Growth rates and Huber values
Decreasing DGW significantly influenced the seasonal patterns of
assimilation area per branch, especially during the EGS (Fig. 7). The
average assimilation area accumulation per branch at each trial day was
greater in the shallow DGW sites than the deeper DGW sites during the
EGS (Fig. 7a). The growth rate of the branch assimilation area was
greater in the shallow DGW sites than the deeper DGW sites in the same
trial phase during the EGS (Fig. 7a and b). The branch assimilation
areas and growth rates were not significantly different among sites on
the same trial day during the LGS (Fig. 7a and b); growth rate slowed
and even became negative during the LGS as a result of summer droughts
(Fig. 7a and b). The mixed models revealed that growth stage had a
significant influence on the relationship between DGW and growth rate &
Huber values (F =5.07, P <0.01; F =6.23,P <0.01, respectively). We saw growth rates in
assimilation branches decrease as DGW increased during EGS (Fig. 8a) but
not LGS (Fig. 8b). Huber values increased as DGW increased during the
EGS (Fig. 8c) but not during the LGS (Fig. 8d).