Pollen viability is a key factor in reproductive success because non-viable pollen often results in the failure of reproductive and vegetable crops. A previous study examined the effects of extremely low frequency electromagnetic fields on wheat pollen viability and found decreased viability. However, no study has investigated the effects of electromagnetic radiation (EMR) at different power densities on pollen viability in plants under field conditions using actual mobile phone base stations.
Four sites with lush natural vegetation near mobile phone base stations were selected. All of the sites were located near Guru Nanak Dev University in Punjab, India. Since the sites were close to one another, they had similar microclimatic conditions, including temperature and humidity. All plant samples were collected from gardens or parks that were maintained using similar horticultural practices. At each site, three power density measurements were taken at similar times of day. The average power density for each site is as follows: S-1: 10 mW/m², S-2: 28 mW/m², S-3: 55 mW/m², and S-4: 150 mW/m². In February 2023, flowers from 12 different plant species, including chrysanthemums, dahlias, poppies, and roses, were collected at each site to test pollen viability. Four different stains were used for the pollen viability tests. All experiments were conducted in triplicate. Regarding the stains: Aceto-orcein (AO) stains nuclear chromatin; Alexander's stain (AS) indicates cytoplasmic integrity; triphenyl tetrazolium chloride (TTC) stains cellular respiration; and Lugol's stain (LS) highlights the starch content of each pollen grain. About 20,000 pollen grains were observed and counted under a light microscope, providing a sufficient sample size to detect subtle changes in viability. S-1 was defined as the control for the statistical tests.
Pollen viability ranged from 91% down to 68%. A trend toward lower viability with increasing power density was observed for certain strains across all species and strains. The difference in pollen viability within the same species when comparing S-4 to S-1 (the control) was at least 1%, with a maximum deviation of 12%. In many cases, the difference between S-1 and S-4 was statistically significant at p < 0.05. In general, the difference in pollen viability between the heavily exposed S-4 samples and the S-1 controls ranged from 4% to 6%.
Aceto-orcein produced the highest pollen viability in all species, while TTC produced the lowest values consistently. The authors suggest that these results indicate EMR from base stations disrupts pollen grain metabolism because TTC detects cellular respiration and enzymatic activity, both of which are direct indicators of metabolic activity. This study presents a novel methodology for field research.
Editor’s note:
The observed effects are consistent and are therefore unlikely to be due to chance. However, the effects are quite weak. A 1% difference in pollen viability at 87% is likely irrelevant. The largest observed difference was a 12% reduction in viability (from 90% at S-1 to 78% at S-4). This could potentially have a slightly detrimental effect over many generations. One drawback of the study design is the questionable control site (S-1), which had an average power density of 10 mW/m². This would be considered a "high-exposure site" in similar field studies near base stations. A control site with less than 1 mW/m² would have been preferable. The authors noted that their highest observed viability (91%) was lower than figures typically reported for this species under optimal conditions (approaching 99% viability). Therefore, it is possible that site S-1, with the lowest EMR exposure, still had adverse effects on pollen viability. Stronger effects would have been observed with a "truly EMR-free" control site. (AT)