Effect of Drought Resistance and Water Retention Agent on Drought Resistance of Turfgrass

From: SOCO
publisher: Anthony
Time: 2020-09-16
Summary: Compared with the water-retaining agent, the SOD, CAT, POD activity, Pro content and root vigor were significantly increased after the water-retaining agent was added, and the MDA content and the relative conductivity of the leaf were significantly reduced.
Drought-resistant and water-retaining agent is a kind of high-efficiency water-absorbing resin. After being applied to the soil, it can quickly absorb and retain water equivalent to one hundred or even thousand times its own weight and form a gel. The water is not easy to precipitate, and it has good water absorption and water retention properties. Good stability and reversibility, and can be reused many times. Due to the special chemical composition, physical structure and water absorption properties of water-retaining agents, they are widely used in industry, agriculture, medicine and other fields, but they are rarely used on turfgrass, and most of the research is about the emergence and growth of seedlings. There have been reports on the relationship between turfgrass and temperature, drought stress, different substrates and different salt concentrations. It has been found that turfgrass has a certain resistance to stress, and this ability can vary with the intensity of stress and the changes of turfgrass varieties. . In view of the poor resistance of turfgrass and serious water consumption, this study explored the effects of water-retaining agents on the drought resistance of turfgrass through experiments, hoping to provide a theoretical basis for improving the resistance of turfgrass and reducing water consumption. To
  1 Materials and methods
  1.1 Test materials
   The test seed was perennial ryegrass (Lolium perenne L.), the variety was Eisente No. 2, provided by Beijing Bright Grass Industry Co., Ltd. The water retaining agent is Water (organic-inorganic composite of acrylamide and attapulgite), provided by Shengli Oilfield Changan Holding Group Co., Ltd. The soil was taken from the Dushu Lake campus of Soochow University, and its basic fertility was organic matter 14.42 g/kg, available phosphorus 136.5 mg/kg, available potassium 374.8 mg/kg, pH 7.59. All reagents used in the experiment are of analytical grade. To
  1.2 Experimental design and method
Choose healthy and plump seeds, wash them with distilled water, blot them dry with filter paper, wrap them in clean gauze, soak them in 70% ethanol for 30 seconds, sterilize them with 1% potassium permanganate, and rinse them with distilled water repeatedly. Soak in sterile water for 24 hours. Place 3 pieces of sterile filter paper in the sterilized petri dish, spread the treated seeds evenly on the filter paper, and germinate for 48 h. First mix the soil and the water-retaining agent into a nutrient bowl. In the control, the water-retaining agent is not added. The full germinating seeds are sowed on the soil surface, covered with 0.5 cm of air-dried soil, and cultivated in a light incubator at a culture temperature of 20 ℃. The photoperiod is 12 h/d. After sowing, weigh and replenish water every day, and perform drought stress treatment after the lawn grass becomes a turf (about 60 days). At the beginning, the soil water content is set to the maximum field water holding capacity, and then the water supply is stopped so that the soil water content will naturally drop to 60%, 50%, 40%, 30% of the maximum field water holding capacity, and weighing and replenishing water every day. All indicators were measured every 5 days, a total of 4 measurements, and each treatment was repeated 3 times. The soil water content of the control was maintained at the maximum field water holding capacity (21%).  1.3 Sample measurement
Cell membrane permeability was measured by conductivity method; proline (Pro) content was measured by sulfosalicylic acid method; root vitality was measured by TTC method, superoxide dismutase (SOD) was measured by NBT method, catalase ( CAT) is measured by ultraviolet absorption method, and peroxidase (POD) is measured by guaiacol method. To
  1.4 Data analysis
  Data processing and drawing use Microsoft Excel 2003, SPSS 17.0 software. To
  2 Results and analysis
  2.1 The effect of water retention agent on the cell membrane permeability of lawn grass leaves
   The degree of damage to the leaf cell membrane can be reflected by the electrical conductivity value, which is related to drought resistance. It can be seen from Figure 1 that the relative conductivity of turfgrass under drought stress gradually increases with the extension of the stress time, regardless of whether water retaining agent is added or not. Under the stress of 30% of the maximum field water holding capacity, the relative conductivity of the water retaining agent treatments on the 3rd, 6th, 9th and 12th day decreased by 8.75, 8.01, 5.34 and 4.94 percentage points compared with the control, and the difference was not significant except for the 12th day. In addition, other treatments have significant differences. Under the stress of 40% of the maximum field water holding capacity, the relative conductivity of the water retaining agent treatment decreased by 2.22, 6.94, 3.66 and 6.79 percentage points compared with the control, and the difference was significant on the 3rd and 12th day. Under the stress of 50% of the maximum field water holding capacity, the treatment with water-retaining agent decreased by 3.80, 2.32, 3.25 and 1.22 percentage points compared with the control, and there was a significant difference between the 3rd and 9th day treatments. Under the stress of 60% of the maximum field water holding capacity, the treatment with water-retaining agent decreased by 3.17, 2.20, 1.53 and 3.08 percentage points compared with the control, and there was a significant difference between the 3rd and 6th day treatments. To
  2.2 The effect of water retention agent on the proline content of turfgrass
   It can be seen from Figure 2 that the Pro content of turfgrass gradually increased with the extension of the stress time. Under the stress of 30% of the maximum field water holding capacity, the Pro content of the water retaining agent treatment on the 3rd, 6th, 9th and 12th day increased by 6.10%, 13.06%, 21.91% and 15.83%, respectively, compared with the control. The difference between the 9th and 12th day treatments Significantly. Under the stress of 40% of the maximum field water holding capacity, the Pro content of the water-retaining agent treatment increased by 14.70%, 19.14%, 37.62% and 34.17%, respectively, compared with the control. Among them, the difference was not significant except for the treatment on the 6th day. Significantly. Under the stress of 50% of the maximum field water holding capacity, the Pro content of the water-retaining agent treatment increased by 4.58%, 25.73%, 14.34% and 32.72%, respectively, compared with the control. The difference in the other treatments was significant except for the insignificant difference on the third day. Under the stress of 60% of the maximum field water holding capacity, the Pro content of the water-retaining agent treatment increased by 67.88%, 65.70%, 56.49% and 46.56% compared with the control, and the difference in each treatment was significant. To
  2.3 The effect of water retaining agent on the vitality of turfgrass root system
   It can be seen from Fig. 3 that the root vigor of turfgrass under drought stress decreased with the addition of water retaining agent and the control without addition. With the extension of the stress time, under the stress of 30% of the maximum field water holding capacity, on the 3rd, 6th, 9th and 12th day, the root activity of the turfgrass treated with water retaining agent increased by 12.47%, 15.48%, 23.05% and 58.86 respectively compared with the control. %, there is a significant difference between the 9th and 12th day treatment. Under the stress of 40% of the maximum field water holding capacity, the root activity of the turfgrass treated with water retaining agent increased by 37.54%, 32.82%, 48.37% and 45.16%, respectively, compared with the control, and the differences in each treatment were significant. Under the stress of 50% of the maximum field water holding capacity, the water retention agent treatment increased by 22.94%, 21.69%, 15.74% and 39.67%, respectively, compared with the control, and the differences in each treatment were significant. Under the stress of 60% of the maximum field water holding capacity, the treatment with water retaining agent increased by 18.44%, 7.67%, 10.31% and 37.61%, respectively, compared with the control, and the difference was significant on the 12th day. To
  2.4 The effect of water retaining agent on SOD activity of turfgrass
   It is known from Figure 4 that the SOD activity of turfgrass under drought stress gradually decreases with the extension of the stress time. With the extension of the stress time, under the stress of 30% of the maximum field water holding capacity, the SOD activity of the water retaining agent treatment increased by 14.96%, 22.11%, 12.47% and 20.80% respectively on the 3rd, 6th, 9th, and 12th day. There was a significant difference between the 6th and 9th day treatments. Under the stress of 40% of the maximum field water holding capacity, the water retention agent treatment increased by 11.58%, 7.67%, 11.67% and 11.81% respectively compared with the control. Except for the insignificant difference on the third day, the other treatments had significant differences. Under the stress of 50% of the maximum field water holding capacity, the water-retaining agent treatment increased by 11.27%, 12.19%, 14.00% and 20.17%, respectively, compared with the control, and the differences in each treatment were significant. Under the stress of 60% of the maximum field water holding capacity, the treatment with water retaining agent increased by 11.07%, 13.02%, 7.46% and 3.96% respectively compared with the control. Except for the treatment difference on the 12th day, the difference in the other treatments was significant. To
  2.5 The effect of water retention agent on CAT activity of lawn grass
   Under drought stress, the CAT activity of turfgrass gradually decreased with the extension of stress time (Figure 5). Under the stress of 30% of the maximum field water holding capacity, on the 3rd, 6th, 9th and 12th day, the CAT activity of the water retaining agent increased by 33.73%, 16.36%, 5.99% and 8.32%, respectively, compared with the control, and the difference in each treatment was significant. Under the stress of 40% of the maximum field water holding capacity, the water-retaining agent treatment increased by 22.26%, 7.52%, 7.71% and 14.24%, respectively, compared with the control, and the differences in each treatment were significant. Under the stress of 50% of the maximum field water holding capacity, the water retention agent treatment increased by 12.64%, 9.32%, 13.24% and 10.18% respectively compared with the control. Except for the 12th day, the treatment difference was not significant, the other treatments had significant differences. Under the stress of 60% of the maximum field water holding capacity, the water-retaining agent treatment increased by 33.48%, 21.96%, 9.85% and 8.84%, respectively, compared with the control, and the difference in each treatment was significant. To
  2.6 The effect of water retention agent on turfgrass POD activity
   It can be seen from Figure 6 that with the extension of the drought stress time, the POD activity of turfgrass first increased and then decreased. With the extension of the stress time, under the stress of 30% of the maximum field water holding capacity, on the 3rd, 6th, 9th and 12th day, the POD activity of the water retaining agent treatment increased by 17.66%, 21.21%, 11.04% and 19.30%, respectively. Except for the non-significant treatment difference on the 9th day, the other treatment differences were significant. Under the stress of 40% of the maximum field water holding capacity, the water-retaining agent treatment increased by 11.23%, 12.52%, 15.44% and 21.59%, respectively, compared with the control. The treatment difference was significant on the 6th and 12th day. Under the stress of 50% of the maximum field water holding capacity, the water-retaining agent treatment increased by 8.82%, 11.73%, 7.92% and 11.01% respectively compared with the control, and the treatment difference was significant on the 6th day. Under the stress of 60% of the maximum field water holding capacity, the treatment with water retaining agent increased by 8.33%, 18.85%, 16.89% and 17.22%, respectively, compared with the control, and the treatment difference was significant on the 6th and 12th day.  2.7 The effect of water retention agent on the MDA content of lawn grass
   It can be seen from Figure 7 that regardless of whether water retention agent is added, the MDA content of turfgrass gradually increases with the extension of the drought stress time. Under the stress of 30% of the maximum field water holding capacity, on the 3rd, 6th, 9th, and 12th day, the water retention agent treatment decreased by 6.53%, 3.62%, 6.52% and 6.01%, respectively, compared with the control. Under the stress of 40% of the maximum field water holding capacity, the water retention agent treatment decreased by 5.91%, 12.19%, 14.99%, and 13.06%, respectively, compared with the control. Except for the treatment difference on the 3rd day, the difference was not significant, and the other treatments had significant differences. Under the stress of 50% of the maximum field water holding capacity, the treatment with water-retaining agent decreased by 6.19%, 3.49%, 8.81% and 10.01%, respectively, compared with the control, and the treatment difference was significant on the 9th and 12th day. Under the stress of 60% of the maximum field water holding capacity, the treatment with water retaining agent decreased by 5.93%, 10.87%, 14.86% and 24.80%, respectively, compared with the control. The difference was not significant except for the treatment on the third day. To
  3 Discussion 
  Plasma membrane is the interface and barrier between living cells and the environment. The impact of various adverse environmental factors on cells first acts on the plasma membrane, which manifests as increased permeability. The plasma membrane damage caused by stress is related to the outflow of electrolyte solutes, and the electrolyte extravasated from cells during water stress can be used as a measure of dehydration resistance. In this experiment, it was found that with the increase of stress intensity and time, leaf cell membrane permeability increased. Under the same stress level and time, the increase of leaf cell membrane permeability with water retention agent treatment was smaller than that without water retention agent. To
  Under drought stress, plant cells will actively form osmotic adjustment substances, increase solute concentration, and reduce water potential, in order to obtain water from the outside world and adapt to the bad environment. In this experiment, the Pro content of turfgrass increased rapidly under drought stress, and the Pro content gradually increased with the increase of stress intensity and time. Under the same degree of stress and time, the increase in Pro content of turfgrass treated with water retaining agent was greater than that without water retaining agent. To
   Under drought stress, the maintenance of root vitality in terms of nutrients and water absorption is very important for the drought tolerance of turfgrass. Its strength also has a significant impact on drought resistance and is an important physiological indicator of plant drought resistance. In this experiment, with the increase of stress intensity and time, the root activity of turfgrass decreased. After adding water-retaining agent, root vitality increased significantly. To
  Under drought stress, a large amount of active oxygen free radicals will be produced in plants, causing oxidative damage, which will cause serious harm to plants. These reactive oxygen free radicals are a type of free radicals produced by the plant's own metabolism. They can damage protein, plasma membrane, chlorophyll and other cell components. When these reactive oxygen species cause damage to cells, there are also reactive oxygen scavengers, such as SOD, CAT, and POD, to scavenge reactive oxygen free radicals and reduce the damage to cells. In this experiment, with the increase of stress intensity and time, the activity of SOD and CAT of turfgrass gradually decreased, and POD showed a trend of first increasing and then decreasing. But after adding the water-retaining agent, the enzyme activity was significantly increased compared with the treatment without addition. To
   MDA is the product of membrane lipid peroxidation. Its content can represent the degree of damage to the plasma membrane. The increase in its content can reflect the drought tolerance of plants, and its increase is inversely proportional to drought tolerance. This experiment showed that the MDA content in turfgrass was significantly reduced after adding water retention agent. The lower the MDA content, the stronger the drought resistance, which is consistent with Liu Guohua's research. It shows that after adding water-retaining agent, the permeability of leaf cell membrane is improved, but because of different stress time, the effect of water-retaining agent on it is different, indicating that water-retaining agent can improve the drought resistance of turfgrass. To
  4 Conclusion 
With the increase of drought stress intensity and time, regardless of whether water retention agent is added, SOD and CAT activities of turfgrass leaves continue to decrease, POD activity first increases and then decreases, MDA, Pro content and relative conductivity continue to increase. The root vitality continued to decrease. However, under the same stress intensity and time, the SOD, CAT, POD activities, Pro content and root vigor of turfgrass were significantly increased after the addition of water retention agent compared with those without water retention agent. MDA content and leaf relative conductivity were both increased. Significantly reduced. It shows that the water retaining agent has a significant effect on the drought resistance of lawn plants.

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