CN115486283A - Application of exogenous Si in improvement of leaf vegetable quality under Cd stress - Google Patents

Abstract

The invention discloses application of exogenous Si in improving the quality index of leaf vegetables under Cd stress, and belongs to the field of vegetable planting safety. The application of the exogenous Si in improving the quality index of the leaf vegetables under the Cd stress promotes the normal growth of the leaf vegetables under the Cd stress, relieves the growth inhibition of the leaf vegetables, and increases the root length, the plant height, the dry weight and the fresh weight to different degrees. In addition, under the action of Si, the accumulation of Cd in the leaf vegetables under the stress of Cd can be reduced, the content of soluble sugar, soluble protein and vitamin C in the leaf vegetables can be increased, and the method has positive significance for safe production and improvement of nutritional value of the leaf vegetables.

Description

Application of Exogenous Si in Improving the Quality of Leafy Vegetables under Cd Stress

technical field

The invention belongs to the field of vegetable planting safety, in particular to the application of exogenous Si in improving the quality of leafy vegetables under Cd stress.

Background technique

Cd is a non-essential toxic heavy metal element for plant growth and development, and has the characteristics of being easily absorbed by plants, strong mobility, and difficult to degrade. However, excessive use of chemical fertilizers and pesticides, wastewater irrigation, and soil Cd pollution have become serious environmental problems worldwide due to the increase in mining activities. Cd interferes with the normal metabolic, physiological and biochemical processes of plants, resulting in growth inhibition, decreased photosynthetic rate, oxidative damage, metabolic disturbance, nutrient deficiency, and decreased yield and quality. In addition, Cd-contaminated crops pose a serious food safety problem and at the same time pose a threat to human health. Therefore, it is urgent to improve the Cd tolerance and reduce the Cd content of food crops.

Si is an essential beneficial mineral nutrient for plants. It not only plays a role in regulating the nutritional balance of plants, but also has the ability to protect plants from damage. It has been reported that Si can improve plant tolerance to Cd toxicity, mainly by reducing heavy metal uptake, reducing root-stem transport, and reducing lipid peroxidation to protect plants from heavy metal toxicity. In addition, a large number of studies have proved that Si can reduce the accumulation of heavy metals in crops such as rice, wheat, pea, tomato, and corn, and reduce the toxicity of heavy metals. At present, Si is mostly applied directly into the soil in the form of silicon fertilizer and silicon-based materials. Due to the poor solubility of such materials and easy adsorption and fixation by soil colloids, their utilization rate is low. In addition, the current research on Si on leafy vegetables is mostly focused on growth and development, heavy metal uptake and transport, anti-oxidation, and crop yield, and little is involved in the quality of leafy vegetables.

Leafy vegetables are the most common and important vegetable species grown worldwide. They are sensitive to heavy metal stress and easily absorb and accumulate heavy metals. Excessive heavy metals in leafy vegetables will not only lead to the decline of quality and yield, but also pose potential risks to human health.

Contents of the invention

The purpose of the present invention is to alleviate the growth inhibition and quality decline of leafy vegetables under Cd stress, and to provide the application of exogenous Si in improving the quality of leafy vegetables under Cd stress.

In order to achieve the above object, the present invention adopts the following technical solutions to achieve:

The application of exogenous Si in improving the quality of leafy vegetables under Cd stress is used to increase the content of soluble sugar, soluble protein and vitamin C in leafy vegetables under Cd stress.

Further, the exogenous donor of Si is Na ₂ SiO ₃ ·9H ₂ O aqueous solution.

Further, the concentration of the Na ₂ SiO ₃ ·9H ₂ O aqueous solution is 0.5 molL ⁻¹ .

Compared with the prior art, the present invention has the following beneficial effects:

The application of exogenous Si provided by the present invention in increasing the soluble sugar, soluble protein and vitamin C content in leafy vegetables under Cd stress, by adding exogenous Si, promotes the normal growth of rape and spinach under Cd stress, making rape The root length and plant height increased by 11.32% and 8.46%, respectively, and the root dry weight increased by 27.12%; the root length and plant height of spinach increased by 17.08% and 21.18%, respectively, and the fresh weight and dry weight increased in the leaves and roots, respectively. 161.17%, 117.15% and 55.72%, 21.79%. This is because Si can promote plant growth by stimulating the absorption and utilization of other nutrients; in addition, Si may also participate in cell elongation and cell division, which increases dry weight. In addition, the application of Si can also increase the content of soluble sugar, soluble protein and vitamin C in rapeseed and spinach, among which, compared with Cd treatment, the Cd content in leaves and roots decreased by 20.26% and 20.26% respectively in rapeseed and spinach. 27.54% and 36.91%, 23.60%; the content of soluble sugar and vitamin C increased significantly in rapeseed, increased by 14.72% and 7.29%, respectively, and the soluble protein in spinach increased by 58.19%. Because Si treatment can produce important plant hormone IAA, hormone IAA can actively regulate protein synthesis in plants, and at the same time, Si itself is an essential beneficial mineral nutrient for plants, which can improve the physiological state of plants and indirectly promote the accumulation of soluble proteins .

detailed description

In order to enable those skilled in the art to better understand the solution of the present invention, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the present invention Examples, but not all examples. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first" and "second" in the description and claims of the present invention are used to distinguish similar objects, but not necessarily used to describe a specific order or sequence. It should be understood that the data so used may be interchanged under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

Below in conjunction with attached table the present invention is described in further detail:

Example

Select seeds with uniform and plump seeds and sterilize them with 3% NaClO solution for 15-20 minutes, rinse the residual NaClO on the surface of the seeds several times with deionized water until it is odorless, spread the sterilized seeds evenly on the seedling trays with vermiculite A thin layer of vermiculite was sprinkled on the surface of the seeds, sealed with plastic wrap to avoid light germination, and cultivated in an artificial climate chamber. The ambient temperature light/dark is 26°C/20°C, the light/dark time is 14h/10h, and the relative humidity is (60-70)%. At the two-leaf and one-heart stage of the seedlings, move the seedlings to 1/4 of the improved Hoagland nutrient solution for two weeks, then select robust and consistent seedlings and culture them in 1/2 of the improved Hoagland nutrient solution for one week, and then use 0.5M Si solution (Na ₂ SiO ₃ ·9H ₂ O) and 3mg L ^-1 Cd solution (CdCl ₂ ·2.5H ₂ O) treated the seedlings that were continuously cultured in 1/2 improved Hoagland nutrient solution, and the pH of the culture solution was adjusted to The value was adjusted to 6.0, the nutrient solution was changed every three days, and the samples were collected after one week of treatment.

Rapeseed and spinach were treated as follows: (1) CK control group; (2) Cd treatment group; (3) Si treatment group; (4) Cd+Si treatment group. There were 8 treatment groups in total, each treatment group had six parallels, and samples were collected after 7 days of treatment.

The test result items are as follows:

1. Root length and plant height

Lay rapeseed and spinach plants flat on the table, and use a scale to measure their root length and plant height, respectively.

2. Fresh weight and dry weight

The rapeseed and spinach plants are divided into roots and leaves, and the fresh weights are weighed and recorded. After the roots are soaked in _0.05MEDTA -Na for 15-20min, the Cd attached to the surface of the roots is chelated, and then the roots are washed with deionized water and washed with filter paper. Blot dry. After weighing the fresh weight of each organ, place it in an oven at 105°C for 30 minutes, dry it at 80°C until it reaches a constant weight, weigh its dry weight and record it.

3. Determination of Cd content

Weigh 0.1 g of each dried sample and place it in a digestion tube, add 10 mL of concentrated _HNO3 , cover the digestion cap, and place it for 8 hours. Digest at 80°C and 120°C for 1.5h, at 150°C for 3h, and at 175°C to remove the acid to 1mL. After the digestion solution is cooled, transfer it to a 10mL volumetric flask and dilute to volume with 2% _HNO3 . Then filter with a 0.22 μm filter head, and the filtrate is set aside. The Cd content was determined by atomic absorption spectrometer.

4. Determination of quality indicators (soluble sugar, soluble protein, vitamin C)

(1) Determination of soluble sugar content

The soluble sugar content was determined by the anthrone method. Take 0.2g of fresh plant leaves and put them into a graduated test tube, add 5-10mL of distilled water, and extract in boiling water for 30min (a total of two extractions). After cooling, filter it into a 25mL volumetric flask, rinse the test tube repeatedly with distilled water and make it to volume. Draw 0.5mL extract into a test tube, add 1.5mL distilled water, then add 0.5mL anthrone ethyl acetate solution and 5mL concentrated sulfuric acid in sequence, shake fully, heat immediately in a boiling water bath, and keep warm for 1min accurately, take it out and cool to At room temperature, the absorbance was measured at a wavelength of 630nm.

(2) Determination of soluble protein content

The content of soluble protein was measured by Coomassie Brilliant Blue G-250 method. Take 0.2g of fresh plant leaves, add 8mL of distilled water to grind into a homogenate, and place it at room temperature (20-25°C) for 0.5-1.0h to fully extract. Then, centrifuge at 4000r/min for 20min at 4°C, transfer the supernatant into a 10mL volumetric flask, and distill it to volume. Take 0.5mL of the extract into a 10ml stoppered colorimetric tube, add 5mL of Coomassie Brilliant Blue reagent, mix well, let it stand for 2min, and use the blank as a control, quickly measure the absorbance at a wavelength of 595nm.

(3) Determination of vitamin C content

The content of vitamin C was measured by the bipyridine method. Take 0.2 g of fresh plant leaves, add 4 mL of 6% TCA to grind into a homogenate, and then centrifuge at 8000 r/min for 10 min at 4°C. Add 0.8mL 0.2 mol L ^-1 PBS (pH 7.4), 0.2mL supernatant, 1.0mL 10% TCA, 0.8mL 42% H ₃ P0 ₄ , 0.8mL 2% 2,2-bipyridine and 0.4 mL 3% FeCl ₃ , after mixing evenly, react in a water bath at 42°C for 60min, and then measure the absorbance at a wavelength of 525nm.

5. Data processing

Excel data processing software was used for data sorting, and SPSS20.0 was used for one-way analysis of variance (p<0.05), and all data were the average values of six experiments.

Table 1 shows the root length and plant height of rapeseed and spinach under different treatments. As shown in Table 1, the root length and plant height of rapeseed and spinach were inhibited under Cd stress, while the addition of exogenous Si could significantly increase the root length and plant height of rapeseed and spinach under Cd stress (p<0.05). Among them, compared with CK, the root length of rapeseed under Cd stress decreased by 20.45%, the root length and plant height of spinach decreased significantly by 8.84% and 18.86%; compared with Cd treatment, the root length and plant height of rapeseed after adding exogenous Si The height increased by 11.32% and 8.46% respectively, and the root length and plant height of spinach increased by 17.08% and 21.18% respectively. Therefore, under the action of exogenous Si, the root damage of leafy vegetables caused by Cd stress was alleviated, and the growth inhibition was relieved.

Table 1 Root length and plant height of rapeseed and spinach under different treatments

Table 2 shows the fresh weight and dry weight of different parts of rapeseed and spinach under different treatments. It can be seen from Table 2 that the fresh weight and dry weight of each organ of rapeseed and spinach decreased in different degrees under Cd stress (p<0.05). Compared with CK, the fresh weight of leaves and roots of rapeseed decreased by 18.32% after Cd treatment and 26.88%, the root dry weight decreased by 25.18%, and the leaf dry weight had no obvious change; the fresh weight and dry weight of spinach leaves decreased by 60.52% and 58.09%, respectively, and the fresh and dry weight of roots decreased by 32.29% and 22.84% . The fresh weight and dry weight of spinach under Cd stress after exogenous Si treatment increased by 161.17%, 117.15%, 55.72%, and 21.79% in the leaves and roots, respectively; Variety. This may be because Si will participate in the process of cell elongation and cell division, thereby increasing the biomass of leafy vegetables.

Table 2 Fresh weight and dry weight of different parts of rapeseed and spinach under different treatments

Table 3 shows the Cd content in rapeseed and spinach under different treatments. It can be seen from Table 3 that compared with Cd treatment, exogenous addition of Si can significantly reduce the accumulation of Cd in different parts of the two leafy vegetables (p<0.05). Cd content in rapeseed and spinach decreased by 20.26%, 27.54% and 36.91%, 23.60%, respectively. Among them, the accumulation of Cd in rapeseed is more obvious than that in spinach, indicating that rapeseed has a stronger ability to enrich Cd. Exogenous Si can reduce Cd toxicity and enhance Cd resistance by regulating the absorption and transport of Cd. distribution and accumulation in leafy vegetables, thereby alleviating the toxic effect of Cd.

Table 3 Cd content in different parts of rapeseed and spinach under different treatments

Table 4 shows the content of different quality indicators in rapeseed and spinach under different treatments. As shown in Table 4, compared with the CK control, the content of soluble protein and vitamin C in rapeseed under Cd stress decreased by 12.34% and 17.10%, respectively; the soluble protein in spinach decreased by 39.57% (p<0.05). The content of soluble sugar and vitamin C in rapeseed increased significantly after adding Si exogenously, by 14.72% and 7.29% respectively; the soluble protein in spinach increased by 58.19%. It indicated that Si could increase the content of quality indexes of leafy vegetables under Cd stress to a certain extent, and improve the nutritional value of leafy vegetables.

Table 4 Contents of different quality indicators of rapeseed and spinach under different treatments

The above content is only to illustrate the technical idea of the present invention, and cannot limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed in the present invention, all fall into the scope of the claims of the present invention. within the scope of protection.

Claims (3)

1. The application of the exogenous Si in improving the quality of the leafy vegetables under the Cd stress is characterized by being used for improving the content of soluble sugar, soluble protein and vitamin C in the leafy vegetables under the Cd stress.

2. The use of exogenous Si according to claim 1 for improving the quality of leafy vegetables under Cd stress, wherein the exogenous donor of Si is Na ₂ SiO ₃ ·9H ₂ And (4) O aqueous solution.

3. The application of exogenous Si in improving the quality of leafy vegetables under Cd stress according to claim 2, wherein Na is ₂ SiO ₃ ·9H ₂ The concentration of the O aqueous solution was 0.5mol L ^-1 。