The Role of Vitamins and Micronutrient Elements in the Nutrition of the Apical Meristem of Pea Roots.

Torrey, John G.

doi:10.1104/pp.29.3.279

Cited by 63 publications

(10 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition it has been suggested that the metabolites in the root tip region are normally maintained by the supply from other regions of the embryo (3,18,26). If this is true, it is possible that the ready supply of amino acids from older regions of the embryo could control the endogenous synthesis within the tip region as the exogenous amino acids (lo.…”

mentioning

confidence: 99%

The soluble leucine pool in maize root tips.

Oaks¹

1965

Plant Physiol.

View full text Add to dashboard Cite

Experiments with excised maize root tips have shown that an exogenous supply of amino acids can effectively inhibit the synthesis of threonine, valine, leucine, lysine, arginine, and proline from acetate-2-C14 (18). In addition it has been suggested that the metabolites in the root tip region are normally maintained by the supply from other regions of the embryo (3,18,26). If this is true, it is possible that the ready supply of amino acids from older regions of the embryo could control the endogenous synthesis within the tip region as the exogenous amino acids (lo. This prediction would require a reduction of the pool level followed by an increased rate of synthesis of the amino acids after the removal of the transport system. It was therefore the aim of this investigation to define the nature of the soluble pool for a model amino acid in the maize root tip. Since leucine is one of the amino acids potentially supplied in large amounts by the maize en(losperm (21) it was chosen for this purpose. MethodsMaize seed (hybrid var. Wf 9 X 38-11) wvas soaked overnight in water, and allowed to germinate on damp filter paper for an additional 48 hours at 30°. At this time the roots were 4 to 5 cm long. were located on X-ray film, and the material contained was eluted for the determination of radioactivity and a-amnino nitrogen content. When leucine-C'4 was fed, only 1 radioactive area corresponding to leucine was detected on the chromiatogramn. When the residue was exposed to trypsin, or wvas hydrolyzed with 1 N HCI for 48 hours at 250, several radioactive areas were prominent, while the region corresponding to leucine was scarcely visible on the X-ray film. Thus adsorption of C'4-leucine to the residue was not an important source of error.A Kjehldahl digestion followed by nesslerization was used for the nitrogen determinations (11). The a-amino nitrogen was (leterminedl with ninh-drin (28).A balance sheet for the utilization of leucine-U-C'' by excised root tips is shown in

show abstract

mentioning

confidence: 99%

The soluble leucine pool in maize root tips.

Oaks¹

1965

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…Convolvulus arvensis L., obtained from a clone of roots maintained in a modified Bonner-Devirian medium (Torrey, 1954) for a period of 18 years by subculturing root tips and root segments, were used in these ultrastructural investigations. Root tips elongating at a rate of 15-30 mm per day were fixed, dehydrated, and embedded according to the procedures previously described for preparing roots for other studies (Phillips and Torrey, 1971b).…”

Section: Materials and Methods-cultured Roots Ofmentioning

confidence: 99%

The Ultrastructure of the Quiescent Center in the Apex of Cultured Roots of Convolvulus arvensis L.

Phillips¹,

Torrey

1974

American Journal of Botany

Self Cite

View full text Add to dashboard Cite

Cultured roots of the common bindweed, Convolvulus arvensis L. growing at the rate of 15-30 mm/ day in sterile nutrient medium were fixed for electron microscopic analysis. The ultrastructure of the quiescent center, the initials of the ground meristem, and the initials of the procambium were studied in order to determine whether sequential structural changes could be correlated with models for specifying the mechanisms by which cell differentiation and cell division might be controlled. The differentiation of cells in the root proper occurs very gradually in linear files from the site of the quiescent center proximally into the different tissue regions. Major structural changes, such as the orientation and subsequent elongation of cells along the longitudinal axis of the root and cell wall changes, indicate that the control of differentiation and perhaps cell division occurs in radial gradients outwardly from the quiescent center.

show abstract

“…Convolvulus arvensis L., obtained from a clone of roots maintained in modified Bonner-Devirian medium (Torrey, 1954) at 23 C. Cultures were agitated continuously on a horizontal rotary shaker at 80 rpm. Prior to use, root tips were transferred to fresh medium for 3-4 days to determine the approximate rate of elongation.…”

Section: Materials and Methods-cultured Roots Ofmentioning

confidence: 99%

Duration of Cell Cycles in Cultured Roots of Convolvulus

Phillips

Torrey

1972

American J of Botany

Self Cite

View full text Add to dashboard Cite

The durations of the cell cycle in physiologically different regions of the meristem of cultured roots of Convolvulus arvensis were determined by the metaphase-accumulation technique involving colchicine. The cell cycle in the root cap increases from 13 hr in the actively dividing initials of the first tier to 155 hr in the slowly dividing initials of tiers 2-4 to an indeterminate value for derivatives of the initials in the root cap columella. The cycle times for the cells of the central cylinder and cortex are' 21 and 27 hr, respectively. The cells of the quiescent center have a cycle of an estimated 420 hr. The duration of the cell cycle in these different regions is discussed in relation to the increased duration of G, in slowly or non-dividing cells. The possible regulation of cell division by the synthesis of a cell-division factor in the quiescent center is also discussed.

show abstract

The Role of Vitamins and Micronutrient Elements in the Nutrition of the Apical Meristem of Pea Roots.

Cited by 63 publications

References 12 publications

The soluble leucine pool in maize root tips.

The soluble leucine pool in maize root tips.

The Ultrastructure of the Quiescent Center in the Apex of Cultured Roots of Convolvulus arvensis L.

Duration of Cell Cycles in Cultured Roots of Convolvulus

Contact Info

Product

Resources

About