Method for overcoming low temperature and weak light stress on pepper seedlings

Abstract

The present application relates to a method for overcoming low temperature and weak light stress of pepper seedlings, characterized in that water control is started at the three-leaf-one-heart stage of the pepper seedlings, and a urea solution is sprayed every day during the water control. The method of adversity training combined with spraying urea solution adopted by the present application improves the stress resistance of the pepper seedlings, completely overcomes the adverse effects of low temperature and weak light stress on the pepper seedlings in the later period, and the present application is simple in operation, suitable for application in production, and has high application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of agricultural planting technology, and particularly relates to a method for overcoming low-temperature and weak-light stress of pepper seedlings. BACKGROUND

[0002] Pepper is the largest vegetable in planting area in China, and is sensitive to low temperature and weak light. When the temperature is lower than 15 DEG C or the light intensity is lower than 200 mu m*m −2 ·s −1 , the growth and development of pepper will be inhibited, and the yield will be reduced. In recent years, due to the influence of frequent cloudy and rainy weather and extreme low temperature weather, the probability of low-temperature and weak-light stress in pepper seedling production increases, resulting in weak seedlings and diseases, and the yield and quality are reduced, which seriously restricts the efficient cultivation and off-season production of pepper. Therefore, solving the key problem of overcoming low-temperature and weak-light stress in pepper seedling production helps to improve the yield and quality of pepper harvest.

[0003] Stress training refers to that the plant shows strong resistance to the stress after the previous moderate stress treatment, and is also called stress memory. Compared with the plant without training, the signal regulation material, secondary metabolite and stress protective material of the trained plant can respond to the stress more quickly and effectively, so that the stress resistance of the plant is enhanced. At present, the application of stress training in production is rare, and the only application is mainly concentrated in field crops, and the application in pepper seedling is almost blank. SUMMARY

[0004] The purpose of the present application is to provide a method for overcoming low-temperature and weak-light stress of pepper seedlings, so as to solve the technical problems existing in the pepper seedling.

[0005] To this end, the technical scheme adopted by the present application is: a method for overcoming low-temperature and weak-light stress of pepper seedlings, water is controlled during the three-leaf one-heart period of pepper seedlings, and urea solution is sprayed every day during the water control period.

[0006] Further, the water content of the substrate is controlled to be 65%-75% of the maximum water holding capacity, and the urea solution with a mass fraction of 1.39%-1.50% is sprayed every day during the water control period, and the water control time is 5 days.

[0007] Further, the water content of the substrate is controlled to be 70% of the maximum water holding capacity, and the urea solution with a mass fraction of 1.50% is sprayed every day during the water control period.

[0008] Further, when the urea solution is sprayed, it is uniformly sprayed until the water drops on the leaf tip.

[0009] Further, the pepper variety used is one of Yangjiao No. 2, Yangjiao No. 5 and Yangjiao 1766.

[0010] Further, the substrate used for pepper seedling raising has the following physical and chemical properties: available nitrogen: 600-2000 mg / kg; available phosphorus: 400-1500 mg / kg; available potassium: 5000-10000 mg / kg; bulk density: 0.35-0.60 g / cm 3 ; total porosity: 70.00-76.00 %; organic matter content: 24.00-32.00 %; pH value: 5.8-6.6; EC value: 1100-1600 us / cm.

[0011] Further, the seedling hole disc used is a 50-hole standard hole disc.

[0012] Further, water control treatment is started at the three-leaf-one-heart stage of the pepper seedlings, the water content of the substrate is controlled to be 65-75% of the maximum water holding capacity, and a urea solution with a mass fraction of 1.39%-1.50% is sprayed every day during the water control period, the water control period is 5 days, and after the water control is over, the substrate is restored to the maximum water holding capacity for 3 days.

[0013] Further, after the restoration is over, low-temperature weak light treatment [T, temperature is 15℃ / 5℃ (day / night), light intensity is 100 μmol·m −2 ·s −1 , photoperiod is 12 h / 12 h (day / night)] is carried out, after the temperature and light treatment is over, the growth index and the strong seedling index are determined, wherein the strong seedling index = (stem diameter / plant height + underground dry weight / aboveground dry weight) x plant dry weight.

[0014] The advantage of the present application is that the present application adopts the method of adversity training combined with spraying urea solution to improve the stress resistance of pepper seedlings, completely overcomes the adverse effects of low-temperature weak light stress on pepper seedlings that may occur in the later period, and the present application is simple in operation, suitable for application in production, and has high application value. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a graph showing the performance of the net photosynthetic rate of the top leaf in Example 1.

[0016] Figure 2 It is a graph showing the correlation analysis of the strong seedling index of the pepper seedlings and the net photosynthetic rate of the top leaf in Example 1.

[0017] Figure 3 It is the performance of the net photosynthetic rate of the top leaf in Example 2.

[0018] Figure 4 It is a graph showing the correlation analysis of the strong seedling index of the pepper seedlings and the net photosynthetic rate of the top leaf in Example 2.

[0019] Figure 5Figure 2 shows the seedling index of the pepper seedlings treated with the urea solution of different concentrations in Example 2. DETAILED DESCRIPTION Example 1

[0020] With Yangjiao No. 5 as the material, seedling raising was carried out in a seedling raising greenhouse of Huaisi vegetable basket base in Yangzhou urban area in February 2022. The seedling raising method was conventional plug seedling raising. Different water control treatments were started at the three-leaf-one-heart stage of pepper seedlings (about 28 days after sowing, the number of days affected by changes in the environment in the greenhouse will be slightly different). The substrate water content was controlled at 65%-75% of the maximum water holding capacity. The water control method can be to supplement water after weighing or to supplement water according to the determination results of the soil water meter. Water control for 5 days. After the end of water control, the substrate was restored to the maximum water holding capacity (100%) for 3 days. After the end of restoration, low temperature and weak light treatment [T, temperature 15℃ / 5℃ (day / night), light intensity 100 μmol·m −2 ·s −1 , photoperiod 12 h / 12 h (day / night)] (this condition is the general treatment of low temperature and weak light stress of pepper) and normal temperature and light [CK, temperature 25℃ / 15℃ (day / night), light intensity 300 μmol·m −2 ·s −1 , photoperiod 12 h / 12 h (day / night)] (this condition is the general treatment of normal temperature and light of pepper) as the control. After the end of temperature and light treatment, the growth index and seedling index were determined, wherein the seedling index = (stem diameter / plant height + underground dry weight / aboveground dry weight) x plant dry weight. The results are shown in Table 1.

[0021] It can be seen that under low temperature and weak light treatment, with the decrease of substrate water content, the growth index and seedling index of pepper seedlings showed a trend of first increasing and then decreasing, indicating that moderate water control can improve the resistance of pepper seedlings and is beneficial to alleviate the decrease of pepper seedling index under low temperature and weak light treatment. Among them, the effect of 70% of the maximum water holding capacity of the substrate is the best. However, as can be seen from the table, moderate water control still cannot completely overcome low temperature and weak light stress, and further combination with other treatments is still needed (it should be noted that for those skilled in the art, the results shown in Table 1 are the results of one seedling raising, even if seedling raising is carried out in the same plot according to the same treatment method, due to the fact that the seedling raising conditions cannot be absolutely consistent in a strict sense, therefore, the results of each seedling raising will be different, but this does not affect the embodiment of the technical effect of Table 1 on different treatment methods).

[0022] Table 1 Performance of growth index and seedling index

[0023] Further, we measured the net photosynthetic rate of the top leaves of pepper seedlings under different treatments. It can be seen that under low temperature and weak light treatment, with the decrease of substrate water content, the net photosynthetic rate of the top leaves of pepper seedlings showed a trend of first rising and then falling, indicating that moderate water control can improve the photosynthetic capacity of pepper seedling leaves, and the effect of 70% substrate maximum water content treatment is the best.

[0024] In addition, the correlation analysis showed that the seedling index of pepper seedlings was significantly positively correlated with the net photosynthetic rate of the top leaves (the determination coefficient reached 0.8853), indicating that moderate water control can maintain a strong photosynthetic capacity of pepper seedlings to alleviate the decrease of seedling index under low temperature and weak light stress.

[0025] Implementation:2:

[0026] Further, with Yangjiao No. 5 as the material, seedling raising was carried out in the seedling raising greenhouse of Huaisi vegetable basket base in Yangzhou urban area in April 2022, and the seedling raising method was conventional plug seedling. The water control treatment was started at the three-leaf-one-heart stage of pepper seedlings (about 28 days after sowing, the number of days affected by changes in environmental factors in the greenhouse will be slightly different). Under the condition of 70% substrate maximum water holding capacity, different concentrations of urea solution were sprayed every day during the water control period, and the spraying was carried out at about 17:00, and the spraying was uniform until the leaf tip dripped water. The water control lasted for 5 days. After the water control, the substrate maximum water holding capacity was restored for 3 days. After the restoration, low temperature and weak light treatment [T, temperature 15 ℃ / 5 ℃ (day / night), light intensity 100 μmol·m −2 ·s −1 , photoperiod 12 h / 12 h (day / night)] was carried out, and normal temperature and light [CK, temperature 25 ℃ / 15 ℃ (day / night), light intensity 300 μmol·m −2 ·s −1 , photoperiod 12 h / 12 h (day / night)] was used as the control. After the temperature and light treatment, the growth indexes and seedling indexes were measured, and the results are shown in Table 2.

[0027] It can be seen that under low temperature and weak light treatment, with the increase of urea solution spraying concentration, the growth indexes and seedling indexes of pepper seedlings showed a trend of first rising and then falling, and the effect of 1.5% urea concentration treatment was the best. At the same time, under this treatment, the growth indexes and seedling indexes were greater than those under normal temperature and light treatment, indicating that using 70% substrate maximum water holding capacity for water control and spraying 1.5% urea solution can completely overcome the adverse effects of low temperature and weak light stress on pepper seedlings, and achieve the normal growth state of pepper seedlings.

[0028] Table 2 Growth index and seedling index table

[0029] Further, we measured the net photosynthetic rate of the top leaves of the pepper seedlings, and found that the net photosynthetic rate of the top leaves of the pepper seedlings increased first and then decreased with the increase of the urea solution spraying concentration under low temperature and weak light treatment, indicating that spraying appropriate concentration of urea can improve the photosynthetic capacity of the pepper seedling leaves, and the effect of 1.5% urea concentration treatment is the best.

[0030] In addition, the correlation analysis showed that the seedling index of the pepper seedlings was extremely significantly positively correlated with the net photosynthetic rate of the top leaves (the determination coefficient reached 0.9672), indicating that under the condition, spraying appropriate concentration of urea solution can improve the photosynthetic capacity of the seedlings, thereby improving the seedling index.

[0031] Further, we fitted the data with the urea solution spraying concentration as the horizontal coordinate and the seedling index as the vertical coordinate, and found that the seedling index showed a trend of monomial fourth power equation with the urea solution spraying concentration, and the equation was y = 149765x 4 -9824.7x 3 + 161.04x 2 - 0.0971x + 0.0551, the determination coefficient R² = 0.9361 reached a significant level. We put the seedling index of the control treatment (CK+0%) into the equation, and obtained the corresponding urea solution spraying concentration of 1.3875%. Therefore, by controlling the urea solution spraying concentration between 1.39%-1.50%, the seedling index can reach or exceed the seedling index of the control treatment (CK+0%).

Claims

1. A method for overcoming low temperature and low light stress of pepper seedlings, characterized in that, Water control was started at the three-leaf stage, and urea solution was sprayed every day during the water control period; Water control was started at the three-leaf stage, and urea solution with a mass fraction of 1.50% was sprayed every day during the water control period; Water control was performed for 5 days, and then the substrate was restored to the maximum water holding capacity for 3 days; After the recovery, low temperature and weak light treatment [T, temperature is 15℃ / 5℃ (day / night), light intensity is 100 μmol·m -2 ·s -1 , photoperiod is 12h / 12h (day / night)] was carried out, after the end of the temperature and light treatment, growth index and seedling index were determined, wherein the seedling index = (stem diameter / plant height + underground dry weight / aboveground dry weight) x plant dry weight; The concentration of urea solution sprayed showed a monadic quartic equation trend, the equation was y=149765x 4 -9824.7x 3 +161.04x 2 -0.0971x+0.0551, the determination coefficient R²=0.9361 reached a significant level.

2. The method for overcoming low temperature and weak light stress of pepper seedlings according to claim 1, characterized in that, When the urea solution was sprayed, it was sprayed evenly until water dripped from the leaf tips.

3. The method of claim 1, wherein the method is characterized by, The pepper varieties used were one of Yangjiao No. 2, Yangjiao No. 5, and Yangjiao 1766.

4. The method of claim 1, wherein the method is characterized by, The substrate used for pepper seedling culture had the following physicochemical properties: available nitrogen: 600-2000 mg / kg; available phosphorus: 400-1500 mg / kg; available potassium: 5000-10000 mg / kg; total porosity: 70.00-76.00%; organic matter content: 24.00-32.00%; pH value: 5.8-6.6; EC value: 1100-1600 us / cm. Bulk density: 0.35-0.60 g / cm 3 ; The seedling hole tray used was a 50-hole standard hole tray.

5. The method of claim 1, wherein the method is characterized by, ​

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