Structure of the seed

Plants are also classified as dicotyledons and monocotyledons according to the stracture of the seed. 

A good example of a dicotyledon seed is the field bean. If its pod is opened when nearly ripe it will be seen that each seed is attached to the inside of the pod by a short 

If a bean is soaked in water the seed coat can be removed easily and all that is left is largely made up of the embryo (germ). This consists of two seed leaves (cotyledons) which contain the food for the yoimg seedling. Lying between the two cotyledons is the radicle (which eventually forms the primary root) arrd a continuation of the radicle at the other end, the plirmule (Fig. 1.6). This develops into the young shoot and is the first bud of the plant. 

Most of the interior of the grain is taken up by the floury endosperm. The embryo occupies the small raised area at the base. The scutellum, a shield-like stractirre, separates the embryo from the endosperm. Attached to the base of the scutellirm are the five roots of the embryo, one primary and two pairs of secondary rootlets. The roots are enclosed by a sheath called the coleorhiza while the shoot is enclosed by the coleoptile. The position of the radicle and the pliunule can be seen in Fig. 1.7. The scutellirm can be regarded as the cotyledon of the seed. There is only one cotyledon present and so wheat is a monocotyledon. 

When the leaves of the plant begin to manufacture food by photosynthesis, and when the primary root has established itself sufficiently well to absorb nutrients from the soil, the plant can develop independently, provided there is sufficient moistnre and air present in the soil, and conditions above ground are suitable for growth. 

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The concentrated mother liquor contains a laige amount of sulfuric acid in a free form, as titanium oxy-sulfate, and as some metal impurity sulfates. To yield the purest form of hydrated Ti02, the hydrolysis is carried out by adding crystallizing seeds to the filtrate and heating the mixture close to its boiling temperature, 109° C. The crystal structure of the seeds (anatase or rutile) and their physical properties affect the pigmentary characteristics of the final product. 

Nevertheless, it is clear that any anisotropic - growth that results from the preferential binding of organic species to certain crystal faces relies on the crystal structure of the seed nanoparticles. Whether the seeds are single crystalline or whether they possess any twin planes or other defects, will determine the type and orientation of the crystal faces that are exposed to the growth medium in the first place. This is all the more apparent when we consider that in most syntheses a range of particle shapes are observed and yet the same shaped particle can be the major product of very different syntheses. 

FIGURE 1.17 Structure of the seed tests of the Washington lupine Lupinm polyphyllm Lindl.). 40... 

An unknown acetylenic ammo acid obtained from the seed of a tropical fruit has the molec ular formula C7H11NO2 On catalytic hydrogenation over platinum this ammo acid yielded homoleucme (an ammo acid of known structure shown here) as the only product What is the structure of the unknown ammo acid" ... 

The nature of the deposit and the rate of nucleation at the very beginning of the deposition are affected, among other factors, by the nature of the substrate. A specific case is that of epitaxy where the structure of the substrate essentially controls the structure of the deposit.Plb lP ] Epitaxy can be defined as the growth of a crystalline film on a crystalline substrate, with the substrate acting as a seed crystal. When both substrate and deposit are of the same material (for instance silicon on silicon) or when their crystalline structures (lattice parameters) are identical or close, the phenomena is known as homoepitaxy. When the lattice parameters are different, it is heteroepitaxy. Epitaxial growth cannot occur if these stmctural differences are too great. 

On comparing the two flames, it is evident that the flow structure of the lean limit methane flame fundamentally differs from that of the limit propane one. In the flame coordinate system, the velocity field shows a stagnation zone in the central region of the methane flame bubble, just behind the flame front. In this region, the combustion products move upward with the flame and are not replaced by the new ones produced in the reaction zone. For methane, at the lean limit an accumulation of particle image velocimetry (PIV) seeding particles can be seen within the stagnation core, in... 

Yang et al. found that Ag-core/Pt-shell nanoparticles with a core/shell could only be formed by the successive reduction method using Ag nanoparticles as the seeds. Results of measurements of UV-Vis, TEM, EDX, and XPS supported the core/shell structure of the bimetallic nanoparticles. The reverse order of preparation using Pt nanoparticles as the seeds did not provide any core/shell nanoparticles while a physical mixture of Ag nanoparticles and the original Pt seeds was obtained [140]. 

Earlier in this paper studies were reported that indicated correlation of the molecular structure of the compound with bioactivity in seed germination in laboratory tests, as compared to tests performed in the field, offer distinct advantages. Most of what we know on this subject was obtained from laboratory test procedures. Results from field tests are also dependent upon the stability of the compound and physical factors such as solubility and adsorption in the soil. 

Experiment 5. Observation under transmission electron microscope We compared the TEM ultrastructure of the seed coat and endosperm of control and rue-treated seeds The palisade layer of treated seed appears thicker than in the control (Figs 6A and 7A), while comparison between aleuronic cells of the control and treated cells (Figs. 6B and 7B), reveals that the cells of the control are healthy with some evident organelles such as the nucleus and the rough endoplasmic reticulum and other structures, the plastid, the plasmodesmata, conspicous constrictions, protein bodies and... 

Figures 4c and 4d demonstrate OCT images of two seeds out of the GMF group after 60 minutes when turgescence has started. One can distinctly detect darker layers of watered zones and the heterogeneous zones of water absorption. The water absorption zones merged in a united system of microcapillary vessels with sizes 50-10 pm. Individual differences in the structure of the water absorption zones in the seeds are also clearly seen.

Figures 4e and 4f show OCT images of two control seeds after 60 minutes when turgescence has started. Similar to the GMF seeds, individual structural differences of the seeds are clearly visible here. However, after the same time period the heterogeneous absorption zones (Fig. 4f) are less expressed than in the GMF seeds (Fig. 4d). The bright area corresponding to highly scattering regions (Fig. 4d) is narrower (about 100 im) in the control than in GMF seeds (about 200 pm). Thus OCT imaging of barley seeds can distinctly visualize water absorption processes within the first hour, as well as, individual variations in different seeds. The variations reflect the phenomenon of biological variability of seeds at the tissue level.

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