Study On Growth And Sewage Purification In Constructed Wetland Of 21 Ornamental Plants In Guangzhou

On the basis of investigating the ornamental plants in Guangzhou, we selected21 species as the material to study their growth condition, ornamental characteristicsand efficiency of purifying sewage in sub-surface constructed wetland.This wetland system collocated 21 ornamental plants, belonging to 7 families.Araceae (10 species): Alocasia macrorrhiza, Aglaonema commutatum'SanRemo', Dieffenbachia amoena'Exotica', Dieffenbachia amoena'TropicSnow', Spathiphyllum kochii, Anthurium andraeanum, Aglaonema modestum,Philodendron panduraeforme, Aglaonema commutatum'Silver Queen',Philodendron grazielae; Agavaceae (3 species): Dracaena deremensis 'Compacta',Dracaena sanderiana, Sansevieria trifasciata; Zingiberaceae (2 species):Hedychium coronarium, Alpinia zerumbet'Variegata'; Amaryllidaceae (2 species):Crinum asiaticum var. sinicum, Hippeastrum vittatum; Iridaceae (2 species):Neomarica gracilis,Iris tectorum; Commelinaceae (1 species): Rhoeo discolo;Bromeliaceae (1 species) : Neoregelia spactabilis. Of 21 plant species, all plantswere perennial herbage with 13 species being evergreen.Of all 21 plant species, the time of majority plants from sprouts growing intomature leaves centred in 8-13 days, and Dracaena deremensis 'Compacta'cost thelongest time for 8 months. After growing in the constructed wetland for one year,Hedychium coronarium achieved the highest increasing rate in height 12.23% withAnthurium andraeanum lowest rate -6.82%; Aglaonema modestum gained highestincreasing rate in tillering 97.86% with Dracaena deremensis 'Compacta',Dieffenbachia amoena 'Exotica', Crinum asiaticum var. sinicum, Dracaenasanderiana, Neoregelia spactabilis, Anthurium andraeanum lowest rate 0;Spathiphyllum kochii obtained the highest increasing rate in total leaves withDieffenbachia amoena 'Exotica' lowest rate -0.65%; Hedychium coronarium winedthe highest increasing rate in biomass 544.62% with Neomarica gracilis lowest rate4.46%. The differences among 21 species in these four indexes were significant (p＜0.05). The average removal rates for sewage TN,NO₃-N,NH₄-N,TP,SP,COD,BOD₅ of 21 species in this constructed wetland were 40%,35%,67%,64%,58%,44%,63% respectively. The ornamental plants with highest removal rates for sewageTN,NO₃-N,NH₄-N,TP,SP,COD,BOD₅ were Hedychium coronarium, Alocasiamacrorrhiza, Philodendron panduraeforme, Hedychium coronarium, Alocasiamacrorrhiza, Alocasia macrorrhiza, Dieffenbachia amoena 'Tropic Snow' separately.In these seven indexes, differences among 21 species in NO₃-N were quite significant(p＜0.01), in TN, TP were significant (p＜0.05),and in NH₄-N,SP,COD,BOD₅ were not significant (p＞0.05).Among 21 ornamental plants, judging by five indexes of growth condition,purification efficiency, biomass in aboving ground, root system and landscape, 10species were reckoned to be suitable plants adapted to constructed wetland habitat.They were Philodendron grazielae, Philodendron panduraeforme, Aglaonemacommutatum 'Silver Queen', Hedychium coronarium, Alocasia macrorrhiza,Dieffenbachia amoena 'Tropic Snow', Crinum asiaticum, Aglaonema modestum,Hippeastrum vittatum, Spathiphyllum kochii.