Photosynthetic apparatus performance of tomato seedlings grown under various combinations of LED illumination.

Ahmed F Yousef,Hafiz M Rizwan,Faxing Chen,Mohamed A A Ahmed,Hao Yang,Yong Xu,Jacek Wróbel,Muhammad M Ali,Hazem M Kalaji,Shehu Abubakar Tadda,Mayank Gururani

doi:10.1371/journal.pone.0249373

Abstract

It is already known that the process of photosynthesis depends on the quality and intensity of light. However, the influence of the new light sources recently used in horticulture, known as Light Emitting Diodes (LEDs), on this process is not yet fully understood. Chlorophyll a fluorescence measurement has been widely used as a rapid, reliable, and noninvasive tool to study the efficiency of the photosystem II (PSII) and to evaluate plant responses to various environmental factors, including light intensity and quality. In this work, we tested the responses of the tomato photosynthetic apparatus to different light spectral qualities. Our results showed that the best performance of the photosynthetic apparatus was observed under a mixture of red and blue light (R7:B3) or a mixture of red, green and blue light (R3:G2:B5). This was demonstrated by the increase in the effective photochemical quantum yield of PSII (Y[II]), photochemical quenching (qP) and electron transport rate (ETR). On the other hand, the mixture of red and blue light with a high proportion of blue light led to an increase in non-photochemical quenching (NPQ). Our results can be used to improve the production of tomato plants under artificial light conditions. However, since we found that the responses of the photosynthetic apparatus of tomato plants to a particular light regime were cultivar-dependent and there was a weak correlation between the growth and photosynthetic parameters tested in this work, special attention should be paid in future research.

Highlights

Our results suggest that the responses of the photosynthetic apparatus to light regimes are cultivation-dependent [77]
The photosynthetic efficiency of the plants of the two tomato cultivars tested was significantly altered as a function of the light regime applied
This was observed under both types of chlorophyll fluorescence applied measurements

Summary

Introduction

To obtain healthy and productive tomato plants, a highquality planting material is a necessity. Light (intensity, quality and duration) is one of the fundamental factors that determine the process of photosynthesis and plant growth [1]. Light affects the content of primary and secondary metabolites in plants [2]. Under artificial growing conditions, lighting system can determine the cost and nutrient quality of plants [3, 4]. Many researches have proved that the Light Emitting Diodes (LEDs) are a suitable light source for lighting growth chambers and greenhouses [5,6,7]. The recommendations for the appropriate light for a particular plant are still under discussion and open researches

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Conclusion