The viability of beech seeds (Fagus sylvatica) originating from the Republic of Moldova under high positive temperatures

Abstract

Under the conditions of the ongoing climate change, the ripening seeds of the beech Fagus sylvatica L. in the Republic of Moldova during the autumn period are exposed to long-term effects of the high temperatures, which may adversely affect their germination. The purpose of our research was to study the effect of different doses of supraoptimal temperatures on the viability and germination of Fagus sylvatica seeds harvested in 2021 from Hîrjauca, the Republic of Moldova. The viability of beech seeds was determined by two rapid tests: a) evaluation of enzyme activity by 1.0% of 2,3,5-triphenyltetrazolium chloride (TTC); b) forced germination by 1% hydrogen peroxide (PH), which have the good correlation (Pearson coefficient 0.8281). Initial viability of beech seeds was 80.0 by TTC and 79.0% by PH test. The beech seeds were exposed to short times (30, 45, 60 min) heat at 50ºС and 60ºС. The significant decrease in viability by 39% was establish after seed treatment at a temperature of 60ºС for 30 min (LSD0.05=16.58, p0.05). The heat treatment at minimal tested dose (50ºС for 30 min) before the stratification led to a decrease in viability and germination rate of beech seeds. After two months of germination in coconut substrate, the emergence was only about 18.5%. The roots length of survived seeds after heat treatment did not differ significantly from intact seeds (LSD0.05= 0.34, p>0.05).