Decoated pepper (Capsicum annuum L. cv Early Calwonder) seeds germinated earlier at 25°C, but not at 15°C, compared to coated seeds.The seed coat did not appear to impose a mechanical restriction on pepper seed germination. Scarification of the endosperm material directly in front of the radicle reduced the time to germination at both 15°C and 25°C.The amount of mechanical resistance imposed by the endosperm on radicle emergence before germination was measured using the Instron Universal Testing Machine. Endosperm strength decreased as imbibition time increased. The puncture force decreased faster when seeds were imbibed at 25°C than at 15°C. The reduction in puncture force corresponded with the ability of pepper seeds to germinate. Most radicle emergence occurred at 15°C and 25°C after the puncture force was reduced to between 0.3 and 0.4 newtons. Application of gibberellic acid4+7 (100 microliters per liter) resulted in earlier germination at 15°C and 25°C and decreased endosperm strength sooner than in untreated seeds. Similarly, high 02 concentrations had similar effects on germination earliness and endosperm strength decline as did gibberellic acid4+7, but only at 25°C. At 15°C, high 02 concentrations slowed germination and endosperm strength decline.found that, by increasing the growth rate of the embryo, this restriction could be overcome. Red light induced growth in the lettuce embryo, enabling it to grow through the endosperm. Pavlista and Haber (10) proposed that both the mechanical force of the growing embryo pushing against the endosperm, and the enzymic weakening of the endosperm were necessary for lettuce seed germination. They observed that when weakening of the endosperm was inhibited, the embryos grew and buckled in the endosperm encasing but did not germinate.Jones (6) determined that the cell walls of lettuce endosperm were increasingly degraded with longer incubation times, and following germination the walls were extensively broken down. Tao and Khan (12) determined that endosperm strength did not appear to be directly related to radicle protrusion in lettuce seed. Halmer et al. (4) reported that enzymic degradation of a mannosecontaining polysaccharide in lettuce endosperm cell walls was by red light or gibberellin. Enzymic activity increased markedly only after radicle emergence and thus did not correspond with the movement of the radicle through the endosperm.Pepper embryos are surrounded by endosperm materials which make up the bulk of food reserves for the embryo and young seedling (2). The experiments which follow test the mechanical resistance of the seed coat and endosperm during germination of Capsicum annuum at optimal and suboptimal temperatures.Seed coats and surrounding structures may influence the ability of a seed to germinate through interference with water uptake, gas exchange, diffusion of endogenous inhibitors, or by mechanical restriction of embryo growth (5, 8). In seeds that do not have hard seed coats or require scarification for water uptake, other seed parts ...

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Sakata Seed America investigated the possibility of marketing a film-coated broccoli seed product. Film coating is the process of applying a colored polymer film material onto the seed surface that completely covers the seed and any seed pesticide. Film-coated seed has the benefit of providing uniform and precise pesticide placement, is dust free, safe to handle, can be highly visible in the soil, and has increased flowability in seed planters. The drawbacks arc the cost of the film-coating machinery and the film product as well as the slower application rate. The basic application procedure of film products to broccoli seed and the effects of film products on seed viability and seed storage will be discussed.

Capsicum annuum (‘Early Calwonder’) seeds germinated (radicle protrusion) in 8 days at 15°C and 4 days at 25°. The seeds have an endosperm 7 to 9 cells in thickness which lies directly in front of the radicle. The external appearance of the endosperm did not change until one day before radicle emergence, when the endosperm in front of the radicle enlarged and protruded outward. This change was accompanied by breakdown and loss of endosperm cellular integrity and reduction in endosperm thickness directly in front of the radicle, but not in other regions of the endosperm. Gibberellic acid (GA4+7) decreased the time for appearance of the protruding endosperm and radicle protrusion through the seed coat by one day. Cell wall degrading activity was detectable during the early stages of germination and became extremely high after radicle emergence. Seeds treated with 100 ppm GA4+7 showed slightly increased enzyme activity during early germination and differences became more pronounced as germination progressed. Cellulase activity was not found in the extracts, but seed enzyme preparations degraded a galactomannan substrate. The enzyme exhibited only endohydrolytic activity, indicating an enzyme which may participate in the weakening of cell wall. It was postulated that an endomannanase is needed for endosperm breakdown in front of the radicle in order for rapid germination of pepper to occur. A reduction in germination temperature from 25° to 15° reduced the rate of radicle movement through the seed coat by one half.