Seed, development

While studies on the development of embryos from undifferentiated cells in tissue culture have been very useful in revealing some of the information needed to understand the impact of localized environmental factors required to probe 

It can be predicted from tissue culture studies that auxins must be increasing in amount as the embryo initiates the root primordium and we might expect a surge of cytokinins as the stem primordium is initiated (Skoog and Miller 1957). However, clean-cut correlations have not been made in naturally developing seeds. 

Cytokinin levels also change during seed development. In Zea mays (Miller 1967) and Triticum aestivum (Wheeler 1972), for example, it was found that 

Symbols in b total gibberellins, o--o liquid endosperm, ---- embryo total auxins  

A-----A liquid endosperm, a----a embryo total abscisic acid --- liquid endosperm, 

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Neth. Appl. 7,707,944 (j an. 18, 1978) (to National Seed Development Organisation Ltd., East Mailing Research Station). 

Hable, W.E., Oishi, K.K., and Schnmaker, K.S., Viviparons-5 encodes phytoene desaturase, an enzyme essential for ahscisic acid (ABA) accnmnlation and seed development in maize, Mol. Gen. Genet. 257, 167, 1998. 

Agrochemicals from Natural Products, edited by C. R. A. Godfrey Seed Development and Germination, edited by Jaime Kigel and Gad Galili Nitrogen Fertilization in the Environment, edited by Peter Edward Bacon Phytohormones in Soils Microbial Production and Function, William T. 

Palmer Amaranth Extracts. The aqueous extracts made from senescent Palmer amaranth leaves and thyrses after seed development and dispersal had little effect on any of the seeds tested (Table II). 

The expression profile of the USP promoter was monitored under field conditions using a-amylase activity as a reporter. The earliest sign of a-amylase activity was observed 8 DAP. Although the absolute level remained low, a -10-fold increase in promoter activity was detected between 12 and 13 DAP. The activity steadily increased during seed development reaching maximum levels of about 6000 CU kg-1 in mature seeds (Fig. 12.2). 

Fig. 12.2 Enzyme activity during pea seed development under field conditions.

LOXs are normally present in the seeds of plants, although LOXs do not have a clear physiological role in seed development, because no negative effects on crop performance were observed in LOX-deficient seeds as compared with a normal line. For this reason, the possible function of seed LOXs as storage proteins is considered. 

Debeaujon, I. et al., Proanthocyanidin-accumulating cells in Arabidopsis testa regulation of differentiation and role in seed development. Plant Cell, 15, 2514, 2003. 

Figure 32-8 (A) The life cycle of a flowering plant with emphasis on egg-cell formation and seed development. (B) Some further details of embryo development. T, terminal cell B, basal cell C, cotyledon A, axis SC, seed coat En, endosperm EP, embryo proper S, suspensor SM, shoot meristem Pd, protoderm RM, root meristem. From Goldberg et al.i66 with modification.

Seed development in Tokay is normally complete in a high percentage of ovules. Clusters were emasculated to determine whether KGA3 or 4-CPA will induce berry formation in the absence of pollination and fertilization. 

Tsukamoto C, Shimada S, Igita K, Kudou S, Kokubun M, Okubo K, Kitamura K. 1995. Factors affecting isoflavone content in soybean seeds Changes in isoflavones, saponins, and composition of fatty acids at different temperatures during seed development. J Agric Food Chem 43 1184-1192. 

To date very little is known of the regulation of the gln-a gene. This gene must be expressed strongly during seed development as its mRNA is present at quite high levels in both the cotyledons and embryonic axis of dry seeds and is the predominant or perhaps only GS mRNA present in... 

Harada, J.J., De-Lisle, A.J., Bakden, C.S. Crouch, M.L. (1989). Unusual sequence of an abscisic acid-inducible mRNA which accumulates late in Brassica napus seed development. Plant Molecular Biology 12, 395-401. 

Pongratz W, Nograsek A, Endler PC. 1998. Highly diluted agitated silver nitrate and wheat seeding development. Effect Kinetics of a process of successive agitation phases. In High dilution... 

Wobus U, Weber H. 1999. Sugars as signal molecules in plant seed development. Biol Chem 380 937-944. 

Hannah LC. In Larkins BA, Vasil IK, eds. Advances in Cellular and Molecular Biology of Plants, Seed Development. Vol. IV Dordrecht, The Netherlands Kluwer Academic Publishers 1997. 

Sivak MN, Preiss J. In Kigel J, Galili G, eds. Seed Development and Germination. New York, NY Marcel Dekker 1995 139-168. 

The corn kernel is a one-seeded fruit classified as a grain,22 borne on a female inflorescence commonly known as the ear. Each ear is comprised of a central stem, the cob, on which up to 1000 seeds develop. The seeds (kernels) mature about 60 days after pollination and are harvested in late summer or early fall (in the northern hemisphere) when kernel moisture content has dropped below 30% (wet weight basis). 

A common problem in a number of wild Helianthus species is the presence of a seed coat dormancy mechanism. Though at a much lower level, some inhibition can also be seen in cultivated sunflowers. Kamar and Sastry (1974) found that 20-day-old seeds had a substantially higher germination than did more mature seeds (i.e., 30 and 40 days old), indicating the presence of a dormancy mechanism. The onset of dormancy early in seed development is typical of many seed-... 

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