Effects of Hydrogen-Rich Water on the Growth and Photosynthetic Characteristics of Cucumber Seedlings

Aims: The aim of the paper was to study the effect and specific mechanism of hydrogen-rich water (HRW) improving cucumber (Cucumis sativus) seedlings growth.

Study Design: 14-day-old cucumber seedlings were treated with different saturation hydrogen-rich water in root for three times every three days. After one day of the last treatment, growth parameters were determined and plants tissues were sampled for test photosynthetic characteristics.

Place and Duration of Study: In 2017, cucumber (C. sativus ‘JinYan4’) were germinated in College of Bioscience and Biotechnology of Shenyang Agricultural University (Lab ChuangXin).

Methodology: 20 cucumbers and 3 replicates were determined for growth parameters. The determination of total soluble sugar and soluble protein content are the methods of Anthrone colorimetry and Coomassic Brilliant Blue. Chlorophyll content was tested by using ethanol immersion extraction method. Gas exchange parameters were measured with LI-6400XT portable photosynthesis system. Chlorophyll fluorescence parameters of leaves were measured by a Handy PEA Fluorometer.

Results: Our results showed that 50% saturation HRW significantly enhanced the growth and development of cucumber seedlings, including the improvement of fresh weight, plant height, stem diameter and leaf area. These responses were consistent with a significant increase of leaf water content, total soluble sugar content and soluble protein content, which was further confirmed by the determination of photosynthetic related parameters. Also, research results illustrated that HRW up-regulated chlorophyll content and changed chlorophyll fluorescence parameters of leaves. The increase of chlorophyll content promoted the absorption of light and enhanced plant photosynthesis. Furthermore, HRW changed the leaf stomata conductance and decreased transpiration so as to improve the photosynthetic rate.

Conclusion: Taken together, these results suggest that the effect of HRW on cucumber seedling was associated with plant photosynthesis. Therefore, the application of HRW may be a promising strategy to improve cucumber growth.