Probing the morphological developmental path of plant embryos by image tracking

An image analysis and pattern recognition system was applied to track the morphological changes of individual plant somatic embryos during the course of their development into mature embryos. A Fourier descriptor was used to transform the morphological information into quantitative features (Fourier features), which are amenable to mathematical and statistical analysis. At a given time point, the status of each developing embryo is represented by a point in the multidimension feature space spanned by these Fourier features. Connecting each point representing the individual embryos over time gives a trajectory which depicts the embryos' developmental "path" or history. Large variations in embryo development were observed, which is consistent with the population heterogeneity seen in batch embryo cultures. The rate at which each embryo progresses in the feature space was measured by a developmental vector. For embryos in a given class or developmental stage, the magnitude of the developmental vector exhibited a wide distribution. The results revealed that embryos with a higher developmental rate during the early stage of development had a higher chance of reaching the mature stage in a relatively short time. This single embryo tracking method is potentially a valuable tool in developing a correlation between the embryo's morphological features during the early stage of development and its eventual developmental fate. Copyright 1998 John Wiley & Sons, Inc.