TL;DR:Light homogeneity is an important characteristic for plant growth. Uneven lighting means that some areas receive too much light while others receive too little, resulting in unequal plant growth. Furthermore, overlapping light can result in high intensity, causing leaf damage and significantly impacting plant health. To ensure consistent light distribution, lighting must be properly adjusted, and the QS Pro grow light is designed to give broad coverage and even lighting, making this procedure considerably easier.
Light homogeneity is crucial for plant growth, alongside other critical characteristics such as PPF and PPFD. Uneven illumination can be harmful to plants. Even modest unevenness can result in irregular plant development. Because of unequal light distribution, some leaves may receive too much light, while others may not receive enough to accomplish photosynthesis. This unevenness causes imbalanced growth, leading plants to tilt towards the light source, resulting in extended stems and sparse leaves, which eventually affects the plant's structural stability. Concentrated light can offer adequate intensity, but if not correctly controlled, it can expose certain sections of the plant to excessive light.
Light homogeneity is crucial for plant growth, alongside other critical characteristics such as PPF and PPFD. Uneven illumination can be harmful to plants. Even modest unevenness can result in irregular plant development. Because of unequal light distribution, some leaves may receive too much light, while others may not receive enough to accomplish photosynthesis. Plants with uneven leaves may experience these problems: one side of the leaves becomes increasingly sparse, followed by the plant tilting as it grows, and eventually, the stem bends. Currently, many grow lights on the market concentrate light, and when used over a large area, the above problems can easily occur—because the overlapping areas of different concentrated light sources can lead to overly intense light. Concentrated light sources can provide sufficient light intensity for plants, but they often require professional growers to adjust the light source. If you cannot position the grow lights correctly, it's very likely that some plants will receive improper lighting.
Why do plants avoid extremely bright light? To answer this topic, we must first describe the photosynthetic response curve.
Scientists first proposed the photosynthetic response curve in the late nineteenth century. As botanical study evolved, an increasing number of experiments used plants' ability to absorb carbon dioxide during photosynthesis to assess photosynthesis efficiency. Researchers confirmed that plants' photosynthesis varies depending on the amount of light they receive. This fluctuation is characterized by the photosynthetic response curve.
There are three stages to the photosynthetic response curve:
Initial Stage: As the light intensity increases, so does the plant's photosynthetic rate. This is the primary growth state for plants in natural settings.
Saturation:
When the light intensity reaches a specific level, the photosynthetic rate stabilizes, suggesting that it has achieved the light saturation point, which means that further light will not boost efficiency.
Excess:
Beyond the light saturation point, increased light intensity reduces photosynthetic rate. This is mostly because intense light triggers the plant's defensive mechanisms, resulting in irreparable leaf damage.
When light intensity surpasses the plant's light saturation point, the net photosynthesis rate (Pn) declines. Cotton plant Pn climbs in the 0-200 μmol·m⁻²·s⁻¹ range as photosynthetically active radiation increases, but then slightly falls after reaching saturation point. This suggests that photosynthesis efficiency can be reduced, influencing plant development and biomass accumulation. (Li, Y., & Wang, J. (Year). Effects of configuration mode on the light response. Journal/Conference Title.)
The rectangular hyperbolic correction model fits the light-response curve. (T: leaf temperature; Ca: reference chamber CO2 concentration; R2: coefficient of determination; Pmax: the maximum net photosynthetic rate; LSP: light saturation point; LCP: light compensation point; Rd: dark respiration rate; AQE: apparent quantum efficiency).
Another study on cann**** found that high light intensity above the saturation point caused a decrease in photosynthetic rate, a condition known as photosinhibition. It was discovered that increasing light intensity beyond this amount does not necessarily increase the concentration of essential chemicals such as THC, implying that too much light can harm plants' chemical composition. (Rodriguez-Morrison, N., et al. (2021). The effects of light intensity and UV exposure on the yield and secondary metabolite composition of canna***. Journal of Horticultural Science & Biotechnology, 96(1), 1-10.)
Excessive light can damage plant leaves. Magagnini et al. (2018) found that cannabis leaves suffered considerable damage from high-intensity UV light, including chlorophyll degradation and cellular structure breakdown. This not only affects photosynthetic efficiency but also has a negative impact on the plant's general health. The study found that plants activate preventive systems, such as antioxidant synthesis, to resist further oxidative damage, but these processes are insufficient to fully compensate for the damage produced by high light. (Magagnini, G., et al. (2018). The role of UV radiation in the production of secondary metabolites in canna*** plants. Plants, 7(4), 59.)
These flaws can have a significant impact on plant productivity, hence manual light uniformity adjustment is necessary. places with low PPFD should benefit from overlapping light, whilst places with high PPFD should avoid additional intensity. According to this theory, regulating the overall light dispersion to an even level is critical for plant growth. The QS Pro series is intended to reduce adjustment challenges by providing wide coverage and equal light dispersion, considerably increasing the grower's experience.