Ovule seed development

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. 

The flowers of most species have six sepals, arranged in two cycles. Sepals are the outermost whorl of a flower, typically leaf-like in appearance. The stamens, or male organs, of laurel flowers occur in three or four cycles, with three stamens in each. The flowers usually have a single pistil, or female organ, which contains a single ovule that develops into a seed after fertilization. The fruit of most species is aromatic, and is classified as a drupe, in that is has a fleshy outer layer and a hard inner layer with a single seed. 

Pistil—Female reproductive organ of a flower, which contains ovules that develop into seeds after fertilization by pollen. 

Typically, there are 20 30 ovules in a boll containing three to five segmented compartments (locules). The ovules are attached to the plant via a connection called the funiculus. Fertilization of the ovules is essential for subsequent development of the seed and fiber. When there is a failure in the fertilization of a seed, development is aborted and the resulting mote may cause problems during later fiber and fabric processing steps. It is possible to remove unfertilized ovules from the boll and mimic the conditions for seed and fiber growth in tissue... 

Barlow PW, Macdonald PDM (1973) An analysis of the mitotic cell cycle in the root meristem of Zea mays. Proc Roy Soc Lond B 183 385-398 Basrur SV, Fletcher RA, Basrur PK (1976) In vitro effects of 2,4-dichlorophenoxy acetic acid (2,4-D) on bovine cells. Can J Comp Med 40 408-415 Batra MW, Edwards KL, Scott TK (1975) Auxin transport in roots Its characteristics and relationships to growth. In Torrey JG, Clarkson DT (eds) The development and function of roots. Academic Press, London New York, pp 299-325 Beasley CA, Ting IP (1973) The effects of plant growth substances on in vitro fiber development from fertilized cotton ovules. Am J Bot 60 130-139 Beasley CA, Ting IP (1974) Phytohormone effects on in vitro cotton seed development. 

Another problem is the direction of pollen tube growth, which should be considered as tropism, related to attraction by the fertile ovules. Many observations of pollen tubes in the fluorescence microscope supported this suggestion—pollen tubes pass by the sterile ovules and grow in the direction of the fertile ones. The number of ovules penetrated by a pollen tube is correlated with the number of developing seeds, which supports the hypothesis about interaction (attraction) between the ovule and pollen tube (1,2,5). 

Seed The small bodies produced by spermatophytic plants containing embryos capable of developing through germination a fertilized and ripened ovule. 

Variations of the life cycle occur. For example, a process called apomixis leads to asexual formation of seed.469 In many plants, including maize, separate flowers form the ovule and the pollen. This is one mechanism for avoiding inbreeding.470 In many plants systems of self-incompatibility have evolved.471 In some, e.g., Arabidopsis and other crucifers, pollen germination is disrupted unless it falls on a stigma possessing a different allele-specific receptor. In other cases development of the pollen tube is disrupted at a later stage. In maize and in more than 150 other... 

A nut is a simple fruit, in that it is derived from the pistil of a single flower. Although a nut contains only one seed, the flower from which it develops has a compound ovary, with many ovules (immature and unfertilized seeds). Following fertilization, the other ovules of the flower undergo spontaneous abortion and die. 

In the more benign asexual cycle, Epichloe endophytes (and all Neotyphodium species) remain asymptomatic (Fig. 1). As floral primordia are formed, endophytes grow into ovules, proliferate in the nucellus tissues, and later colonize the embryonic axis of the developing seed, which leads to vertical transmission (Freeman, 1904 Philipson and Christey, 1986). Hyphae in the remnant nucellar layer form a conspicuous mat between the aleuron and the seed coat (White et al., 1991). Symptomless endophytes may also invade stamen filaments and anther walls, but have never been found in pollen grains, and apparently are not disseminated via paternal structures (Sampson, 1933 Hinton and Bacon, 1985). Vertical transmission of endophytes in infected tillers occurs at nearly 100% efficiency (Siegel et al., 1984). However, seeds which are free of endophyte may occasionally be produced when shoot meristems of individual... 

The calyx and corolla show abundant alkaloids in the epidermis. The anthers possess them in the epidermis, the tapetal layers around the developing pollen sacs, and in the bundle sheath of the filament, but not in the vascular elements themselves. Carpels and ovules contain abundant alkaloids in all parts. During the development of the ovule into a seed, its alkaloids diminish and at the resting stage are confined to a single layer of crushed cells on the inside of the testa. The embryo itself and the endosperm are both devoid of alkaloid. The ripe berry has abundant alkaloid in the epidermis, mesocarp, and placenta. 

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