Ultraviolet Radiation Effect on Seed Germination and Seedling Growth of Common Species from Northeastern Mexico

Rahim Foroughbakhch Pournavab,Lidia Salas Cruz,Elly Bacópulos Mejía,Adalberto Benavides Mendoza,Maginot Ngangyo Heya

doi:10.3390/agronomy9060269

Rahim Foroughbakhch Pournavab, Lidia Salas Cruz + Show 3 more

Open Access

https://doi.org/10.3390/agronomy9060269

Copy DOI

Abstract

Light is the only key factor essential for plant growth, and ultraviolet (UV) rays, the harmful part of solar radiation, have the ability to decrease the metabolic rate in photosynthesis, causing deterioration in their growth. Accurate handling of the ultraviolet light that reaches the crops allows the improvement of different aspects of production, such as the shape and color of the plants, the precocity of the crops, and an improvement in the control of pests and diseases. The present study was carried out with the purpose of studying the responses in terms of germination and growth of four plant species—Glycine max, Triticum aestivum, Helianthus annuus, and Pinus maximartinezii—exposed to different doses of UV-C and UV-B radiation, for evaluation through the standard germination and accelerated aging tests, registering the germination rate (GR) and vigor (V), the number of normal seedlings (NS), and the average lengths of radicle (ALR) and plumule (ALP). Seeds treated with UV-C radiation showed a significant difference (p <0.05) between treatments (doses) and species, both in the standard germination and accelerated aging tests for the ALR and ALP variables. Seeds of G. max showed low sensitivity in both tests, with the dose 43.20 kJ/m2/day. The seeds of H. annuus and P. maximartinezii showed high sensitivity in both tests under UV-C radiation, with the doses 8.64 kJ/m2/day and 0.864 kJ/m2/day, respectively. Both tests under UV-B radiation showed a significant difference (p < 0.01) between species and treatments in the variables NS and ALP, with the minimum dose (T2).

Highlights

Ultraviolet solar radiation has received greater attention during recent years, mainly due to concern for the depletion of stratospheric ozone [1] and the increase in UV-B radiation [2] that has detrimental effects on the growth and development of plants
It represents a greater portion of the total radiation, UV-A radiation is less harmful than the rest of wavelengths of UV radiation [5]
The good tolerance to the UV radiation tested allowed the determination of the adequate doses, which correspond to the maximum dose (T3) of UV-C radiation (43.20 kJ/m2 /day) for the germination and vigor of soybeans, wheat, and pine, and the minimum dose (T2) (2.88 kJ/m2 /day) for sunflowers

Summary

Introduction

Ultraviolet solar radiation has received greater attention during recent years, mainly due to concern for the depletion of stratospheric ozone [1] and the increase in UV-B radiation [2] that has detrimental effects on the growth and development of plants. Apart from photosynthetically active radiation (PAR, 400–700 nm), plants are exposed to UV-A light (320–390 nm), UV-B (280–320 nm), and UV-C radiation below 280 nm [4]. It represents a greater portion of the total radiation, UV-A radiation is less harmful than the rest of wavelengths of UV radiation [5]. UV-B radiation of the ecologically relevant intensities is considered a modulator of physiological and morphological responses in plants [6]. It intervenes in Agronomy 2019, 9, 269; doi:10.3390/agronomy9060269 www.mdpi.com/journal/agronomy

Methods

Results

Discussion

Conclusion