Abstract
Seeds are effective and efficient plant reproductive and dispersal structures consisting of an embryo, food supply and protected covering. As the start of the next generation, seeds occupy a critical position in plant life history and in the survival of the species (Black et al., 2000). Seed husbandry formed the basis for early agriculture and eventual civilization. People learned to plant, harvest, and preserve the seeds of certain grasses for winter and they abandoned nomadic life to build permanent settlements (Copeland and McDonald, 2001). Long viability has allowed seeds to be passed from generation to generation, with some, e.g. the Indian lotus (Nelumbo nucifera) remaining viable for as long as 1000 years (Janick, 1986). Seeds are remarkably varied and diverse. The orchid species boasts the smallest known seed, a dust-like particle hardly visible to the naked eye (Copeland and McDonald, 2001). Large perennial plants typically have the heaviest seed size, e.g. coconut.. Shape ranges from round or oval in many seed species, to triangular, elliptic, elongated, spiked, thorned, and hairy or winged, depending on the natural method of disposal. Together with differences in size and shape, seeds are highly diverse in a number of other aspects, many of which are relevant to horticultural production and seed technology which has developed to address such issues as seed dormancy, viability and storage life.
Genetic variation in herbivore resistance and tolerance: the role of plant life-history stage and type of damage
