The tomato seed as a model system to study seed development and germination

Over the past decades a number of plant species have developed into models to study different aspects of seed biology. Cereal grains have long been used to unravel the pathways and regulation of endosperm mobilization by the aleurone layer (Fincher 1989; Jones & Jacobsen 1991). Seeds of pea ( Pisum sativum) have been used extensively for the study of seed development and assimilate partitioning (Wang & Hedley 1991). Arabidopsis thaliana seeds are in use for molecular and genetic studies, employing large collections of mutants (Feldmann et al. 1994). In several cereals, such as maize (Zea mays) and wheat ( Triticum aestivum), extensive studies have been undertaken to improve seed quality, both for stand improvement and nutritional value. However, the tomato seed has been used most extensively to study the physiology and biochemistry of seed development, germination and dormancy. The tomato is a member of the nightshade family (Solanaceae) and belongs to the genus Lycopersicon. The fruits of the tomato plant have been used for human consumption since the sixteenth century. Today it is one of the major horticultural cash crops in the world and many new varieties are created each year by intensive breeding efforts to meet the different requirements all over the world. Because of its high economic value, many studies have been devoted to the improvement of its seed quality.