Illumination culture method and planting method for improving salt tolerance of rice

Abstract

The invention provides an illumination culture method and a planting method for improving salt tolerance of rice. According to the illumination culture method for improving the salt tolerance of the rice, an artificial light source is adopted to irradiate rice seedlings, the light supply mode of the artificial light source is that white light and far-red light illuminate at the same time, the light quantum flux density of the white light is 350-450 [mu] mol.m <-2 >. S <-1 >, the illumination time is 10-12 h / d, the light quantum flux density of the far-red light (the wavelength is 700-750 nm) is 450-550 [mu] mol.m <-2 >. S <-1 >, and the illumination time is 10-12 h / d. In the growth period of rice seedlings, far-red light illumination is increased on the basis of conventional white light, the number of rice leaves under salt stress is increased, and the leaf area is increased; the activity of antioxidant enzyme is increased, and active oxygen damage is relieved; plant photosynthesis is promoted, and dry matter accumulation is improved; the tillering number is increased, and rice yield increase is promoted.

Description

Technical Field

[0001] This application belongs to the technical field of rice cultivation, and specifically relates to a light cultivation method and a planting method for improving the salt tolerance of rice. Background Art

[0002] Soil salinization is a widespread soil degradation process on the earth, threatening global soil resources and having an important impact on the improvement of crop yield and quality. Therefore, in order to ensure food security, improving the salt tolerance of crops has received extensive attention. At present, different strategies including arbuscular mycorrhizal fungi, plant growth-promoting rhizobacteria, exogenous growth regulators, and nanoparticles have been adopted to improve the salt tolerance of crops. However, the high cost, harm to organisms, and / or operational difficulties of these methods limit their wide application. Therefore, there is an urgent need to develop adaptable and economical strategies to enhance the tolerance of crops to salt stress.

[0003] The first response of plants to salt stress is the decline of photosynthetic capacity. The weakening of photosynthesis leads to the excessive accumulation of reactive oxygen species such as superoxide anion, hydroxyl radical, and hydrogen peroxide in plant cells, which in turn directly damages proteins, lipids, and nucleic acids, resulting in cell death, leaf senescence, and growth inhibition. Therefore, there is an urgent need to develop a cultivation method that can promote the salt tolerance and increase the yield of rice. Summary of the Invention

[0004] Aiming at the problems in this field, in order to alleviate the inhibitory effect of salt stress on the growth, development, and yield of rice, this application provides a light cultivation method and a planting method for improving the salt tolerance of rice.

[0005] The technical solution of this application is as follows:

[0006] A light cultivation method for improving the salt tolerance of rice, irradiating rice seedlings with an artificial light source, the light supply mode of the artificial light source is simultaneous illumination with white light and far-red light, the photon flux density of the white light is 350 - 450 μmol·m -2 ·s -1 , the illumination time is 10 - 12 h / d, the photon flux density of the far-red light is 450 - 550 μmol·m -2 ·s -1 , and the illumination time is 10 - 12 h / d.

[0007] Furthermore, the wavelength of the far-red light is 700 - 750 nm.

[0008] Furthermore, the time for irradiating the rice seedlings is 8:00 - 20:00.

[0009] Furthermore, the light cultivation period of the rice seedlings is 20 - 25 days.

[0010] Furthermore, during the day (8:00 to 20:00) of light cultivation, the temperature is 25 - 35°C, and during the night (20:00 to 8:00 the next day), the temperature is 18 - 25°C.

[0011] Furthermore, during the day of light cultivation, the temperature is 28 - 32°C, and during the night, the temperature is 20 - 22°C.

[0012] Furthermore, the light cultivation method includes the following steps:

[0013] (1) Raising seedlings in a greenhouse,

[0014] After soaking and germinating rice seeds, raise seedlings in a greenhouse. When the first leaf of the rice emerges, light cultivation can begin;

[0015] (2) Light cultivation,

[0016] Irradiate the rice seedlings with the artificial light source. The light supply mode of the artificial light source is simultaneous illumination with the white light and the far - red light. The photon flux density of the white light is 350 - 450 μmol·m -2 ·s -1 , the light duration is 10 - 12 h / d, the photon flux density of the far - red light is 450 - 550 μmol·m -2 ·s -1 , the light duration is 10 - 12 h / d. When the fifth leaf of the rice emerges, the seedlings can be transplanted.

[0017] Furthermore, during the day in step (1), the temperature is 25 - 35°C, and during the night, the temperature is 18 - 25°C.

[0018] A planting method for improving the salt tolerance of rice includes any of the above - mentioned light cultivation methods for improving the salt tolerance of rice.

[0019] Furthermore, after light cultivation, transplant the seedlings into saline - alkali land where the soil salt content does not exceed 0.4%.

[0020] The beneficial effects of this application are as follows:

[0021] First, the far - red light in this application is beneficial to the photosynthesis of rice under specific conditions. This application can enhance the photochemical efficiency and thus increase the photosynthetic rate through the combined action of far - red light and short - wave photons.

[0022] Second, during the growth period of rice seedlings, adding far - red light illumination on the basis of conventional white light is beneficial to increasing the number of rice leaves and leaf area under salt stress; increasing the activity of antioxidant enzymes to reduce active oxygen damage; promoting plant photosynthesis and increasing dry matter accumulation; increasing the tiller number and promoting the yield increase of rice.

[0023] Third, the light illumination method of the present application is optimized, with convenient operation, prominent advantages and high practicability.

[0024] Fourth, the planting method of the present application optimizes the rice planting method, which can promote the salt tolerance and yield increase of rice, and has broad application space and market prospects in modern agricultural production. Specific Embodiments

[0025] The following will describe the solution of the present application in detail in conjunction with specific embodiments. The following specific embodiments are only used to illustrate the present application and should not be regarded as limiting the scope of the present application. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer.

[0026] A light illumination cultivation method for improving the salt tolerance of rice includes the following steps:

[0027] (1) Greenhouse seedling raising,

[0028] After the rice seeds are soaked and germinated, greenhouse seedling raising is carried out. The daytime temperature can be 30°C and the nighttime temperature can be 25°C. When the first leaf of the rice extends, light illumination cultivation can begin.

[0029] (2) Light illumination cultivation,

[0030] The rice seedlings are irradiated with artificial light sources during the period from 8:00 to 20:00. The light supply mode of the artificial light source is simultaneous illumination with white light and far-red light. The photon flux density of the white light is 350 - 450 μmol·m -2 ·s -1 , and the light illumination time is 10 - 12 h / d. The wavelength of the far-red light can be 700 - 800 nm, preferably 700 - 750 nm. The photon flux density of the far-red light is 450 - 550 μmol·m -2 ·s -1 , and the light illumination time is 10 - 12 h / d. If the photon flux density of the far-red light is too low, it may inhibit the height of rice seedlings, weaken the photosynthetic ability and stress resistance; if the photon flux density is too high, it is easy to cause the overgrowth of rice seedlings, the decline of stress resistance and the reduction of yield potential. The light illumination cultivation period is 20 - 25 days. The daytime (8:00 to 20:00) temperature during light illumination cultivation is 25 - 35°C, preferably 28 - 32°C, and the nighttime (20:00 to 8:00 the next day) temperature is 18 - 25°C, preferably 20 - 22°C.

[0031] A planting method for improving the salt tolerance of rice includes the above-mentioned light illumination cultivation method for improving the salt tolerance of rice. After light illumination cultivation, the rice seedlings are transplanted into saline-alkali land, and the soil salt content should not exceed 0.4%.

[0032] Example 1

[0033] Taking the rice variety Nanjing 9108 as a sample, the soil was taken from the plough layer of the farm paddy field. The soil pH, organic matter, and nitrogen, phosphorus, and potassium contents were measured. The soil was filled into plastic buckets, and the weight of the soil in each bucket was calculated. According to the salt content designed in the experiment and the weight of the soil, the weight of NaCl sea salt was calculated. The dry salt was dissolved in water, and the solution was evenly mixed into the seedling trays and soaked with water three times.

[0034] Rice seeds of the same specification were transplanted into the seedling trays (the salt stress concentration of the nutrient soil in the seedling trays was 0.2%), and then transferred to an artificial climate greenhouse. They were divided into two groups. The first group was only irradiated with conventional white light, and the second group was irradiated with conventional white light plus far-red light. The light environment parameters were set as follows: the photon flux density of the conventional white light was 400 μmol·m -2 ·s -1 , the light duration (8:00 - 20:00) was 12 h / d; the wavelength of the far-red light was 700 nm, and the photon flux density of the far-red light irradiation was 500 μmol·m -2 ·s -1 , the light duration (8:00 - 20:00) was 12 h / d. The temperature was set to 30 °C during the day (from 8 am to 8 pm) and 25 °C at night (from 8 pm to 8 am the next day).

[0035] 1. Effects of white light + far-red light irradiation on the leaf number and morphology of salt-stressed rice.

[0036] After growing for 20 days under the above two light conditions, the morphology of the rice was observed, as shown in Table 1.

[0037] Table 1

[0038]

[0039] The results showed that, as can be seen from Table 1, compared with the conventional white light, when irradiated with conventional white light + far-red light, the number of leaves of rice seedlings increased significantly, with an increase rate of 14.3%. Compared with the conventional white light, the combination of white light + far-red light irradiation significantly increased the leaf lengths of the second and third fully expanded leaves of rice seedlings, with increase rates of 9.1% and 6.3% respectively. This result indicates that the light cultivation method of this application can promote the growth process of rice under salt stress, increase the leaf number and leaf area.

[0040] 2. Effects of white light + far-red light irradiation on the antioxidant enzyme activities of salt-stressed rice leaves.

[0041] After growing for 20 days under the above two light conditions, the effects of white light + far-red light irradiation on the antioxidant enzyme activities of rice leaves were measured, as shown in Table 2.

[0042] Table 2

[0043]

[0044] The results showed that, as can be seen from Table 2, compared with conventional white light, the activities of superoxide dismutase, catalase and ascorbate peroxidase in the leaves of rice seedlings were significantly increased under conventional white light + far-red light irradiation, with the increase rates reaching 22.5%, 37.8% and 12.9% respectively. This result indicates that the light cultivation method of this application can increase the activities of antioxidant enzymes in salt-stressed rice seedlings to reduce the damage of reactive oxygen species to rice leaves under salt stress.

[0045] 3. Effects of white light + far-red light irradiation on photosynthetic characteristics and dry matter weight of salt-stressed rice leaves.

[0046] After growing for 20 days under the above two light conditions, the effects of white light + far-red light irradiation on the photosynthetic characteristics and dry matter weight of rice leaves were measured, as shown in Table 3.

[0047] Table 3

[0048]

[0049] The results showed that, as can be seen from Table 3, compared with conventional white light, the photosynthetic rate of the leaves of rice seedlings was significantly increased under conventional white light + far-red light irradiation, with an increase rate of 14.6%; the dry matter weight of the rice seedling plants was also significantly increased under conventional white light + far-red light irradiation, with an increase rate of 18.6%. This result indicates that the light cultivation method of this application promotes photosynthesis in salt-stressed rice leaves and increases dry matter accumulation.

[0050] 4. Effects of white light + far-red light irradiation on the tiller number and yield of salt-stressed rice.

[0051] After growing for 20 days under the above two light conditions, the rice seedlings were transplanted into coastal saline-alkali land (soil salt content 0.2% - 0.4%), and the effects of white light + far-red light irradiation on the tiller number and yield of rice population in coastal saline-alkali land were measured, as shown in Table 4.

[0052] Table 4

[0053]

[0054] The results showed that, as can be seen from Table 4, compared with conventional white light, the tiller number of the rice population at the jointing stage, heading stage and maturity stage was significantly increased under conventional white light + far-red light irradiation. In addition, the rice yield was also significantly increased under conventional white light + far-red light irradiation, with an increase rate of 11.0%. This result indicates that the light cultivation method of this application can increase the tiller number of the rice population at the key growth stages and promote rice yield increase.

[0055] Although the present application has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made thereto based on the present application, which will be obvious to those skilled in the art.

Claims

1. A light culture method for improving the salt tolerance of rice, characterized in that: The rice seedlings are irradiated with an artificial light source, wherein the light supply mode of the artificial light source is white light and far-infrared light at the same time, and the photon flux density of the white light is 350-450 μmol·m -2 ·s -1 The illumination time is 10-12 h / d, and the photon flux density of the far-infrared light is 450-550 μmol·m -2 ·s -1 , the lighting time is 10 to 12 h / d.

2. A light culture method for improving salt tolerance of rice according to claim 1, characterized in that: The wavelength of the far-infrared light is 700-750nm.

3. The method for improving the salt tolerance of rice according to claim 1, characterized in that: The rice seedlings are irradiated from 8:00 to 20:

00.

4. The method for improving the salt tolerance of rice according to claim 1, characterized in that: The light culture period of the rice seedlings is 20 to 25 days.

5. The method for improving the salt tolerance of rice according to claim 1, characterized in that: The daytime temperature for light culture is 25-35℃, and the nighttime temperature is 18-25℃.

6. The method for improving the salt tolerance of rice by illumination culture according to claim 5, characterized in that: The daytime temperature for light culture is 28-32°C, and the nighttime temperature is 20-22°C.

7. The method for improving the salt tolerance of rice according to claim 1, characterized in that: The steps include: (1) Greenhouse seedling cultivation, After soaking and germinating the rice seeds, they are raised in a greenhouse, and when the first rice leaf stretches out, light cultivation can begin; (2) Light culture, The rice seedlings are irradiated with the artificial light source, wherein the light supply mode of the artificial light source is simultaneous illumination of the white light and the far-infrared light, and the photon flux density of the white light is 350-450 μmol·m -2 ·s -1 The illumination time is 10-12 h / d, and the photon flux density of the far-infrared light is 450-550 μmol·m -2 ·s -1 The lighting time is 10 to 12 h / d. When the fifth leaf of the rice stretches out, the seedlings can be transplanted.

8. The method for improving the salt tolerance of rice by illumination culture according to claim 7, characterized in that: Step (1) The daytime temperature is 25-35°C, and the nighttime temperature is 18-25°C.

9. A planting method for improving salt tolerance of rice, characterized in that: The invention comprises the illumination culture method for improving the salt tolerance of rice as described in any one of claims 1 to 8.

10. A planting method for improving salt tolerance of rice according to claim 9, characterized in that: After light cultivation, the seedlings are planted in saline-alkali land, and the salt content of the soil does not exceed 0.4%.

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