番茄茎直径MDS的通径分析与数值模拟

以春夏季温室番茄为实验材料,研究充分灌溉条件下的茎直径变化指标日最大收缩量(MDS)与气象因子(水面蒸发量Ew、日最高气温Tmax、日均气温Tm、日均空气饱和差DVPDm、正午空气饱和差DVPDmd、日总辐射Rs和日辐射峰值Rmax)的相关性。结果表明,Rmax、DVPDm和Ew与MDS的直接通径系数为正,Rmax的直接通径系数最高,其次为DVPDm,二者与MDS的相关性达显著水平,但Ew与MDS的相关性未达显著水平,表明Rmax和DVPDm为决策变量,对温室番茄茎直径变化起直接作用。而Tmax、Tm、DVPDmd、Rs与MDS的直接通径系数为负,但各自总作用又都为正,表明它们主要通过Rmax和DVPDm对番茄茎直径变化起间接作用。据此建立了MDS与Rmax和DVPDm的模拟方程,经检验此方程达显著水平,预测值能够准确地反映出MDS实测数值的变化。

Path Analysis and Numerical Simulation of MDS of Tomato Stem Diameter

Taking tomato planted in plots in spring summer greenhouse as experiment material,the correlations between maximum daily shrinkage(MDS) in tomato stem diameter and meteorological factors such as water surface evaporation Ew,daily maximum temperature Tmax,daily average temperature Tm,daily average vapor pressure deficit DVPDm,midday vapor pressure deficit DVPDmd,daily total radiation Rs and daily maximum radiation Rmax were studied by using path analysis method.The results indicated that the direct path coefficients between Rmax,DVPDm,Ew and MDS were all positive.The Rmax’s coefficient is the highest and the DVPDm’s coefficient is the second.The correlations between MDS and Rmax,DVPDm were significant,but the correlation between MDS and Ew was not significant.Therefore,the Rmax and DVPDm were decision variables which controlled tomato stem diameter variation directly in greenhouse.In addition,the direct path coefficients between Tmax,Tm,DVPDmd,Rs and MDS were all negative,but their sum coefficients between direct and indirect path coefficients were all positive.Tmax,Tm,DVPDmd,Rs had indirect influence on tomato stem diameter variation through Rmax and DVPDm.Based on this conclusion,the simulating equation between MDS and Rmax,DVPDm was established which was significant through test,and the calculated values of MDS could reflect its observed values exactly.