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 t he course of their development into mature embryos. A Fourier descript or was used to transform the morphological information into quantitati ve features (Fourier features), which are amenable to mathematical and statistical analysis. At a given time point, the status of each devel oping embryo is represented by a point in the multidimension feature s pace spanned by these Fourier features. Connecting each point represen ting the individual embryos over time gives a trajectory which depicts the embryos' developmental ''path'' or history. Large variations in e mbryo development were observed, which is consistent with the populati on heterogeneity seen in batch embryo cultures. The rate at which each embryo progresses in the feature space was measured by a developmenta l vector. For embryos in a given class or developmental stage, the mag nitude 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 mat ure stage in a relatively short time. This single embryo tracking meth od is potentially a valuable tool in developing a correlation between the embryo's morphological features during the early stage of developm ent and its eventual developmental fate. (C) 1998 John Wiley & Sons, I nc.