According to 5-year means, both the greatest selleck chem inhibitor reduction (by 15 and 18%, resp.) and accumulation (10 and 17%, resp.) of the root biomass and TBB have been noted in the highland grassland (Figure 5). On the other hand, the mountain grassland was characterized by relatively stable variations in the amount of below-ground plant parts under different amounts of rainfall (Figure 5). In addition, the decrease in the amount of rainfall input resulted also in a lower amount of rhizomes in dry treatment than that in wet treatments in highland (significant in 2007�C2009) and lowland grasslands (significant in 2008) (Table 5).Figure 5Percentage increase or decrease in dry mass of rhizomes, roots, and total below-ground plant biomass (ambient treatment = 100%) in dry and wet treatments recorded in five years (2006�C2010).

Interannual changes in below-ground biomass of lowland Festuca grassland were characterized by fluctuation of data in a narrow range of values and differences between them were mostly not significant (Table 5). Nevertheless, several significant differences in roots and TBB between dry and wet treatments were found in the second year (2007). In highland and mountain grasslands, respectively, a considerable significant reduction of roots (by 327 and 565gm?2) and TBB (by 445 and 539gm?2) occurred in ambient treatments in the second year (2007) in comparison with the previous year. A decreasing tendency in the dry mass of these plant parts also occurred in the following two years, particularly in the dry treatment of the mountain grassland (Table 5).

The greatest significant differences between rainfall input treatments were here found in the third year when 1571 and only 1172gm?2 of TBB accumulated in wet and dry treatments, respectively. On the contrary, an increase in root and TBB mostly occurred in all treatments in the studied grasslands in the last year (2010). In all grasslands studied, the mean values of dry mass of rhizomes including shoot bases were also lower in the dry in comparison with wet treatments, but mostly not significantly (Table 5). In the highland grassland, however, the pronounced reduction of rhizomes recorded due to lower precipitation was mostly significant.4. Discussion4.1. Yearly Root Increments and Their Interannual VariationsOur assumption that root growth is affected by experimentally manipulated rainfall Brefeldin_A inputs was confirmed for all studied grasslands. However, this fact was documented by significant effects of rainfall input treatments in ANOVA analyses in lowland and mountain grasslands and by correlation analyses which demonstrated that the yearly root increment (YRI) increased linearly with increasing precipitation in lowland and highland grasslands.