The Regulatory Research Of Allomertric Exponent And Plant Interaction In Arabidopsis Thaliana Population

Interaction among individuals is central to community ecology.Plant's relative interaction index(RII)is a suitable for analysis of plant interactions,and it can be calculated by the mass of isolated individuals and the mass of plants with neighbors.The self-thinning rule relates plant mass to density when density dependent mortality(self-thinning)is occurring.In this study,individuals were not removed to control plant densities;instead, the experiment was designed to produce the desired densities by controlling the distance between individuals during transplant of the seedlings.The values of RII and allometric scaling exponent were determined from repeated measure of plant mass and harvest density at different neighbor distances in Arabidopsis.thaliana.Target plants with larger allometric scaling exponent grew with larger RII at same neighbor distance level,and there appears to be a synchronous positive relationship between the two values.A relationship model was constructed between RII and allometric scaling exponent through a parameter of neighbor distance,and the resulting model was evaluated in the laboratory using Arabidopsis.The spatial distribution of leaves is related to the exponent of the self-thinning relationship in plant populations.In this study,we evaluated the fractal dimension of rosette leaves of wild-type(WT)Arabidopsis thaliana and of an abscisic acid(ABA)-insensitive mutant(abi2-1)to test a model of the spatial distribution of leaf form in an Arabidopsis population based on subdivision of a cube surrounding the leaf into uniform boxes and to investigate ABA's affect on this model of the leaf.The values of the self-thinning exponent were -1.31 and -1.45 for WT and abi2-1.The mean dimensions of the box used to model the spatial distribution of leaf form,estimated using our model, were 2.08 and 2.03,respectively.By assuming that the box dimension equals the fractal dimension within the populations,the predicted self-thinning exponent equaled -1.40 for WT and -1.49 for abi2-1.When exogenous ABA was applied to both genotypes,the self-thinning exponent became -1.26 and -1.43 for WT and abi2-1,and the exponents predicted using the dimensions of the box were -1.37 and -1.46,respectively.The empirically predicted exponent equaled that predicted using the dimensions of the box (95%confidence interval).Empirical prediction of the spatial pattern using the two genotypes with and without ABA showed that ABA influenced the spatial form of the rosette leaves.Therefore,sensitivity to ABA can affect self-thinning through genetically determined changes in leaf form and its spatial distribution.