FIGURE 3 Comprehensive allelopathic effect index ofElymus nutans extracts on highland crops.
3.2 Autotoxicity of Elymus nutans and its allelopathic
potential on perennial
grasses
The effects of the three types of
extracts on germination force of perennial grasses were shown in Figure
4a. The control’s germination
force of Siberian wildryegrass was greater than 65%, and that of other
four grasses were less than 50%, suggesting Siberian wildryegrass seed
has strong vitality and the emergence is uniform. The
pieces extract treatment resulted
significant decrease of
germination force of all tested
perennial grasses, with a biggest decrease by 58.8% of Chinese festuca
and smallest decrease by 14.6% of Kentucky bluegrass compared to
control. The pieces extracts treatment leads to significant decrease of
germination force of Siberian wildryegrass, Chinese fescue and Kentucky
bluegrass than those of whole extracts treatment. Root zone soil
extracts had no significant
allelopathic effect on germination force of Kentucky bluegrass and
crymophila bluegrass, but significantly lowered the germination force of
Siberian wildryegrass, Chinese
fescue, and drooping wildryegrass itself.
The germination percentage of the control of the five perennial grasses
were less than 70%. The germination percentage of perennial grasses was
decreased by the three kinds of extracts (Figure
4b). The whole
extracts decreased the germination
percentage of drooping wildryegrass, Chinese fescue, Kentucky bluegrass
and crymophila bluegrass except Siberian wildryegrass. The pieces
extracts and root zone soil extracts showed significant inhibitory on
germination percentage of Chinese
fescue and crymophila bluegrass compared to control and whole extracts.
The germination indexes of all
control were less than 40, indicating lower seed vigor of the tested
perennial grasses (Figure 4c). The reduction of germination index by the
whole extracts varied with donor plants. The biggest drop occurred in
drooping wildryegrass and crymophila bluegrass. The pieces extracts
reduced Siberian wildryegrass (38.1%), Chinese fescue (47.3%), and
crymophila bluegrass (40.2%), significantly. The root zone soil
extracts increased the germination index of Kentucky bluegrass by
24.3%, but decreased that of other four grasses.