Data from: The response of root traits to precipitation change of herbaceous species in temperate steppes

1. Plasticity of root traits plays an important role in determining plant
growth and survival under changing climate. Shift in precipitation is one
of the most pertinent global change factors driving changes in structure
and function of grasslands. However, few studies have focused on
intra-specific variation of root traits in response to precipitation
change under field conditions. 2. We conducted a 10-year simulated
increased precipitation experiment in a temperate grassland and a 700-km
regional scale transect along a precipitation gradients ranging from
144.23 to 412.29 mm in northern China. The morphological, chemical and
anatomical traits of the first two orders roots were measured on 15 common
herbaceous species in the manipulation experiment and two regionally
common species (Leymus chinensis, Artemisia frigida) along the
precipitation gradients. 3. We found that most of the root traits of the
herbaceous species exhibited no significant responses to water addition.
The two regionally common species adjusted their root traits at sites with
the annual precipitation lower than certain value, i.e., 250 mm and 160 mm
for L. chinensis and A. frigida, respectively. These results indicate that
root traits of the herbaceous species exhibit little plasticity in
response to precipitation change, and that the adjustment of root traits
occurs when the range of annual precipitation exceeds a certain
thresholds. 4. Root traits of L. chinensis and A. frigida varied
differently both in manipulation experiment and along the precipitation
gradients. Root traits of L. chinensis were relatively constant, while A.
frigida adjusted their morphological root traits in response to water
addition. Moreover, L. chinensis showed higher specific root length and
area, and root N contents at sites with annual precipitation lower than c.
250 mm. In contrast, A. frigida displayed thicker roots with lower
specific root length and area at sites with annual precipitation lower
than c.160 mm. 5. Our results showed that root traits of herbaceous
species in temperate grasslands exhibited little plasticity, and that
different species have evolved diverse adaptive strategies in response to
precipitation change. These novel findings may provide valuable
information to predict responses of temperate grasslands to future climate
change.