Abstract: In order to explore the effects of soil surface texture (sand and fine gravel) on seed germination and seedling growth in regions vulnerable to soil erosion, the effects of temperature and soil particle composition on seed germination and seedling growth of Paspalum wettsteinii were assessed. The study utilized topsoil collected from eroding areas to use as substrate, with 4 different temperatures (15, 20, 25 and 30 ℃) and 5 soil mixtures created by mixing different soil particle composition based on soil particle diameter. The results showed that the temperature and soil particle composition had a significant influence on seed germination and seedling growth of P. wettsteinii. The time to initiation of seed germination after seeding reduced, the duration of seed germination shortened, and the germination rate increased as temperature rose from 15 to 30 ℃. The seed germination rate, germination energy and seedling biomass at 20 and 25 ℃ were higher than other temperatures. The germination index, vigor index and seedling growth at 20, 25, 30 ℃ were significantly higher than that at 15 ℃. The root-shoot ratio of seedlings initially decreased and then increased, but was lowest at 25 ℃. The seed germination indexes were lowest in the soil with the composition of 100% coarse particles and highest in the soil with the composition of 25% or 50% coarse particles. With increasing coarse particles, the seedling shoot height increased, while the root length and root-shoot ratio of growth decreased. The above-ground and root biomass of seedlings were higher in the soil with the composition of 50% or 75% coarse particles. The results indicated that high proportion of coarse-grained soil was beneficial to shoot growth, while harmful to root growth, and the soil with the composition of 25%, 50% or 75% of coarse particles was propitious to seed germination and the accumulation of seedling biomass.

Key words: Paspalum wettsteinii, soil particle composition, temperature, seed germination, biomass