Leaf Traits Difference And Effects Of Droughts On Cimbing Growth Of Woody And Herbaceous Vines

With the increasingly reduction of urban land resources for landscape,using climbing plants in vertical greening has become an important way to maximize urban green areas,enhance the effectiveness of green spaces and landscape features,and alleviate urban ecological and environmental issues.The existence and features of external supports have a great influence on the climbing growth of vines.On the other hand,leaf traits can intuitively reflect the ability that how plants adapt to the environment with various growth and resources strategies.References based on leaf traits will be helpful in the scientific application of two categories of climbing plants.In urban gardening applications,the traits of external supports faced by vines are more diversified,and it is a frequent situation for plants facing drought stress and more extreme and frequent changes in moisture and light conditions.Exploring different growth patterns and response behaviors of woody and herbaceous vines in climbing growing under drought stress is quiet meaningful,especially for the application of landscaping and management methods of the two types of vines.This will reflecting the ecological adaptability of climbing plants to the special environment of the city.This paper compared 10 leaf traits of 5 herbaceous vines and 9 woody vines,analyzed their position of them in leaf economic spectrum,explored the correlations between these leaf traits,and compared the adaptability of this two kinds of vines to different light intensities.In addition,Piper hancei and Syngonium podophyllum were selected to be observed in a climbing experiment,incuding drought stress and different climbing surfaces as variable factors.Through the determination of their morphological,biomass,leaf traits,photosynthetic and chlorophyll fluorescence indicators,suitable treatment for this two vines were obtained.Besides,the paper compared different responses of this two vines,the correlation between plant roots and above-ground growth traits and the drought resistance capacity.The main findings are as follows:(1)The comparison shows that the leaf width,leaf length,leaf shape index,leaf area,water content,relative water content,dry weight water content of herbaceous vines are significantly higher than woody vines(P<0.01).The specific leaf area and specific leaf volume were obviously higher than woody vines(P<0.05),and the leaf nitrogen content was also higher than that of woody vines.The leaf thickness,leaf dry matter content and leaf tissue density of woody vines were significantly higher than that of herbaceous vines(P<0.01).Herbaceous vines in the leaf economic spectrum tend to be in the end of the "rapid investment-benefit" species,and woody vines tend to be "slow investment-benefit" species.(2)The results of the changes in leaf traits of herbaceous and woody vines under different light intensities show that,in general,the adaptability of the herbaceous vines to the light environment is better than that of the woody vines.In herbaceous vines,Ipomoea cairica,Paederia foetida,Syngonium podophyllum and Epipremnum aureum are more adaptable to changes in light intensity,and Cissus verticillata is more suitable for the full light environment;in woody vines,Pyrostegia venusta and Trachelospermum jasminoides grow strongly in both light enviroments.Artabotrys hexapetalus is the most shade-resistant of these woody vines;Antigonon leptopus,Holmskioldia sanguinea and Mussaenda pubescens are secondly tolerant to shaded environment;Bougainvillea spectabilis,Allamanda cathartica,and Mucuna birdwoodiana are all more suitable for growth in full light conditions,with a poor shade tolerance ability.(3)The growth of Piper hancei and Syngonium podophyllum are inhibited under drought stress.Piper hancei and Syngonium podophyllum both climb well on woody surface.Piper hancei grow well on concrete surface too and Syngonium podophyllum grow well on concrete surface too.They both can produce more long aerial roots to create better climbing conditions,larger leaf area and more biomass accumulated on the leaves,aerial roots and root systems which shows a stronger ability to acquire resources.The specific leaf area of the leaves become larger;the net photosynthetic rate and the actual photochemical efficiency is higher,showing high light energy utilization efficiency,and all these means stronger photosynthesis ability.The results of fuzzy membership function analysis show that the drought resistance of two kinds of vines is relatively close,but Piper hancei is slightly stronger.The correlation between roots and above-ground parts indicated that the root length,main stem length,and leaf area of both 2 vines will increase with the development of root length and root surface area.Therefore,maintaining the humidity of the climbing surface and focusing on the roots of the plants enabled the plants to grow more quickly,to produce aerial roots for climbing,and promote the growth of main stem elongation and increase of leaf area,which can quickly cover the surface to form effective greening.(4)The growth and development of the underground and underground parts,the accumulation of biomass,and the photosynthetic capacity of the 2 vines with supports were significantly better than those of the unsupported treatments.On plank climbing surface,the number and length of aerial roots of both 2vines have significantly increased,presenting a better climbing condition than other climbing surfaces.According to this,using wooden structure on the climbing surface and keeping the humidity of the surface will promote aerial root development and speed up plant climbing coverage.Moreover,the root biomass of the two vines under the treatment of brick wall surface is relatively high,which is conducive to the development of the root system.