High hydrostatic pressures (30-200 MPa) have been utilized for accelerating the germination of winged bean (Psophocarpus tetragonolobus, "Urizun") seeds. This pressure treatment promoted rapid germination of seeds and increased the germination percentage; it was especially effective in the germination of hard seeds. To confirm the acceleration mechanism of germination, water absorption parts were investigated under the pressure treatment. Furthermore, the changes in the water absorption content, leakage of solutes from seeds and individual sugar contents were also analyzed. As a result it is assumed that the effect of pressure treatments is at least partially physical leading to the improvement of water penetration, especially through the micropyle and seed coat, with a resulting acceleration of hydrolysis of sugars and other physiological processes associated with germination

The vigour of four sugar beet genotypes (NS-Hy 92, NS-Hy 11, NS-M1 and KW Maja) was studied during two years by applied vigour tests. The seed was of known physical qualities and belonged to size fractions of 4.25 mm and 3.25 mm. Germination capacity was determined by using fold filter paper method and the following vigour tests were applied: accelerated aging test, controlled deterioration test and cold test. These results were compared with the results obtained for field germination. The significant correlation coefficient was found between laboratory and field germination, and between cold test and field germination in both years of investigation.

The results of the study revealed a significant difference between pregermination treatments with regards to percent germination and seedling physical performance. Seeds treated with mechanical scarification is effective than potassium nitrate 0.2 percent solution in increasing germination but the seedlings were not as vigorous as those seeds treated with potassium nitrate regardless of the depth of sowing. There were no significant differences among treatments in terms of plant height, and the occurrence of pest and diseases

A laboratory investigation was carried out to determine the operating mechanism of dormancy in cold-stored Juniperus procera seeds. Three seed presowing treatments were applied to break dormancy in various parts of the seeds which were subsequently tested for germination. Embryos of the seeds expressed full germination both with and without the treatment precluding the existence of any form of embryo dormancy. Whole seeds also exhibited a fair percentage of germination but embryos surrounded by megagametophyte tissues showed very poor germination, both with and without the treatment. The study concludes that the best pre-sowing treatment for J. procera is physical scarification by nicking of part of the seed coat. However, further trials could be carried out to develop a cheap and appropriate pre-sowing treatment for J. procera seed to facilitate large scale seedling production of this species.

Seed (embryo) viability was investigated in seven species of the tropical legume genus Inga to determine the relationship between desiccation tolerance and the physical and/or chemical characteristics of the embryo. For all species, final germination (radicle emergence) percentage of isolated embryos was maximal at a temperature between 16 deg C and 31 to 36 deg C. Lower levels of germination were seen at 11 deg C in a majority of species. Below this temperature the few seeds that germinated did not produce epicotyls. Linear relations were observed between the dry weight of the embryonic axis and the cotyledons. Desiccation under up to three regimes reduced germination when the embryonic axis and cotyledon moisture content fell below 55 to 50 % and 45 and 40 % respectively; little or no germination occurred after dehydration to 20 to 30 % embryo moisture content. The results indicate that the frequently encountered desiccation intolerance in Inga embryos may be associated with critically-low levels of specific soluble carbohydrates in their tissues

The seeds of eight herbaceous plant species were embedded in different orientations 2 mm below the surface of uniform agar. This was used to test whether seed orientation had any effect on germination without any physical heterogeneity in the germination medium. Seeds of Aster novae-angliae L., Cichorium intybus L., Daucus carota L., Galinsoga ciliata (Raf.) Blake and Potentilla recta L. showed less germination when the radicle was pointing vertically downward compared with other orientations. Orientation also affected the rate of germination of Galinsago ciliata and Cichorium intybus. Seeds of Lycopus unifloris Michx. and Erysmium cheiranthoides L. were not influenced by orientation. Seeds of Sonchus arvensis L. germinated poorly when buried, compared to surface-lying seeds. Responses of germination to seed orientation may reflect variation in the effects of gravity on the embryo depending on its position. Alternatively, uneven exposure to oxygen and light levels could have influenced results if different regions of the seed coat vary in their sensitivity to these factors. The results indicate that the experience of the environment for an individual seed can depend entirely on its orientation (which may occur by chance), even within a substrate that is completely homogeneous. This distinction of the roles of chance and environmental variation suggests the possibility that differences in success between neighbours within natural vegetation may not always be a consequence of either genetic or background environmental variation.

According to prof. E. Haller, a yield depends in the first place on the environmental conditions during the germination period of seeds. Germination of seeds and development of a root system depend above all on the soil conditions - bulk density, solidity and porosity. A high yield is greatly dependent on the root system. In thickened and rapidly thickening soils a normal root development is disturbed by mechanical resistance of a soil and its poor aeration. In thick soils the roots can normally develope only in cavities left by the roots of preliminary crops. The bulk density of 1.2 cm (-3)...1.4 g cm (-3) is considered to be the optimum for the growth of grain crops. In thicker soils the normal development of roots is hindered and it results in a lower yield. The results of the field experiments showed that with minimization less intensive tillage produces environment more favourable for germination of seeds than in the case of traditional technology. Combined soil tillage and use of sowing aggregate enable us to create the best physical conditions for seed germination. The positive effect of local fertilizing on the yield is widely known. But its co-effect the loosening of the soil between the rows - on the grain crop has not been studied yet

Hand pollinations are frequently used to assess the postpollination success of different donors. We present evidence that the method used for hand pollinations can alter pollen germination rates and paternity of the resulting seeds. Two commonly used methods for hand pollination experiments are mixed pollinations, where pollen from several donors is physically mixed together, and adjacent pollinations, where pollen from one donor is close to, but not in physical contact with, pollen from other donors. These methods offer differing opportunities for pollen interaction, and for females to choose among mates. We found that the success of pollen donors in multidonor pollinations varied with pollination method in unpredictable ways across maternal plants. Pollen germination was significantly lower in adjacent pollinations, perhaps explaining some of the effects of pollination method on paternity. These results may yield insights on the factors influencing pollen success, and indicate that hand pollination experiments should employ pollination methods that mimic as closely as possible the natural arrival of pollen in nature.

The interspecific differences in germination, root nodule formation, dry matter production and nitrogen uptake were evaluated among Crotalaria species for the introduction as new green manure legumes. The germination progressed smoothly in C. juncea and C. spectabilis, but physical scarification was necessary in C. pallida. In the field experiment, C. juncea had a high dry weight and a great nitrogen content at the early growing stage, but a drastic defoliation and a high C-N ratio were found at the late growing stage. C. pallida grew slowly at the early stage, but a high nitrogen content and an adequate C-N ratio for decomposition were found at the late growing stage. C. spectabilis showed intermediate traits in dry matter production and nitrogen uptake. In the root-box experiment, the distribution patterns of root systems and root nodules varied among the three species. C. juncea had greater root growth and nodulation compared with two other species at 35 days after sowing. When the three species are introduced to various cropping systems, these traits should be considered for choice as green manures