Effects of sludge on growth and physiology of green plants

The sewage treatment process produced large amounts of sludge whose disposal has become a growing concern.The most effective utilization is applied on green plants.The up-to-data research about the effects of sludge on green plants growth and physiology were summarized in this review.Most of the research showed that sludge not only improved the quality,biomass and flowering of green plants,but also induced the accumulation of mineral elements,osmotic adjustment,hormones and enzymes metabolism,chlorophyll content and resistance enhancement.However,sludge constrain germination and seedling growth of green plants and the excess sludge poisoned green plants and caused heavy metal pollution of soil.