Effect of TiO2 Nanoparticles on the Yield and Photophysiological Responses of Cherry Tomatoes during the Rainy Season

Hyo Gil Choi

doi:10.3390/horticulturae7120563

Abstract

The rainy season occurs mainly from June to July in Korea, and this season causes insufficient ambient light intensity for the growth of cherry tomato in a greenhouse. Titanium dioxide (TiO2), as a photocatalyst, is known to affect photosynthesis in plants. This study was carried out to investigate the influence of TiO2 foliar spray application on the yield and photophysiological responses of cherry tomato under low ambient light intensity during the rainy season in a greenhouse. Cherry tomato plants were treated with 100 mg·L−1 TiO2 (T1) or 200 mg·L−1 TiO2 (T2) nanoparticle suspension on 26 June. The control group was not treated with TiO2. In the O–J phase of the OJIP transient under a cloudy day (2 July), the slope in the control and T1 groups rose more sharply than that in the T2 group. Conversely, on a clear day (10 July), the J–I phase of the T2 group sharply increased compared to that of the control and T1 groups. On a cloudy day with low ambient light intensity, the rate of electron transport flux from QA to QB per photosystem II reaction center (ET0/RC) and carbon dioxide (CO2) fixation of TiO2-treated plants were increased compared to those of the control. However, on a clear day of high light intensity, the ET0/RC and CO2 fixation of the T2 group were lower than those of the control and Tl groups. The yield of fruit was increased in the T1 group over that in other treatments. TiO2 treatment reduced the size of the fruit and delayed the ripening time, but greatly increased the fruit hardness. These results suggest that setting the concentration and supply amount of TiO2 nanoparticles suitable for various environmental conditions should be prioritized in order to improve the effect of TiO2 nanoparticles in tomato cultivation.

Highlights

Due to the increase in CO2 emissions, abnormal weather phenomena have been increasing worldwide in recent years
These results suggest that setting the concentration and supply amount of TiO2 nanoparticles suitable for various environmental conditions should be prioritized in order to improve the effect of TiO2 nanoparticles in tomato cultivation
When TiO2 suspension was sprayed on the leaves, white water droplets were formed, after which the moisture evaporated, and only the white TiO2 nanoparticles remained on the leaves (Figure 2B)

Summary

Introduction

Due to the increase in CO2 emissions, abnormal weather phenomena have been increasing worldwide in recent years. This abnormal weather negatively affects agricultural productivity in Korea [1]. Abnormal weather phenomena have been added to this period, resulting in a significant decrease in light intensity and increased risk to crops [4,5]. During these low-light-intensity periods, useful technologies that can reduce the risk to horticultural crops are urgently needed [6]

Methods

Results

Conclusion