Abstract: This research studied the root development of Poa pratensis under four different levels of simulated precipitation. The simulated precipitation treatments were: heavy rain (HR, 25-50 mm precipitation each 24 h), moderate rain (MR, 10-25 mm precipitation each 24 hours), light rain (LR, <10 mm rainfall each 24 h) and control (CK, 60% of the simulated light rain). Treatments were maintained over an experimental period of 24 days. The research aim was to explore the effect of the different simulated precipitation rates on the development of the P. pratensis root system. It was found that the CK treatment was affected by drought and the HR group by flooding, whereas roots of the MR treatment grew well throughout the experiment. In terms of root morphology, root length, root surface area, total root volume, average root diameter and the number of root functions all increased significantly, specific root length and root dry weight density were more stable. Data root system configurations of the various treatments showed that the growth status of P. pratensis in the MR treatment was better than other treatments. In terms of root anatomical structure, by the 50th day, in the CK treatment affected by drought stress, the root structure was damaged, the ratio of cortex to root diameter, diameter of vascular cylinder and xylem duct decreased. Slight drought effects on root anatomical structure were observed in the LR treatment, while the root anatomical structure of the MR and HR treatments was normal. The above results indicate that the moderate rain treatment provided the most suitable water regime for P. pratensis.

Key words: Poa pratensis, morphological characteristics, anatomical structure, simulated precipitation