# Effect of Photosynthetic Photon Flux Density on Paprika Seedling Growth Using Rockwool Block

## TL;DR

This study examines how different light intensities affect the growth of paprika seedlings grown in rockwool blocks.

## Contribution

The study reveals specific quantitative relationships between photosynthetic photon flux density and seedling growth metrics.

## Key findings

- Higher PPFD of LED light improves seedling quality, with 200 μmol·m−2·s−1 treatments showing 35% higher leaf area and 70% higher dry weight than lower treatments.
- Natural sunlight resulted in better leaf number and area compared to 150 μmol·m−2·s−1 LED treatments.
- Linear regression models show strong correlations between PPFD and leaf area (R² = 0.9307) and dry weight (R² = 0.9674).

## Abstract

This study was conducted to investigate the effects of different levels of photosynthetic photon flux density on the growth of paprika seedlings cultivated in rockwool blocks. The seedling height and internode length were significantly shorter in LED light treatments than in sunlight, and there was no difference among the PPFDs of LED light. On the other hand, leaf number and area of seedlings were significantly higher and wider, respectively, in sunlight than in 150 μmol·m−2·s−1 treatments. The influence levels on the dry weight were 20% lighter than those on the fresh weight. The higher the PPFD of LED light, the better the seedling quality. The leaf area and dry weight of seedlings in 200 μmol·m−2·s−1 treatments were 582 cm2/plant and 2.01 g/plant, respectively, higher by 35% and 70%, respectively, than in 100 μmol·m−2·s−1 treatments. The leaf area (Y1) had a significant dependence on PPFD (x), as Y1 = 75.3x + 368 (R2 = 0.9307 **). Also, the dry weight (Y2) of the seedlings showed a linear regression equation, as Y2 = 0.415x + 0.811 (R2 = 0.9674 **). The chlorophyll content based on the SPAD value significantly increased as the light intensity increased to 50 μmol·m−2·s−1. When the results were synthesized, the seedling quality was lower in the natural light conditions than in the 150 μmol·m−2·s−1 treatments.