Drought Resistance Evaluation Of Nine Bamboo Species

Bamboo belongs to the subfamily Bambusoideae of Gramineae.It is an excellent forest resource with important ecological,economic and landscape benefits.It has played its unique advantages in ecological construction,environmental protection and urban greening.Bamboo plants in China are mainly distributed in the south of the Yangtze River which is warm and humid.But it is rarely used in the northern areas for the lackness of water.Only a small number of bamboo species have been successfully introduced,which can not meet the needs of evergreen plant species planting and ecological engineering construction in the north.In view of this phenomenon,nine kinds of bamboos were used in this experiment,namely,green groove bamboo,moso bamboo,cv.Aureocaulis,fernleaf hedge bamboo,rhapis excelsa,pleioblastus gramineus,pleioblastus amarus and pseudosasa amabilis.The drought resistance measurement(D value)was calculated by drought resistance coefficient method,fuzzy membership function method and principal component analysis method,and then the drought resistance levels of 9 bamboo species were comprehensively divided by cluster analysis method.At the same time,the correlation degree between each index and bamboo drought resistance was determined by grey correlation analysis method,The results are as follows:(1)With the extension of drought treatment time,the change of soil water content in the basin showed a decreasing trend.The longer the drought stress time was,the lower the soil water content was.Among them,fernleaf hedge bamboo had the highest decline rate and the worst water control and conservation rate;(2)In appearance,the damage level of Bambusa glaucescens was the highest,and the leaves were curly and yellow,followed by moso bamboo,fernleaf hedge bamboo and rhapis excelsa.and next are green groove bamboo,cv.Aureocaulis,pleioblastus gramineus,pleioblastus amarus,pseudosasa amabilis.(3)The physiological indexes of nine kinds of bamboos were detected during drought stress.Among them,the growth rate of the soluble sugar content was the fastest in bambusa glaucescens,and the slowest in cv.Aureocaulis.The accumulation of free proline content is the most in bambusa glaucescens,while the least in moso bamboo.The decrease rate of SOD activity wasthe fastest in bambusa glaucescens,while the slowest in green groove bamboo.For POD activity,it decreased the fastest in rhapis excelsa,while that of green groove bamboo decreased the slowest.For CAT activity,it decreased the fastest in pseudosasa amabilis,while the slowest in fernleaf hedge bamboo.The MDA content in bambusa glaucescens accumulated the most,while the least in rhapis excelsa.Chlorophyll content in bambusa glaucescens rose the fastest,while the slowest in cv.Aureocaulis.The leaf water content of bambusa glaucescens decreased the fastest,while that of rhapis excelsa decreased the slowest.(4)Through comprehensive analysis,the D values of green groove bamboo,moso bamboo,cv.Aureocaulis,fernleaf hedge bamboo,rhapis excelsa,pleioblastus gramineus,pleioblastus amarus and pseudosasa amabilis ware 0.532,0.437,0.700,0.460,0.338,0.537,0.610,0.709 and0.620,respectively.Therefore,the drought resistance of pleioblastus amarus is the strongest,and that of bambusa glaucescens is the weakest.The results of the gray correlation analysis showed that the correlation degree of catalase activity,peroxidase activity,superoxide dismutase activity,malondialdehyde content,soluble sugar content,proline content,chlorophyll content,leaf water content and damage grade with drought resistance were 0.905,0.880,0.903,0.821,0.870,0.647,0.879,0.910 and 0.765,respectively,which showed the correlation between leaf water content and drought resistance was the strongest,and that of free proline was the lowest.Finally,nine kinds of experimental materials were divided into 3 levels by clustering analysis of D value.The first grade was: bambusa glaucescens and cv.Aureocaulis;the second grade was: pseudosasa amabilis,pleioblastus gramineus,rhapis excelsa and green groove bamboo;the third grade was:fernleaf hedge bamboo,moso bamboo and bambusa glaucescens.