How Shade and Sprays Affect Pomegranate Quality, Antioxidants, and Minerals

Jenn Hoskins
28th June, 2024

How Shade and Sprays Affect Pomegranate Quality, Antioxidants, and Minerals

Applying a shading net, particularly in combination with foliar sprays of silicon or potassium, significantly reduces the severity of aril whitening in Punica granatum fruits compared to untreated controls, a key finding that confirms an effective method for improving the fruit's quality in hot climates.

Image adapted from: Moradi et al. / CC BY (Source)

Key Findings

  • Researchers at the University of Tehran found that shading pomegranate trees significantly reduced aril whitening (AW) in hot and dry climates
  • Shaded pomegranate fruits had darker red arils, which are more desirable, and experienced less chilling injury during cold storage
  • The combination of shading and a 0.15% sodium silicate spray increased antioxidant enzyme activities and improved overall fruit quality
Pomegranate (Punica granatum L.) fruit quality is influenced by various factors, including visual, biochemical, and mineral characteristics. One common issue in hot and dry climates is aril whitening (AW), which negatively affects fruit quality. Researchers at the University of Tehran conducted a study to investigate the effects of shading and foliar minerals on the quality of pomegranate fruits during their development stages[1]. This study aimed to find practical solutions to enhance fruit quality and reduce AW. In this study, pomegranate trees were either shaded with a 50% green net or left unshaded. Additionally, foliar applications of potassium sulfate (K, 1% and 2%) or sodium silicate (Si, 0.05%, 0.1%, and 0.15%) were administered during two growing seasons. The results demonstrated that shading significantly reduced the severity of AW at harvest compared to the control group. Furthermore, fruits grown under shaded conditions showed lower L* and ⁰hue color values, indicating darker red arils, which are more desirable. Shading also significantly reduced chilling injury in cold storage compared to fruits grown in open fields. The combination of shading and a 0.15% Si spray increased the activities of superoxide dismutase (SOD) and catalase (CAT) enzymes while decreasing the activity of polyphenol oxidase and peroxidase enzymes. This enhancement in antioxidant enzyme activities is consistent with previous findings that silicon can improve plant stress tolerance by regulating reactive oxygen species (ROS) and enhancing antioxidant defense mechanisms[2][3]. Moreover, the study found that shading and Si 0.15% spray resulted in the highest total anthocyanin, antioxidant activity, and total phenolics content in the arils. These findings align with earlier research indicating that silicon can improve plant growth and development under stress by enhancing antioxidant properties and reducing oxidative damage[2][3]. Additionally, the combination of shading and Si 0.15% increased the macronutrient content of the arils, further contributing to improved fruit quality. The study concluded that covering pomegranate trees with shading and spraying them with Si in hot climates significantly reduced AW, increased antioxidant traits, and led to higher fruit quality. These findings suggest that practical interventions, such as shading and silicon application, can effectively improve the quality of pomegranate fruits grown in challenging climatic conditions. This research provides valuable insights for pomegranate growers seeking to enhance fruit quality and mitigate the negative effects of hot and dry climates.

FruitsAgricultureNutrition

References

Main Study

1) Fruit quality, antioxidant, and mineral attributes of pomegranate cv. Ghojagh, influenced by shading and spray applications of potassium sulfate and sodium silicate.

Published 27th June, 2024

https://doi.org/10.1038/s41598-024-65084-3

Related Studies

2) Silicon improves seed germination and alleviates oxidative stress of bud seedlings in tomato under water deficit stress.

https://doi.org/10.1016/j.plaphy.2014.02.009

3) Silicon Regulates Antioxidant Activities of Crop Plants under Abiotic-Induced Oxidative Stress: A Review.

https://doi.org/10.3389/fpls.2017.00510


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