Response Of Ornamental Shrub Functional Traits To Various Light Environments

At present,there are some problems in urban forest,especially boreal urban forest,that the vertical structures and species diversity are simple and low.The lack of ornamental shrub species already has become the bottleneck in development of urban forest.In addition,plant functional traits are considered as the greater useful indexes to quantity plant ecological functions but there is few research to connect ornamental shrub functional traits and shade tolerance.Therefore,this study determined response of ornamental shrub functional traits to various light environments through a vestigation in urban greenland and a field experiment.What’s more,growth strategies of ornamental shrubs also were determined.Above all,for the urban greenland vestigation,11 shrub species,such as Lonicera maackii and Deutzia parviflora,without pruning were chosen as the targeted shrub in the gap and under the canopy in the campus of Beijing Forestry University.Then shrubs’ twig and leaf phenotypic functional traits were measured and the intensity of photosynthetically active radiation(PAR),red light and far red light around the shrub were measured as the light environment indexes;Secondly,the field experiment conducted in a nursery in Baifu Village in Beijing.I set up a split plot design to treat 4 species including Sambucus williamsii,Deutzia parviflora,Lonicera maackii and Callicarpa bodinieri in different shade degrees and light quality types by covering light filtering cloth and shading cloth.Then,shrubs’ twig and leaf phenotypic functional traits and chemical nutritive element contents of organs were measured and the intensity of photosynthetically active radiation(PAR)9 red light and far red light around the shrub were measured as the light environment indexes.Finally,ANOVA,correlation test,regression and standardized major axis test were used for data statistics.Therefore,the main conclusion below:Ornamental shrubs would adopt strategies to avoid being shade.They usually improve the capacities of capturing light and photosynthesis.These behaviours were found because of their plastic responses to different light environment and variation across light gradient.Then,plants adopt tradeoff or investment preference to adapt the environments.The reasons are:(])optimized allocating their own limited resource to adapt environment changes;(2)selecting organ growth pattern to maximize efficient of resource utilization;(3)making concession on trait growth pattern to follow organ growth laws;(4)filtrating similar functional type traits to reduce cost.In addition,ornamental shrubs have the similar response to shading treatment and light filtering treatment.Both of light quantity and quality would affect shrub’s growth pattern.