External Supports Affect The Climbing Growth And Plasticity Of Two Lianas

In recent years,due to the construction of urban development and urban expansion,urban green land area has become increasingly reduced,thus making full use of the vines for vertical greening has become an important way to expand urban green space,increase the amount of green.The climbing behavior of lianas is restricted by external support effectivenessdue to a lack of ability to erect growth,so climbing stem has great morphological plasticity and relative "mobile".Different forms of external support determine the strategy of lianas to seek light and external support.Thus the different external supportsplay an important role in the growth and adaptive behavior of lianas.At first,the paper selected the winding liana Clerodendrum speciosum as experiment material,the influence of different diameter support columns on their morphological and biological factors was studied by providing the diameter of 8 mm,16 mm and 24 mm bamboo respectively.Then the paper selected tendril liana Mansoa alliaceaas experiment material,providing different climbing columns,climbing netsto carry out the climbing experiment respectively.C limbing columnswere set as 8 mm,16 mm and 24 mm bamboo and 8 mm,16 mm and 24 mm PVC tubeaccording to the different diameter,climbing nets were set as 5×5cm hemp rope net,10×10cm hemp rope net,5×5cm nylon rope net,10×10cm nylon rope net according to the different mesh size and material,with no external support for control(CK).By measuring its shape index,biomass and their distribution,leaf character index and photosynthetic physiological indexes,the most adaptable climbing column and climbing net were selected to make the plant climb by itself.The impact of two factors(material and specification of external support)on liana growth was analyzed.The two lianas growth dynamics were analyzed under different external supports,and comparing the plasticity index of every indexes.The main results were as follo ws:(1)Clerodendrum speciosum had high ability of spiral wound on the 16 mm support column,and its branch number and branch of production rate were significantly less than other treatments(P< 0.05),plant leaf number and main stem length were significantly greater than 24 mm(P< 0.05).In terms of the biomass,plants had better biomass allocation on the above ground,and biomass allocation of the control group was significantly less than other treatments(P< 0.05).(2)The scramble of Mansoa alliacea was positively when climbing bamboo with 8mm or 16 mm in diameter,producing long stem,long internode and many tendrils.O n the support structure(stems and petioles),the biomass was accumulated more.Plants on 8 mm bambooincreasedleaf number,leaf area and leaf thickness to improve the ability of access to light,and the leaf number and leaf area are significantly smaller thanplants on 16 mm bamboo(P<0.05).Comparingtwo kinds of materials and three kinds of specifications of climbing columns,the results showed that the bamboo and 8 mm column were more advantageous to get the effective climbing.(3)Mansoa alliacea can achieve effective climbing growth on 5×5cm and 10×10cm hemp rope net,with the elongation of the main stem and internode,the increase of branches and tendril number and tendril length.Allocating more biomass on the stem,plant can support the most out of its own weight in order to achieve the goal of scattering branches and leaves.Comparing of climbing net with two kinds of materials and specifications,the results showed that the hemp rope net and 10×10 cm climbing net were more advantageous to make the plant climb positively.The correlation analysis of root system and aboveground showed that plant internode length and branch number increased with the increase of root surface area,thus plant can take good use of climbing net,generating branches and scattering leaves,forming vertical greening landscape.(4)The growth of Clerodendrum speciosum on the 8 mm support column,the number of leaves,and the growth of internode growth were significantly increased(P<0.05).Mansoa alliacea produced tendrils to improve its ability to climbing when they were climbing the 8mm and 16 mm bamboo.The increase of leaf number can make it get better light resources.The plants on the 5×5cm and 10×10cm hemp rope net can climb positively,with scattering the branches and increasing the tendrils number and height.(5)Clerodendrum speciosum on the support columns of different diameter had high biomass plasticity.Mansoa alliacea on the different climbing columns had high photosynthetic physiological and morphological plasticity.Plants on the different climbing nets had high biomass plasticity,morphological plasticity.And physiological and leaf photosynthetic plasticity were low,showing that the suitable climbing nets had a good effect on the morphological parameter,biomass accumulation and distribution.