The Effect Of Substrate Depth For Light-Green Roof On The Turf Quality Of Six Sedum

This study evaluated the lawn establishment, turf feature and visual value of six Sedum species, which including Sedum lineare, S. sarmentosum, S. emarginatum, S. spurium cv.’Coccineum’, S. lineare cv.’Jin Ye’, S. aizoon, through the method of simulating the roof greening environment and using different depth of substratum, to explain it in detail, they were placed on the vegetation carrier at depths of2.5,5,7.5and10.0cm. Besides, the test studied the drought and heat resistant ability through the observation of their physical signs. The results were as followed:1)Deeper substrates promoted the growth of all species tested:The depths of5.0cm,7.5cm and10.0cm don’t have significant differences on formation speed, while the formation time of Sedum species at the2.5cm substratum depth was20days later than those of other three depths; it was concluded that turf quality were better along with deeper depth. Considering the turf quality of the whole year, species at the depths of7.5cm and10cm turned out to be best, then following the5cm depth, while those at the2.5cm depth were not so good. Therefore, the lowest demand depth of substratum on which all species can obtain basic growth need and perform visual enjoyment is5cm.2)There are distinguish characteristics in different species, such as bud germination, the ability of lateral growth and the vertical growth speed. Five speccies of Sedum have relatively strong bud germination. S. sarmentosum, S. spurium cv.’Coccineum’and S. emarginatum had higher bud germination than S. lineare and S. lineare cv.’Jin Ye’, while S. aizoon had the lowest one. The ability of lateral growth descended in the order of S. sarmentosum>S. lineare>S. lineare cv.’Jin Ye’>S. emarginatum>S. spurium cv.’Coccineum’; the vertical growth speed of S. lineare and S. spurium cv.’Coccineum’ are faster than S. lineare cv.’Jin Ye’ and S. emarginatum. A comprehensive evaluation on field performance of the six Sedum species was given on the base of subordinate function values analysis, and the results indicated that the order of turf quality in the whole year from high to low was S. spurium cv.’Coccineum’and S. emarginatum.>S. lineare and S. lineare cv.’Jin Ye’>S. sarmentosum. 3)Water and temperature were major factors which greatly limited the growth of Sedum species on roof greening. Five Sedum species were exposed to drought stress (without irrigation) and four Sedum species were exposed to high temperature stress. During the stress period, organizational moisture content, relative electric conductivity, malondialdehyde(MDA), superoxide dismutase(SOD) and proline(Pro) were determined. Through comprehensive analysis of five physical characters and natural performance of these Sedum species, it was concluded that the drought resistant ability of these five Sedum species decreased in the order of S. sarmentosum>S. lineare>S. lineare cv.’Jin Ye’>S. emarginatum>S. spurium cv.’Coccineum’; and the heat resistant ability of four Sedum species decreased in the order of S. emarginatum>S. lineare>S. sarmentosum>S. spurium cv.’Coccineum’.