Table 4.

Mean values (±SE) of yearly root increment under different amounts of precipitation (dry, ambient, and wet treatments) recorded in five years (2006–2010): results of one-way ANOVA analysis (NS: not significant, *P < 0.05, **P < 0.01, ***P < 0.001). Different letters denote significantly different values for rhizomes, roots, and total separately (Tukey HSD test (P < 0.05) after ANOVA).

Year	Yearly root increment
	Dry	Ambient	Wet	P
Lowland grassland
2006	58.8 ± 15a	103.1 ± 28b	103.2 ± 25b	**
2007	63.8 ± 16a	77.5 ± 17a	136.0 ± 63b	*
2008	48.5 ± 9a	57.6 ± 20a	110.1 ± 26b	***
2009	110.0 ± 19a	145.7 ± 43ab	182.4 ± 59b	NS
2010	112.4 ± 30a	117.6 ± 39a	118.1 ± 40a	NS
Highland grassland
2006	182.9 ± 38a	194.4 ± 41a	218.6 ± 29a	NS
2007	168.6 ± 54a	180.1 ± 53a	181.8 ± 44a	NS
2008	140.2 ± 30a	131.9 ± 56a	159.4 ± 32a	NS
2009	144.2 ± 46a	197.8 ± 50ab	235.6 ± 50b	*
2010	126.0 ± 44a	109.8 ± 29a	135.8 ± 49a	NS
Mountain grassland
2006	225.8 ± 69a	270.9 ± 44a	271.0 ± 73a	NS
2007	131.0 ± 28a	138.9 ± 75a	190.0 ± 83a	NS
2008	123.1 ± 59a	121.4 ± 41a	194.4 ± 47b	*
2009	183.5 ± 100a	168.0 ± 45a	354.8 ± 155b	*
2010	122.6 ± 34a	111.0 ± 31a	180.5 ± 23b	**