Gross Nutritional Contributions of Maize Endosperm and Scutellum to Germination Growth of Maize Axis

Abstract

In 1890 Brown and Morris (8) showed that starch paste, when applied to the absorbing surface of the scutellum, could replace the endosperm during the germination of barley embryos. Andronescu (2) first demonstrated that the maize embryo (axis & scutellum) could develop into a normal plant when separated from its endosperm and supplied with sucrose. Most investigators, however, have emphasized the endosperm as a source of growth factors, either essential or stimulatory to the germination of the axis, rather than as a tissue serving singularly as a source of sugars and inorganic ions. Schander (26) considered the aleurone layer of the maize endosperm to be the source of an accelerator which is absorbed by the scutellum during germination. DeRopp (i l) found that embryos which were allowed to remain in the intact grain during the early stages of germination exhibited more vigorous growth after excision than did embryos removed from the dry rye seed. He also interpreted this as due to the absorption by the scutellum early in germination of a growth factor from the endosperm. The "Z" factor of Robbins (25) and the "blastinin" hormone of Cholodny (10) are other compounds said to originate in the endosperm. The high percentage of bound auxin residual in the resting endosperm of maize (3,4,7,13,14), and the increasing discoveries of gibberellin-like substances in the seeds of higher plants (22,24) also have made the contribution by the endosperm to the growth of the axis seemingly more complex than merely that of a sugar and inorganic ion source. Furthermore, Nason (19) found that the rate and extent of niacin accumulation in intact maize embryos were three times as great as that of excised embryos after 10 days of germination. His data suggest that this is related to the absorption of tryptophan from the endosperm rather than to the absorption of niacin itself.The extent to which the scutellum can provide nutrition to the axis has received little attention, although it has been shown that lipids are rapidly lost from the maize scutellum during germination (18). 'Received May 9, 1960. 2 Research supported by National Science Foundation under NSF grant G6076.3 Present address: Department of Chemistry, University of Georgia, Athens.The object of this research was to determine the relative nutritional contributions of the scutellum and the endosperm of the maize kernel to the growth of the axis during germination. METHODS AND MATERIALSThe material used was a non-waxy, inbred maize (Zea mays L.) line T854, secured from the Agricultural and Mechanical College of Texas. The endosperm of this line contain 85 % carbohydrate and 10 % protein on a dry weight basis (12). Oil is present in trace amounts in the aleurone layer, demonstratable by staining with Sudan IV. The predominate carbohydrates found in non-waxy maize endosperm during germination are starch, maltose, dextrins of various chain lengths, and a trace of glucose (29,6). Amylose comprises about 25 % of the starch of non-waxy maize endosperm and the remainder is...

On the relative role of the scutellum and aleurone in the production of hydrolases during germination of barley

“…The relative role of these two tissues in the synthesis and dissemination of hydrolytic enzymes has been a subject of much discussion for a period of almost one hundred years (3,9,11,16,20,25). A variety of experimental techniques have been utilised in attempts to elucidate the relative contributions of both tissues: dissection followed by incubation in the presence of either plant hormones (7,18,19) or an ,endospermlike~ substrate (10); inflicting lesions to the one tissue and thereafter measuring the contribution of the other (2); simple histochemical observation of thin sections (5,16,20,25).…”

“…It is well established that in barley caryopsis both the scutellum and the aleurone layer are involved in the production and mediation of hydrolytic enzymes during germination (4,5,9,10,16,20,25).…”

Dependence of Seed Vigor during Germination on Carbohydrate Source in Endosperm Mutants of Maize

“…Carbohydrate hydrolysis in the endosperm is not initiated for at least the first 48 h of germination (13); soluble sugars in the embryo may be quickly used (24) as may be lipids (7) and proteins (15). This demonstrates the importance of stored reserves in the embryo for early seedling growth.…”

Physiological and ultrastructural investigations of caryopsis dormancy in Setaria lutescens (Gramineae)

“…In contrast, much less attention has been paid to the function of the glyoxylate cycle during germination of Gramineae caryopses. Although the develop mental pattern of glyoxysomes in the Gramineae appears similar to that in oleaginous species (Longo and Longo, 1970a;Longo, Bernasconi, and Longo, 1975;Longo and Longo, 1970b), the total lipid loss is typically not as great (Dure, 1960;MacLeod and White, 1961;Ingle, Beevers, and Hageman, 1964;and Tavener and Laidman, 1972a) as in oleaginous seeds (Ching, 1970;Muto and Beevers, 1974). In addition, other evidence suggests that, during germination, the Krebs cycle plays a greater role in the assimilation of the end-products of 6-oxidation in the Gramineae than occurs in oleaginous seeds (Oaks and Beevers, 1964;Effer and Ranson, 1967).…”