The alfalfa leafcutting bee (Megachile rotundata) is solitary and managed on a large scale for pollination of alfalfa seed crops. The bees nest in holes drilled in wood or polystyrene blocks, and their larvae are highly prone to a fungal disease called chalkbrood. The most prevalent form of chalkbrood is caused by Ascosphaera aggregata, but this ascomycete is difficult to culture. Hyphae will grow on standard fungal media, but spore germination is difficult to achieve and highly variable. We found that germination can be enhanced with oils. Lipids derived from plants and bee larvae increased germination from 50% (without oil) to 75-85% (with oil). Percent germination was significantly greater in the presence of lipids but germination was not significantly different when different oils, including mineral oil, were used. A. aggregata spores oriented along the oil--aqueous interface in the broth in a polar fashion, with swelling and germ tube formation always occurring into the aqueous portion of the broth. The other half of the spore tended to attach to a lipid droplet, where it remained, without swelling, during germ tube formation. The physical attachment of spores to the oil--aqueous interface is what most probably stimulates spore germination, as opposed to some nutritional stimulation. However, further research is needed to determine if and where the spores encounter such an interface when germinating in the host gut, where germination normally occurs.

We investigated the physical control of seed-borne diseases. Blast, "Bakanae" disease and White-tip Nematode on rice. The infected seeds were immersed into 60degC hot water for 10 minutes using the hot water treatment machine. The hot water immersion showed the effect which is equal to the agricultural chemicals against these diseases. We investigated the influences of hot water treatment on germination. To avoid the decline of the germination percentage, the processing temperature is 60degC, the processing time is 10 minutes. To avoid the decline of the germination percentage, the seed which was produced at previous year must be used. Also, we kept the seeds at the constant temperature for 1 month from the treatment. The treated seeds germinated normally.

Seeds of Gmelina arborea Roxb. were subjected to different treatment [chemical scarification with concentrated sulphuric acid (H2S04), potasium nitrate (KNO3), potasium nitrite (KNO2) and alternating temperature regimes] to ascertain the best treatment for terminating dormancy in the seeds. Initial viability and germination tests showed that the seeds of G. arborea are viable but dormant. Seed viability percentage of 96 was recorded. Dormancy in the seeds was found to be the physical type caused by hard seed coat. Chemical scarification for 10 minutes with concentrated H2S04 was very effective in breaking seed dormancy in the species. This increased water uptake in the seeds to 68% compared with the 15% in unscarified seeds after 7 days. Scarification gave a germination percentage of 80 over 43% for the unscarified after 26 days. 1mM and 10mM KNO3 and KNO2 terminated dormancy and highly enhanced germination in the scarified than unscarified seeds. Alternating temperatures promoted germination of G. arborea seeds with the best results recorded at 9 cycles of alternating temperature at 30 °C for 16hours and 45 °C for 8 hours. Key Words: Dormancy, Gmelina arborea, Chemicals, Alternating temperatureBio-Research Vol.2(1) 2004: 59-66

Five kinds (classes) of seed dormancy are known: physiological (PD), morphological (MD), mor-phophysiological (MPD), physical (PY), and combinational (PY+PD). PD is the most common class in the major vegetation zones of the world followed by PY, MPD, MD, and (PY+PD). Each class is described, and a dichotomous key to identify them is presented. The environmental conditions required to break PD, MD, MPD, PY, and (PY + PD) and promote germination are discussed. To help determine which treatments to use for breaking dormancy in seeds with water-permeable seedcoats (PD, MD, MPD), a "move-along experiment" is recommended. Little or no convincing evidence for the role of microbes or mechanical abrasion by soil particles in breaking PY can be found in the literature. However, there is good evidence that the water plug or gap in the seed or fruit coat of seeds with PY responds to environmental cues that permit timing of imbibition and germination to be well controlled in nature. Seeds of many species remain viable after passing through the digestive tracts of animals, with varying effects on germination.

Escherichia coli and Pseudomonas putida dried in hydroxyectoine or trehalose are shown to be highly resistant to the organic solvents chloroform and acetone, and consequently, they can be encapsulated in a viable form in solid plastic materials. Bacteria are recovered by rehydration after physical disruption of the plastic. P. putida incorporated into a plastic coating of maize seeds was shown to colonize roots efficiently after germination.

The research aimed at determining changes in the values of selected soil physical properties influenced by the treatments operations carried out after spring cereal sowing. In a three-year experiment, the following soil physical properties were determined: soil consistency, dry soil density, soil humidity and capillary porosity. The determination was repeated at two dates (I-at the stage of plant germination, II-at the stage of cereal maturity). Conventional methods were employed. As a result of post-sowing rolling, the values of the studied soil properties increased. The highest values followed from the application of heavy meadow roller. The magnitude of changes depended on soil humidity, the length of the period between application of treatments and the plant development stage. Under the conditions of lower soil humidity and at the end of cereal growing season, the differences in the values of physical properties between treatments decreased markedly

The research aimed at determining changes in the values of selected soil physical properties influenced by the treatments operations carried out after spring cereal sowing. In a three-year experiment, the following soil physical properties were determined: soil consistency, dry soil density, soil humidity and capillary porosity. The determination was repeated at two dates (I – at the stage of plant germination; II – at the stage of cereal maturity). Conventional methods were employed. As a result of post-sowing rolling, the values of the studied soil properties increased. The highest values followed from the application of heavy meadow roller. The magnitude of changes depended on soil humidity, the length of the period between application of treatments and the plant development stage. Under the conditions of lower soil humidity and at the end of cereal growing season, the differences in the values of physical properties between treatments decreased markedly.