Study On The Selection And Adaptability Of Plant Materials For Roof Greening In ZhengZhou

Along with the development of social economy,soil resource is str-aining the land area could be used in greening is decreasing day by day.Th-erefore,roof greening has been one of the effective ways in adding the gree-ning area and increasing the green coverage rate.Taking Zhengzhou city as example,this paper investigated and summed up the current situation of roof greening,and built a roof garden on the roof of YuHua Business office build-ing in Beihuan according to the climatic conditions of Zhengzhou city to sel-ect plants suitable to the roof greening and study the stress resistance of thes-e plants.Results of the investigation on the current situation of roof greening in Zhengzhou shows:the plant materials used in roof greening is plentiful,but the repeated utilization ratio of some plants is quite high;the proportion of roof greening area to the available roof area is small;the maintenance and management of built roof garden in later stage is poor.To promote the sustai-nable development of roof greening and enrich the applications types of the plant materials,this study carried on the selection of the plant materials suita-ble to the roof greening of Zhengzhou;expect for the Sedums,this study foc-used on the development of some herbaceous and ground covers with strong adaptability,high ornamental value,low maintenance and lower energy cons-umption.To provide the theoretical basis and plant materials for the suitable plants selection of roof greening in Zhengzhou,the morphological and growing cha -racters and plant physiology of Sedum reflexum,Sedum spectabile,Dianthus chinensis,Iris tectorum,Chrysanthemum morifolium,Alliumporrum,Herba schizonepetae,Hemerocallis and Saponaria officinalis was preliminary studied,and the adaptability and the stress resistance indexes of these plants was obs-erved and tested in this study.Determination results of drought,cold and heat resistance indexes are as follows:Under drought stress,the order of plants drought resistance is:Sedum re-flexum,Sedum spectabile> Dianthus chinensis,Iris tectorum> Alliumporrum,Chrysanthemum morifolium,Herba schizonepetae > Hemerocallis,Saponaria officinalis.Determination on wintering rate and physiologic index indicates that the stronger the cold resistance,the higher the wintering rate.The order of the plants cold resistance is:Sedum reflexum,Sedum spectabile> Dianthus chinen-sis,Iris tectorum,Chrysanthemum morifolium> Alliumporrum,Herba schizonepetae > Saponaria officinalis,Hemerocallis.Determination on morphological and physiology indexes under heat stress basically shows the order of plants heat resistance as:Sedum reflexum,Sedum spectabile> Dianthus chinensis,Iris tectorum> Chrysanthemum morifolium,He-rba schizonepetae > Alliumporrum,Hemerocallis,Saponaria officinalis.Morphologic observation and stress resistance identification on the roof gr-eening plants shows that all the plants selected could basically suitable to the roof greening circumstances of Zhengzhou.Sedum reflexum,Sedum spectabi-le,Dianthus chinensis and Iris tectorum have strong resistance and high orna-mental value,and low requirements about the soil and irrigated conditions; Chrysanthemum morifolium,Herba schizonepetae and Alliumporrum have stron-g resistance and high ornamental value,but a certain requirements about the soil and irrigated conditions.The ornamental value of hemerocallis and Sapon-aria officinalis is high,but they need a certain soil and irrigated conditions,and the increasing of irrigating frequency and effective measures of cultivation and administration is essential.Experimental site followed observation shows:the high temperature in summer has the largest impact on plants,the growth of the Sedums is influenced,but it wouldn't die,and its landscape effects de-crease;Chrysanthemum morifolium,Alliumporrum,Hemerocallis,Saponaria officinalis all need regular watering in summer to maintains the growth.To sum up,the tested plant materials all presented high ornamental value and strong resistance.the Sedums,such as Sedum reflexum,Sedum spectab-ile have excellent performance in roof greening,and could be taken as the main materials of the roof greening in Zhengzhou city;Dianthus chinensis an-d Iris tectorum have strong resistance,high regrowth ability and ornamental value,so they could be applied mainly;Chrysanthemum morifolium,Alliump-orrum,Herba schizonepetae,Hemerocallis and Saponaria officinalis had high ornamenttal value,but they need strengthened watering and management to pr-esent a better greening effect.In the selecting experiment and the study on different plants adaptability,to confirm the real adaptability of different plants,it's essential to combine with the practical situation of the roof and carry out repeat field operation test.