Quantifying Root Architecture And Evaluation:Case Study Over Songnen Meadow Steppes Plants

Plant root architecture plays important part in root morphology and functions in relation to ecology and physiology,as a current hotspot in international root ecology research.However,for a long time,how to quantify spatial architecture of plant roots integratively has been a critical challenge.So far,a simple and effective root architecture integrative quantification method is lacking,which constraints using root architecture parameters in ecological models and deeply understanding the root architecture functioning and mechanisms in in-depth research work.This paper,based on the basic classification of plant root morphology over the Songnen Meadow Steppes representative plants,theoretical analysis plus data mining from historical literature,field investigation and laboratory measurement,raised a method to quantify the root architecture integrative,i.e.the R_arc approach.Then,the database of plant root architectures of the Songnen Meadow Steppes was established.By use of the R_arc method,this paper examined the relationships between plant root architectures and soil stability over the steppes,which are to evaluate application of the R_arc method.The main results were as follows:?1?According to morphological patterns of plant roots,spatial architectures of the representative plant roots in the Songnen Meadow Steppes were classified into four types: taproot architecture,fibrous root architecture,rhizomatic root architecture and tuberous root architecture.By means of field survey in the steppes,51 plant species were selected to conduct the grouping,which consisted of 28 species of taproot plants,accounting for 55%,15 species of rhizomatic root plants,accounting for 30%,and 8 fibrous root plants,accounting for 16%.?2?This paper presented the R_arc method to quantify the integrative root architectures;established the Amoeba diagrams to quantify the integrative root architectures,and explored computing the root architecture value?Rare value?.By taking the representative plants in the Songnen Meadow Steppes as examples,Amoeba diagrams of 25 species of the plants were drawn,and the Rare values were figured out,respectively.The results showed that there existed significant differences between Rare values among the Songnen Grasslands plants.?3?The R_arc values calculated through the R_arc approach were positively correlated with soil stability.For example,the R_arc value of Leymus chinensis was bigger than that of Chloris virgata,and lab water dispersal test showed that Leymus chinensis could anchor the soils more robust than Chloris virgata.This implies the R_arc value can well indicate the ability of plant roots in anchoring soils.?4?Positive correlations between singular root diameter and maximum tensile force,and negative correlations between root diameter and maximum tensile strength,existed in the plants over the Songnen Meadow Steppes.With increase of root diameters,maximum tensile forces also increased in power functions,whereas maximum tensile strengths decreased in power functions.?5?In the Songnen Meadow Steppes,plants revealed diverse root tensile forces and root tensile strengths.The paper proposed a simplified and effective approach to quantify the integrative root architecture,which fulfiled parameterizing the integrative root architecture.The results may provide scientific supports for using root architecture parameters in ecological models and in-depth understanding root ecology mechanisms,database construction and data accumulation regarding plant root architectures.