Effects of Reclaimed Water Irrigation on Photosynthetic Physiology of 8 Greenspace Plant Species

The photosynthesis relevant indices of 8 ornamental plant species were measured with LI-6400 photosynthesis system after having been irrigated with fresh water, fresh + reclaimed water, and reclaimed water. The 8 species experimented included Poa pretensis, Lolium perenne, Gypsophila sp., Ligustrum vicaryi, Duranta repens, Photinia serrulata, Lorpetalum chindense var. rubrum and Acorus calamus. The results showed that there were some differences in the photosynthetic indices among different plant species after irrigation with different water sources. The results showed that the transpiration rate of Ligustrum vicaryi, Poa pretensis and Lolium perenne irrigated by reclaimed water was lower than that of irrigated by clean water, but the result was reversed to the rest 5 species. The intercellular CO2 concentration measured from Acorus calamus, Poa pretensis and Lolium perenne irrigated by reclaimed water was higher than that of irrigated by clean water, and the result was reversed to the rest 5 species. The stomatal conductance of Gypsophila sp. irrigated by reclaimed water was lower than that of irrigated by clean water, but the result was reversed to Acorus calamus, Photinia serrulata and Duranta repens. The net photosynthesis rate of Poa pretensis and Lolium perenne irrigated by reclaimed water was lower than that of irrigated by clean water, and the result was reversed to the rest 6 species. All the above results illustrated that the short term irrigation with reclaimed water might promote growth and development of some greenspace plant species, and there were differences in the promotion effect among different species.