Comparison of the effects of two laser photobiomodulation techniques on bio-physical properties of Zea mays L. seeds

Mohammed Hasan; Marlia M Hanafiah; Intsar H H Alhilfy; Ziad Aeyad Taha

doi:10.7717/peerj.10614

Comparison of the effects of two laser photobiomodulation techniques on bio-physical properties of Zea mays L. seeds

PeerJ. 2021 Jan 15:9:e10614. doi: 10.7717/peerj.10614. eCollection 2021.

Authors

Mohammed Hasan¹, Marlia M Hanafiah^{1

2}, Intsar H H Alhilfy³, Ziad Aeyad Taha⁴

Affiliations

¹ Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
² Centre for Tropical Climate Change System, Institute of Climate Change, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
³ Department of Field Crop Science, College of Agriculture, University of Baghdad, Baghdad, Iraq.
⁴ Institute of Laser for Postgraduate Studies, University of Baghdad, Baghdad, Iraq.

Abstract

Background: Laser applications in agriculture have recently gained much interest due to improved plant characteristics following laser treatment before the sowing of seeds. In this study, maize seeds were exposed to different levels of laser treatment prior to sowing to improve their field performance. The aim of this study is to evaluate the impact of pre-sowing laser photobiomodulation on the field emergence and growth of treated maize seeds.

Methods: The maize seeds were first photobiomodulated with two lasers: 1) a helium-neon (He-Ne) red laser (632.8 nm), and 2) a neodymium-doped yttrium aluminum garnet (Nd:YAG) green laser (532 nm). Following three replications of randomized complete block design (RCBD), four irradiation treatments were applied (45 s, 65 s, 85 s, and 105 s) at two power intensities (2 mW/cm² and 4 mW/cm²).

Results: Based on the results, maize seeds pretreated with a green laser and 2 mW/cm² power intensity for 105 s exhibited the highest rate of seed emergence (96%) compared to the untreated control seeds with a lower seed emergence rate (62.5%). Furthermore, maize seeds treated with a red laser for 45 s showed an increased vigor index compared to the other treatment options and the control (P < 0.01). The treatment groups also showed statistically significant differences in seedling growth characteristics compared to the control group p < 0.01. The green laser produced a significant enhancement of about 24.20 cm in seedling length, 8.2 leaves/plant, and 3.4 cm in stem diameter compared to the untreated seeds. Moreover, the green laser treatment showed 57.4 days to anthesis, which was earlier than the untreated seeds (61.4 days). The results showed that the protein, oil, and starch contents of the seeds irradiated with the green laser were 17.54%, 6.18%, and 73.32%, respectively, compared to the seeds irradiated by the red laser with 16.51%, 6.33%, and 71.05%, respectively.

Conclusions: The photo biomodulation of maize seeds using a green laser light can improve the field emergence, seedling growth, and seed quality of the treated seed compared to the red laser treatment.

Keywords: Field performance; He–Ne laser; Maize; Nd:YAG laser; Seed quality.

Grants and funding

Marlia M Hanafiah was supported by the UKM research grant (GUP-2020-034). This research was funded by the Ministry of Education Malaysia (FRGS/1/2018/WAB05/UKM/02/2). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.