifically from 1 to 3 hours.

6. A method for increasing the amount of dry biomass of plantlets, characterized in that the seedlings come from seeds that before being sown, were soaked or imbibed in an aqueous solution prepared in accordance with claims 2, 3, 4, 5 and 6 during a period that can be from 1 to 12 hours, although more specifically from 1 to 3 hours.