Adaptability Evaluation Of Planting Bamboos In North From South And Physiological Response To Low Temperature

There is a lack of evergreen trees with strong ornamental value and high cultural value in the north of China,and planting bamboos in north from south can make up for this deficiency.Low temperature limits the large-scale planting of bamboos in the north.The adaptability and cold resistance level of different bamboo species in the same introduction site（in Tai’an）and the same bamboo species in different introduction sites（in Beijing and Liaocheng）were studied respectively,in order to systematically understand the adaptive effect of bamboo species and obtain more reliable and comprehensive theoretical support for planting bamboos in north from south.（1）Study the introduction effects of different bamboo species and different soil conditions,including the evaluation on the adaptability of bamboos to Tai’an,Beijing and Liaocheng.The external morphology of 20 bamboo species in Liaocheng was investigated and the cold resistance level was determined.In the subsidence area of Coal Mine in Qiuminghu Bamboo Garden in Tai’an,root activity of introduced Phyllostachys aureosulcata f.spectabilis and Phyllostachys propinqua were observed,and the growth indexes such as survival rate,diameter growth and high growth of mother bamboo and newborn bamboo were investigated for 2 years,which took Phyllostachys glauca which was Shandong native bamboo species as a control.It was found that Phyllostachys aureosulcata f.spectabilis performed better than Phyllostachys propinqua and Phyllostachys glauca,which proved that Phyllostachys aureosulcata f.spectabilis performed well as a northern green ornamental bamboo species and was suitable for extension.The adaptability of Phyllostachys propinqua is relatively weak,so protective measures should be taken in winter.Taking Phyllostachys aureosulcata f.spectabilis,Phyllostachys propinqua,Ph.vivax f.Huanwenzhu,Phyllostachys vivax and Phyllostachys nigra from Dayu Bamboo Garden in Yangzhou as controls,the shoot emergence rate of these five bamboo species in Zizhuyuan Park in Beijing and Baizhu Garden in Liaocheng was measured.The results showed that after long-term introduction,the shoot emergence rate of bamboo species in Beijing and Liaocheng was lower than that in Yangzhou,and the shoot ability of these two places was still insufficient compared with that in the south,and it could be improved by covering plastic film and straw.（2）Study the adaptability of bamboos in different soil conditions.In addition to water content,other chemical properties such as conductivity,p H,total nitrogen,hydrolyzable nitrogen,total phosphorus,available phosphorus,available potassium and organic matter content were all significant or extremely significant.The mother bamboo and newborn bamboo could grow normally under all soil conditions,but the growth performance of root system,height and diameter was better in shallow fly ash land,compost land and yellow clay land,which was suitable for extension.Potassium fertilizer and organic fertilizer can be properly supplemented in application.In addition,attention should be paid to the appropriate coverage depth of fly ash in coal mine areas,which should not be more than 30cm.（3）Study the physiological response of planting bamboos in north from south to low temperature during its northward migration.Six cold-resistant physiological indexes of five bamboo species from Yangzhou,Beijing and Liaocheng where the latitude is different by 3°were measured,including shooting rate,conductivity,SOD activity,soluble sugar,soluble protein,free proline,malondialdehyde.There were significant or extremely significant differences among different temperature,growth areas and bamboo species.And except that conductivity and malondialdehyde content were negatively correlated with cold resistance,other indexes were positively correlated.By fitting Logistic equation,the LT₅₀of bamboo species from different sources was obtained,and the LT₅₀of Phyllostachys aureosulcata f.spectabilis,Phyllostachys propinqua,Ph.vivax f.Huanwenzhu,Phyllostachys vivax and Phyllostachys nigra in Beijing were-27.4℃,-26.8℃,-24.1℃,-21.0℃and-18.3℃,respectively.And that of all bamboo species in Liaocheng were-26.0℃、-25.0℃、-23.2℃、-21.4℃、-16.4℃,respectively.And that of all bamboo species in Yangzhou were-24.4℃,-23.0℃,-21.1℃,-18.0℃and-15.2℃,respectively.The order of cold resistance of bamboo specieswasPhyllostachysaureosulcataf.spectabilis>Phyllostachys propinqua>Ph.vivax f.Huanwenzhu>Phyllostachys vivax>Phyllostachys nigra,and the order of that was Beijing>Liaocheng>Yangzhou.Ang the results of comprehensive evaluation of cold resistance by membership function method were basically the same.Therefore,after many years of introduction,the wintering cold resistance level of bamboo species in Beijing and Liaocheng had been significantly higher than that in Yangzhou,and with the increase of latitude and the decrease of temperature,the effect of cold acclimation of planting bamboos in north from south was significant.In landscaping,the suitable bamboo species of LT₅₀could be selected for cultivation according to local overwintering temperature.