小麦根系性状无损估计的电容法参数优化及其在温室和大田的应用

Non-Destructive Estimation of Wheat Roots Traits: Optimization of the Parameters for the Electrical Capacitance Method and Its Application for Wheat Grown in the Greenhouse and Field

为了优化并建立电容(EC)原位估测小麦根系性状参数的标准化方法,分析了不同电极位置组合和不同激发频率下,盆栽小麦根系的EC值与根系性状的关系,以优化EC法测量的参数设置,并用两种水分条件下的盆栽及田间小麦进行验证。结果表明,优化后植物电极应位于靠近基部的主茎上,且避免与茎节及其他无关物体接触,土壤电极应靠近主茎基部;激发频率为1 kHz。以该设定参数测得的EC值与两种水分条件下盆栽小麦的总根长(TRL)、根表面积(RSA)和根干重(RDW)均呈正相关,水分充足条件下相关系数分别为0.667^(**)、0.554^(*)和0.485^(*),中度干旱条件下分别为0.504^(*)、0.425和0.453^(*)。田间测得的灌浆中期EC值也与TRL、RSA和RDW均呈正相关,相关系数分别为0.522^(*)、0.686^(**)和0.510^(*)。综上可见,优化后的EC法估测根系性状的测量参数,可用于小麦根系的无损估测和性状表型分析。

In order to optimize and establish a standardized method for in-situ estimation of wheat root traits by electric capacitance(EC),under different combinations of the electrode positions and the excitation frequencies,the relationship between EC readings and their root traits for wheat grown in pots was firstly analyzed to optimize a protocol for estimating wheat root traits in this study.This was further tested for wheat grown in pots under two water treatments,then in the field.The correlation analysis between the EC readings and root traits suggested that the optimized protocol was as follows:the plant electrode should be located in the main stalk close to the base without contacting with the nodes and other unrelated objects;the soil electrode should be close to the bottom of the main roots,with an excitation frequency of 1 kHz.Using this protocol,the EC readings were positively correlated with total root length(TRL),root surface area(RSA)and root dry weight(RDW)for wheat grown in pots under two water conditions,with correlation coefficients of 0.667^(**),0.554^(*)and 0.485^(*)for well-watered conditions,and of 0.504^(*),0.425 and 0.453^(*)for moderate drought.Furthermore,the field trials showed that the EC readings at mid grain-filling stage were also positively correlated with TRL,RSA and RDW,with correlation efficient of 0.522^(*),0.686^(**),and 0.510^(*).To sum up,the EC method can be used for phenotyping root traits to detect variety-specific differences.The protocol for using the EC method to estimate root traits was established,and the EC method can be applied for non-destructive investigation of root systems in wheat,which will greatly promote the phenotyping of root traits in wheat and other crops.