Study On Drought Adaptability And Cutting Growth Of Landscape Plants In 3 Vertical Greening Substrates

In order to explore the difference of cuttings growth and drought adaptability of different plant varieties in the traditional substrate and new solid soilless substrates,it was used to guide the actual greening construction process.In this study,5 landscape plants were used as test materials,including Hedera nepalensis、Trachelospermum asiaticum‘Ougonnishiki’、Ligustrum japonicum‘Howardii’、Gardenia jasminoides cv.prostrata、Euonymus japonica var.aurea-marginatus.3 vertical greeing substrates were used as test substrates,including traditional cuttings cultivation substrates,the Japan solid soilless substrate‘Pafcal’and the domestic solid soilless substrate‘Tan Mian’.The physical properties and water retention of the 4 substrates were determined,the cuttings growth and drought adaptability of 5 plant varieties in the 3 substrates were compared and analyzed.In the end,a comprehensive evaluation on the drought adaptability of 5 plants were carried out by factor analysis.The results showed that:（1）All 4 substrates are excellent substrates for the application of garden production.The substrate‘Pafcal’is closer to the traditional cultivation matrix,the substrate‘Tan Mian’is more closely to the traditional cutting matrix.There was a significant difference in the water retention of 3 cultivation substrates,which showed that:traditional cultivation matrix>Tan Mian>Pafcal.（2）In addition to the rooting situation of Ligustrum japonicum‘Howardii’in the‘Tan Mian’was worse,The rest of the plants took root preferably in 3 substrates.The vine plants are more suitable for growing in the‘Tan Mian’,and the woody plants grow better in the‘Pafcal’.（3）Phenotype performance indicators:The response time of drought stress of plants in the traditional substrate was significantly higher than that of solid soilless substrates;Recovery after water of plants in the traditional substrate is superior to the solid soilless substrates,‘Tan Mian’is superior to‘Pafcal’.Photosynthetic indicators:Most plant varieties have the largest variation of P_n,G_s,T_r and WUE in the‘Pafcal’,The second is‘Tan Mian’,The traditional substrate is the smallest.AQY and A_maxax have the largest decline in the‘Pafcal’.The chlorophyll content of plants in th etraditional substrate and‘Tan Mian’was increased,but decreased in the‘Pafcal’.After water rehydration,most plants have the best recovery in the traditional substrate,The second is‘Tan Mian’,and the‘Pafcal’is the worst.Physiological indicators:After water control,MDA and soluble protein content of 5 kinds of plants in 3 substrates are showed the trend of first increased after decreased.After the rehydration,the MDA content of Ligustrum japonicum‘Howardii’was still significantly higher than that before the control of water,and the rest basically recovered to or below that level before the control of water.Most plants have a larger variation of SOD and POD activity in the‘Pafcal’,and are more sensitive to the loss of water.（4）Results of comprehensive evaluation of drought stress:the plants had the strongest drought adaptability in the traditional cultivation substrate,and‘Tan Mian’had stronger,while‘Pafcal’had the worst,this was positively correlated with the water-retaining capacity of the 3 substrates.It is indicated that the water retention of matrix is the key factor for the safety of plants in summer drought environment.But Hedera nepalensis、Trachelospermum asiaticum‘Ougonnishiki’、Ligustrum japonicum‘Howardii’、Euonymus japonica var.aurea-marginatus had stronger drought adaptability in the solid soilless substrates.Because of the peat in the traditional substrate is non-renewable resources,and considering that the solid soilless substrate is not easy to lose soil particles,light,clean,environmental protection,easy to replace and so on,It can still be used as the good cultivation substrate of vertical greening.‘Pafcal’is more suitable for indoor and woody plants because of its good air permeability;Because‘Tan Mian’have good water retention,it is more suitable for urban roads and other vulnerable to drought stress area,especially in the northwest arid and semiarid areas in China,it is the first choice to promote use.