Methods for improving ramie's resistance to heavy metal stress

Abstract

The invention discloses a method for improving ramie's resistance to heavy metal stress, and relates to the technical field of ramie planting. The method comprises the following steps: before transplanting ramie seedlings, spraying a citric acid aqueous solution on the soil surface until the soil surface is completely moistened, and then plowing; performing a first light treatment at the ramie seedling stage, the first light treatment using a mixed light source of red light, green light and blue light; performing a second light treatment at the ramie vigorous growth stage, the second light treatment using a mixed light source of red light and blue light. The method of the invention is simple, can avoid the quality reduction of ramie due to heavy metal stress, and is suitable for promotion.

Description

Technical Field

[0001] The invention relates to the technical field of ramie planting, in particular to a method for improving ramie's resistance to heavy metal stress. Background Art

[0002] Ramie (scientific name: Boehmerianivea (L.) Gaudich.) is a subshrub or shrub plant of the Urticaceae family and the genus Ramie. Other names: wild hemp, wild ramie, domestic hemp, ramie, green hemp, white hemp. Ramie is one of the important fiber crops in ancient China. Ramie is more adapted to temperate and subtropical climates.

[0003] Ramie leaves are a nutrient-rich feed with a high protein content. Ramie roots contain the medicinal ingredient "ramie acid", which has the effects of nourishing yin, calming the fetus, treating antenatal and postnatal anxiety, and treating furuncles. Ramie bones can be used as raw materials for papermaking, or to make fiberboards for furniture, siding and other purposes. Ramie bones can also be used to make wine and sugar. Ramie shells can be degummed to extract fibers for use in textiles, papermaking or ship repair fillers. Ramie shells scraped from fresh ramie skins can be used to extract furfural, which is a refining solvent in the chemical industry and a resin plastic.

[0004] Ramie has a wide range of uses, a large planting area, and high yield. However, it is now seriously polluted and has a high content of heavy metals in the soil. The heavy metals in the soil can cause chlorophyll degradation, inhibit photosynthesis, and affect the quality of ramie. Therefore, providing a method for improving ramie's resistance to heavy metal stress is very important in the field of ramie planting technology. Summary of the invention

[0005] Based on the above content, the present invention provides a method for improving ramie's resistance to heavy metal stress.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a method for improving ramie's resistance to heavy metal stress, comprising the following steps:

[0008] Before transplanting ramie seedlings, spray citric acid solution on the soil surface until the soil surface is completely wet, then plow the soil;

[0009] Performing a first light treatment at the ramie seedling stage, wherein the first light treatment uses a mixed light source of red light, green light and blue light;

[0010] The second illumination treatment is carried out during the vigorous growth period of ramie, and the second illumination treatment adopts a mixed light source of red light and blue light.

[0011] The ramie seedling stage is the stage from transplanting to closing the row;

[0012] The vigorous growth period of ramie is from row closure to when 1 / 3 of the stem is black.

[0013] Furthermore, the mass concentration of the citric acid aqueous solution is 0.2-0.5%.

[0014] Furthermore, the tillage depth is 8-12 cm.

[0015] Furthermore, the first illumination treatment uses a mixed light source with a red light, a green light and a blue light intensity ratio of 1:1:1.

[0016] Furthermore, the illumination intensity of the first illumination treatment is 240-270 W / m 2 .

[0017] Furthermore, the first light treatment is carried out from 21:00 to 23:00 every day.

[0018] Furthermore, the second illumination treatment uses a mixed light source with a red light and a blue light intensity ratio of 1:1.

[0019] Furthermore, the illumination intensity of the second illumination treatment is 120-180 W / m 2 .

[0020] Furthermore, a second light treatment was performed from 21:00 to 23:00 every day.

[0021] The present invention discloses the following technical effects:

[0022] The method of the invention is simple, can avoid the quality reduction of ramie caused by heavy metal stress, and is suitable for promotion. DETAILED DESCRIPTION

[0023] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0024] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0025] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0026] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0027] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0028] The present invention provides a method for improving ramie's resistance to heavy metal stress, comprising the following steps:

[0029] Before transplanting ramie seedlings, spray citric acid solution on the soil surface until the soil surface is completely wet, then plow the soil;

[0030] Performing a first light treatment at the ramie seedling stage, wherein the first light treatment uses a mixed light source of red light, green light and blue light;

[0031] The second illumination treatment is carried out during the vigorous growth period of ramie, and the second illumination treatment adopts a mixed light source of red light and blue light.

[0032] In the present invention, the mass concentration of the citric acid aqueous solution is 0.2-0.5%.

[0033] If the concentration of the citric acid aqueous solution is too high, the soil acidity will increase, the soil pH will decrease, and the growth of ramie will be affected. If the concentration of the citric acid aqueous solution is too low, the heavy metals in the soil cannot be effectively chelated, and the subsequent risk of ramie being stressed by heavy metals will increase, which is not conducive to improving the quality of ramie.

[0034] In the present invention, the tillage depth is 8-12 cm.

[0035] Too much tillage depth will affect the chelating effect of citric acid on heavy metals, and too little tillage depth is not conducive to the growth of ramie seedlings. Therefore, the preferred tillage depth of the present invention is 8-12 cm, and the more preferred tillage depth is 10 cm.

[0036] In the present invention, the first illumination treatment uses a mixed light source with a red light, green light and blue light intensity ratio of 1:1:1. The illumination intensity of the first illumination treatment is 240-270W / m 2 The first light treatment is carried out from 21:00 to 23:00 every day.

[0037] Using a mixed light source of red, green and blue light during the ramie seedling stage can promote the secretion of ramie acid by the ramie roots. Ramie acid can chelate heavy metal ions such as cadmium and lead in the soil, thereby inhibiting the movement of heavy metals and reducing heavy metal stress. Light intensity ratios, light intensity and light exposure time exceeding the above records will affect the amount of ramie acid secreted by the ramie roots. After repeated experiments, the present invention determined that the first light treatment uses a mixed light source with a red, green and blue light intensity ratio of 1:1:1, and a light intensity of 240-270W / m 2 When the first light treatment was carried out between 21:00 and 23:00 every day, the ramie root system produced the highest content of ramie acid, and had the strongest inhibitory effect on heavy metal stress.

[0038] In the present invention, the second illumination treatment uses a mixed light source with a red light and a blue light intensity ratio of 1:1. The illumination intensity of the second illumination treatment is 120-180 W / m 2 The second light treatment was carried out from 21:00 to 23:00 every day.

[0039] Using a mixed light source of red and blue light for the second light treatment during the vigorous growth period of ramie can promote the content of hemicellulose in root cells. Hemicellulose has the function of binding heavy metal ions, thereby reducing heavy metal stress; while using other mixed light sources, such as a mixed light source of red and green light, the inhibitory effect on heavy metal stress is not as good as a mixed light source of red and blue light. Using a mixed light source of red and blue light at the same time, and limiting the above-mentioned light intensity ratio, light intensity and irradiation time, can also promote the production of protein, crude fat and fiber, and improve the quality of ramie.

[0040] The conventional ramie management methods described in the present invention are management methods such as watering and fertilizing that are well known in the art. They are not the focus of protection of the present invention and will not be described in detail here. They will not affect the understanding and implementation of the technical solution of the present invention by those skilled in the art.

[0041] The heavy metal content in the soil used for planting ramie in the embodiment of the present invention is 503.21±12.24 mg·kg -1 , cadmium 6.30±0.11mg·kg -1 .

[0042] The ramie in the embodiment of the present invention is Xiangzhu No. 3.

[0043] Example 1

[0044] Step 1: Before transplanting ramie seedlings, spray a 0.3% citric acid aqueous solution on the soil surface until the soil surface is completely moistened, and then plow the soil to a depth of 10 cm.

[0045] Step 2: Perform the first illumination treatment at the ramie seedling stage, using a mixed light source with a red light, green light and blue light intensity ratio of 1:1:1; the illumination intensity is 240W / m 2 , light treatment is carried out from 21:00 to 23:00 every day.

[0046] Step 3: Perform a second light treatment during the ramie growing season, using a mixed light source with a red light and blue light intensity ratio of 1:1 and a light intensity of 180W / m 2 , light treatment is carried out from 21:00 to 23:00 every day.

[0047] Step 4: Other watering, fertilizing, etc. refer to the conventional management methods for growing ramie in this field.

[0048] Example 2

[0049] Step 1, before transplanting ramie seedlings, spray the soil surface with a 0.5% citric acid aqueous solution until the soil surface is completely wetted, and then plow the soil to a depth of 10 cm;

[0050] Step 2: Perform the first illumination treatment at the ramie seedling stage, using a mixed light source with a red light, green light and blue light intensity ratio of 1:1:1; the illumination intensity is 270W / m 2 , light treatment is carried out from 21:00 to 23:00 every day.

[0051] Step 3: Perform a second light treatment during the ramie vigorous growth period, using a mixed light source with a red light and blue light intensity ratio of 1:1 and a light intensity of 120W / m 2 , light treatment is carried out from 21:00 to 23:00 every day.

[0052] Step 4: Other watering, fertilizing, etc. refer to the conventional management methods for growing ramie in this field.

[0053] Example 3

[0054] The only difference from Example 1 is that the concentration of the citric acid aqueous solution in step 1 is 0.2%.

[0055] Example 4

[0056] The only difference from Example 1 is that the step of spraying the citric acid aqueous solution in step 1 is omitted.

[0057] Example 5

[0058] The only difference from Example 1 is that the first light irradiation step in step 2 is omitted.

[0059] Example 6

[0060] The only difference from Example 1 is that the second light irradiation step in step 3 is omitted.

[0061] The quality of the ramie with mature fibers at the process maturity stage (from 1 / 3 of the black stalk to the stage when the black stalk is about 30 cm away from the tip) in Examples 1-6 was tested (the testing means are conventional technical means in the field, not the focus of protection of the present invention, and will not be repeated here), and the results are shown in Table 1.

[0062] Table 1

[0063] Crude Protein CP Crude fat EE Ash Crude fiber CF Example 1 26.73±0.06 7.93±0.09 20.04±0.43 31.84±0.71 Example 2 24.16±0.11 6.32±0.13 19.64±0.71 29.63±0.80 Example 3 25.92±0.13 7.16±0.17 18.93±0.31 30.81±0.99 Example 4 20.22±0.15 5.95±0.19 16.62±0.38 25.16±1.03 Example 5 18.39±0.09 5.38±0.28 15.38±0.52 23.76±1.42 Example 6 17.13±0.21 5.29±0.16 14.82±0.93 21.83±1.49

[0064] It can be seen from Table 1 that spraying citric acid aqueous solution before transplanting ramie seedlings and performing light treatment during the seedling and vigorous growth stages of ramie can effectively alleviate the reduction in ramie quality caused by heavy metal stress.

[0065] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for improving ramie's resistance to heavy metal stress, characterized in that: The following steps are involved: Before transplanting ramie seedlings, spray citric acid solution on the soil surface until the soil surface is completely wet, then plow the soil; Performing a first light treatment at the ramie seedling stage, wherein the first light treatment uses a mixed light source of red light, green light and blue light; The second illumination treatment is carried out during the vigorous growth period of ramie, and the second illumination treatment adopts a mixed light source of red light and blue light.

2. The method for improving ramie's resistance to heavy metal stress according to claim 1, characterized in that: The mass concentration of the citric acid aqueous solution is 0.2-0.5%.

3. The method for improving ramie's resistance to heavy metal stress according to claim 1, characterized in that: The tillage depth is 8-12 cm.

4. The method for improving ramie's resistance to heavy metal stress according to claim 1, characterized in that: The first illumination treatment uses a mixed light source with a red light, a green light and a blue light intensity ratio of 1:1:

1.

5. The method for improving ramie's resistance to heavy metal stress according to claim 1, characterized in that: The illumination intensity of the first illumination treatment is 240-270 W / m 2 .

6. The method for improving ramie's resistance to heavy metal stress according to claim 1, characterized in that: The first light treatment was carried out from 21:00 to 23:00 every day.

7. The method for improving ramie's resistance to heavy metal stress according to claim 1, characterized in that: The second illumination treatment uses a mixed light source with a red light and a blue light intensity ratio of 1:

1.

8. The method for improving ramie's resistance to heavy metal stress according to claim 1, characterized in that: The illumination intensity of the second illumination treatment is 120-180W / m 2 .

9. The method for improving ramie's resistance to heavy metal stress according to claim 1, characterized in that: The second light treatment was carried out from 21:00 to 23:00 every day.