Pre-Harvest Spermine Spray Can Dramatically Boost Litchi Yield, Shelf Life, and Nutritional Quality

Pre-Harvest Spermine Spray Found to Improve Litchi Yield, Colour, and Shelf Life: New Research on cv. Deshi

A new study published in Acta Physiologiae Plantarum provides strong evidence that pre-harvest application of spermine, a naturally occurring polyamine, can significantly enhance the ripening behaviour, yield, and postharvest quality of Litchi chinensis cv. Deshi. The research addresses a long-standing problem for litchi growers: rapid pericarp browning and short shelf life that reduce market value.

Why Spermine?

Litchi suffers from rapid color degradation within 72 hours after harvest due to oxidative reactions driven by enzymes such as polyphenol oxidase (PPO) and peroxidase (POD). Spermine—known for its antioxidant and membrane-stabilizing properties—was tested as a pre-harvest spray to reduce browning and enhance fruit quality.

Study Design

Researchers applied spermine at three concentrations (0.10, 0.20, 0.30 mM) at three growth stages:

20 days after fruit set
40 days after fruit set
Both 20 and 40 days

The experiment was conducted over two years using 36 litchi plants.

Key Findings

1. Delayed Ripening

0.10 mM spermine at 40 days delayed fruit maturity by 9 days compared to the control.
This delay provides growers more flexibility and extends the marketing window.

2. Higher Yield and Larger Fruits

The best yield and fruit size occurred with 0.10 mM spermine at 40 days, recording:

Fruit weight: 22.74 g
Yield: 24.24 kg per plant
Significant increases in fruit length, diameter, and volume were also recorded.

3. Reduced Browning and Enhanced Membrane Integrity

Spermine reduced key degradation markers:

Lowest membrane electrolyte leakage: 7.23%
Lowest PPO & POD activities, both strongly associated with browning.

4. Improved Antioxidant Profile and Nutritional Quality

Spermine-treated fruits had substantially higher:

TSS (up to 23.06 °B)
Total sugars
Anthocyanin content (up to 33.98 mg/100 g)
Ascorbic acid (up to 43.78 mg/100 g)
Phenols and flavonoids
Antioxidant capacity

These biochemical enhancements directly contribute to better flavour, colour, and storability.

Optimal Treatment Identified

Across all parameters, the most effective treatment was:

0.10 mM spermine was applied once at 40 days after fruit set
(with comparable benefits when applied twice at 20 & 40 days)

This concentration provided the best combination of:

Delayed ripening
Maximum yield
Best colour retention
Highest antioxidant activity
Minimum browning enzyme activity

Implications for Growers

The study demonstrates that a simple, low-dose, pre-harvest spermine spray can help farmers produce superior-quality litchi with enhanced market value, longer shelf life, and improved consumer appeal.

This eco-friendly alternative to postharvest chemicals supports both farmer income and consumer safety.

Reference

Kumari, J., Kundu, M., Mir, H. et al. Pre-harvest spermine application influences ripening, yield and quality attributes of Litchi (Litchi chinensis Sonn.) cv. Deshi. Acta Physiol Plant 47, 105 (2025). https://doi.org/10.1007/s11738-025-03854-w