Unknown effects of daily‐scale solar activity on the plant growth: Data from 6‐year growth monitoring of Sphagnum riparium

Abstract

The influence of solar activity on plant growth has been studied for over 100 years, however, this phenomenon is still poorly understood on a daily scale. The data from extensive monitoring of the growth of peat moss Sphagnum riparium, which we are conducting in the mires of Karelia (Russia), may shed light on this issue. During the 6 years of observation, 161,190 shoots were measured, and 1075 growth rates were obtained. Considering together the growth rates with the sunspot number and involving data on seasonal temperature, we found previously unknown effects of daily‐scale solar activity on plant growth. It was found that the sunspot number weakly but significantly inhibits the growth of Sphagnum. The extreme sunspot number in the 4 days before the growth rate values have a stronger influence. The involvement of temperature data showed that inhibition in growth is observed only in the temperature range from 6.7°C to 15.3°C and disappears beyond these limits. In addition, the data obtained showed that the influence of sunspot number on the growth of Sphagnum is progressively increasing along the gradient from the minimum to the maximum of the 11‐year solar cycle. The study provides one of the first results on the effect of solar activity on plant growth on a daily scale. The results expand our knowledge of the biological effects of solar activity. Indirectly, they can also be useful to better our understanding of the ozone layer's involvement in this process.

Geomagnetic Anomaly in the Growth Response of Peat Moss Sphagnum riparium to Temperature

“…Since the geomagnetic K p index is affected by solar activity [ 28 ], which is also a weak growth factor for S. riparium [ 32 ], we do not exclude some contribution to the results. The cross-talk between UV-B photoreceptor UVR8 and phytochrome B signaling pathways provides the physiological basis for this view [ 60 ].…”

“…The study was carried out in the vicinity of the Petrozavodsk city, where in different years, two mires were research sites. The characteristics of these mires are presented in detail in previous papers [ 29 , 30 , 31 , 32 ].…”

“…They were carried out using the original geotropic curvature method [ 36 ]. The growth monitoring technique has been described in detail in previous papers [ 29 , 30 , 31 , 32 ].…”