How Melatonin Helps Young Apple Trees Resist Salt Stress

Jenn Hoskins
23rd April, 2024

How Melatonin Helps Young Apple Trees Resist Salt Stress

Image Source: Natural Science News, 2024

Key Findings

  • In China, melatonin helps apple seedlings resist soil salinity and alkalinity, improving growth
  • Melatonin-treated plants showed better root development and higher photosynthetic pigment content
  • The treatment also reduced harmful sodium levels in plants, maintaining a healthier ion balance
Salinity and alkalinity are significant challenges to agriculture, particularly as they affect the health and yield of vital crops. These environmental stresses can lead to poor plant growth, reduced quality, and lower crop yields. Scientists have long sought ways to enhance plant resilience to these conditions, and one promising avenue is through the use of plant growth regulators such as melatonin (MT). Melatonin, commonly known for its role in regulating sleep in humans, also has important functions in plant biology. Recent research conducted by Gansu Agricultural University has shed light on the potential of melatonin to mitigate the negative impacts of saline-alkaline stress on plants[1]. The study focused on M9-T337 seedlings, a type of annual plant, and subjected them to various treatments, including control conditions, saline-alkaline stress, melatonin treatment, and a combination of saline-alkaline stress with melatonin. Additionally, they explored the effects of adding an inhibitor to the melatonin treatment under stress conditions. Their findings revealed that saline-alkaline environments hinder plant growth by affecting photosynthesis, increasing harmful sodium levels, and boosting the production of reactive oxygen species—molecules that can damage cells. In a significant finding, the application of melatonin was shown to alleviate these detrimental effects. Melatonin-treated plants exhibited improvements in height, stem diameter, and root development, suggesting that melatonin could play a role in enhancing plant growth under stress. Moreover, melatonin helped plants maintain better water and nutrient balance, as evidenced by reduced sodium levels and lower Na+/K+ ratios, crucial for plant health. This recent study builds upon previous research that has identified various plant mechanisms for coping with salt stress. For instance, the role of calcium in helping plants manage saline-alkaline stress has been highlighted, with certain proteins like MsCBL4 improving plant tolerance by regulating calcium accumulation[2]. Additionally, the importance of maintaining a balance of hormones and antioxidants, such as superoxide dismutase (SOD), under salt stress has been emphasized in studies, as these components are vital for plant health and stress response[3][4]. What makes melatonin's role particularly intriguing is its multifaceted impact on plant physiology. Melatonin improved the plant's photosynthetic capacity, which is essential for growth and energy production. It also enhanced the plant's ability to regulate its internal water and nutrient content, further supporting its growth under challenging conditions. The study showed that melatonin could upregulate genes responsible for transporting harmful sodium out of the cells while downregulating those that bring in potassium, which is typically lost in high-salt environments. Furthermore, melatonin boosted the activity of antioxidant enzymes and increased levels of substances like ascorbic acid and glutathione, which are part of the plant's defense system against oxidative stress. This is particularly important as reactive oxygen species, which can damage cells, tend to accumulate under stress conditions. By enhancing the plant's antioxidant capacity, melatonin helps to protect it from these damaging molecules. The study also found that melatonin worked in concert with other plant hormones, such as auxin, gibberellin, and zeatin, to support plant growth under saline-alkaline stress. This suggests that melatonin's protective effects are part of a larger network of plant growth regulation, integrating various hormonal signals to adapt to challenging environmental conditions. In summary, the research from Gansu Agricultural University offers promising insights into the use of melatonin as a means to enhance plant tolerance to saline-alkaline stress. By improving growth, bolstering the antioxidant defense system, and maintaining ionic balance, melatonin could be a valuable tool in the development of more resilient crop varieties. This could have significant implications for agriculture, especially in areas where soil conditions are less than ideal due to high salinity or alkalinity. The integration of these findings with existing knowledge of plant stress responses can aid in the creation of new strategies for crop improvement and sustainable farming practices.

BiochemPlant ScienceAgriculture

References

Main Study

1) Exogenous melatonin strengthens saline-alkali stress tolerance in apple rootstock M9-T337 seedlings by initiating a variety of physiological and biochemical pathways

Published 22nd April, 2024

https://doi.org/10.1186/s40538-024-00577-x

Related Studies

2) Alfalfa MsCBL4 enhances calcium metabolism but not sodium transport in transgenic tobacco under salt and saline-alkali stress.

https://doi.org/10.1007/s00299-020-02543-x

3) Plant salt-tolerance mechanism: A review.

https://doi.org/10.1016/j.bbrc.2017.11.043

4) Effect of salt stress on the photosynthetic characteristics and endogenous hormones, and: A comprehensive evaluation of salt tolerance in Reaumuria soongorica seedlings.

https://doi.org/10.1080/15592324.2022.2031782


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