Seeds conditioning

Hsiao, A. I., Warshem, A. D., and Moreland, D. E. 1988. Effect of chemicals often regarded as germination stimulants on seed conditioning and germination of witchweed (Striga asiatica). Ann. Bot. 62, 17-24... 

When the seeding conditions are optimized, the generated SH signal is clearly visible on a white screen. In the case of a 0.3 pm thick film of the DRl-MMA 35/65, it is found that after saturation, the intensity ratio between the 2co generated generated beam 12 and the 2co seeding beam /2a... 

Crystalline processes often provide a seed bed for crystal growth with an initial nucleation step. When attempting to control particle size and shape, an excessive number of nuclei can effectively make it impossible to achieve the desired size or morphology. Optimal processes with externally or internally (heel) added seed often require some level of seed conditioning. Principles for such conditioning are discussed in Chapter 5 and in some of the examples. 

In a third example, when a compound was initially tested in a microsomal stability assay, no metabolism was observed, with 100% of the compound remaining after a 15-min incubation. When it was retested under the same conditions, only 50% remained after 15 minutes. The results were irreproducible and erratic. The reason was that the compound had poor aqueous solubility. It precipitated during the first dilution into the aqueous media (Dilution is essential to reduce the DMSO content, because it inhibits Cytochrome P450 activity). The solid precipitate was not metabolized, but it was quantitated in the assay when acetonitrile was added to the aqueous reaction mixture. The compound, thus, appeared artificially to be more stable. Precipitation is quite a variable process and depends on many different factors, such as temperature, incubation time, seeding conditions and agitation. The completeness of precipitation affects the final results, thus, assay results tend to be more variable for insoluble compounds. 

Figure 4.37 shows the morphology of two [TTF][Ni(dmit)2]2 films grown on silicon. The difference between the two deposits originates from both the applied current density and the surface morphology of the silicon substrate which induces different seeding conditions. 

Table I. Germination of Witchweed Seeds Conditioned in Water at 30°C for 7 and 14 Days Followed by 24-h Terminal Treatment with Brassino-lide, d/-Strigol, and Natural Stimulants at 30°C in the Dark ...

Figure 1. Germination of Witchweed Seeds Conditioned in Water and Brassinolide (10 7M) for 3-7 Days before Terminal Treatment with Natural Stimulants. Bars Represent Standard Errors of Means for 3 Replications over 3 Experiments.

Table V. Germination of Witchweed Seeds Conditioned in Various Plant Growth Regulators at 30°C for 7 Days with and without Terminal Treatments of Natural Stimulants (4-fold Diluted) from Sorghum at 30°C Conditioning media Germination (%)...

Table VII. Percent Germination of Witchweed Seeds Conditioned in the Combination of rf/-Strigol (ST) with Brassinolide (BR) at 30°C for 7-15 Days Followed by 24-h Terminal Treatments with d/-Strigol (10 7M) at 30° C...

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