[Objective] The dynamic changes of physiological indexes of ryegrass under different pollution conditions were studied

in order to provide a preliminary theoretical basis for phytoremediation of contaminated soil.[Methods] Through indoor simulation of different types of soil pollution

4 treatments were set up

namely uncontaminated soil + ryegrass (SH) as contorl

heavy metal contaminated soil (500 mg/kg Pb2+

50 mg/kg Cd2+)+ ryegrass (SGH)

petroleum contaminated soil (1 000 mg/kg petroleum) + ryegrass (SPH)

petroleum and heavy metals combined contaminated soil (500 mg/kg Pb2+

50 mg/kg Cd2+

1 000 mg/kg petroleum) + ryegrass (SPGH). The root morphological index was measured by WINRHIZO root analysis system

and the pigment index of leaves was measured by spectrophotometer

to explore the influence of different types of soil pollution on the pigment content of ryegrass leaves.[Results] The root growth of ryegrass was stimulated by three different types of contaminated soil to varying degrees. Compared with control

on the 20 th day

the root length

root surface area

root volume

and root diameter of plant roots under the combined treatment of petroleum and heavy metals increased by 88.10%

148.60%

221.90%

and 32.20%

respectively. Compared with control

the underground biomass of each polluted treatment showed a trend of increasing firstly and then decreasing with the increase of cultivation time

while the above-ground biomass was always lower than that of control. Moreover

on the 10th

40th and 80th days

the abovementioned biomass of the combined pollutted treatment was the smallest

which significantly decreased by 34.68%

45.42% and 58.05% compared with that of the control. On the 80 th day

the chlorophyll content of ryegrass in heavy metal contaminated soil

petroleum contaminated soil and petroleum and heavy metals combined contaminated soil was significantly lower than that of control

which decreased by 26.84%

44.82% and 47.02%

respectively.[Conclusion] Different pollutions could promote the morphological changes of ryegrass root system

and reduce the biomass and pigment contents of ryegrass

among which the combined pollution with petroleum and heavy metals have the greatest influence on the growth of ryegrass

followed by the treatment with petroleum pollution. Based on the difference of physiological response of ryegrass root morphology and growth to different polluted soils

some regulatory substances can be added to alleviate the toxic effect of pollution on plants in the future during the phytoremediation of contaminated soils

increase the biomass of plants and enhance the related physiological functions to improve the efficiency of pollution remediation.