The Development of Cells in the Growing Zones of the Root

Brown, Rex V.; Broadbent, David

doi:10.1093/jxb/1.3.249

Cited by 130 publications

(25 citation statements)

References 9 publications

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“…While the location of various structural regions of the barley roots varied but little, the autoradiograms and counts of activity shown graphically in figure 4 indicate that the pattern of p32 concentration varies appreciably.…”

Section: Autoradiogramsmentioning

confidence: 95%

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LONGITUDINAL GRADIENTS OF P³² ABSORPTION IN ROOTS

Kramer

Wiebe

1952

Plant Physiol.

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It is generally agreed that the greatest accumulation of ions occurs in the cells near the tips of the roots. PREVOT and STEWARD (17) observed that accumulation of bromide ions by excised barley roots was greatest in the apical centimeter ; and STEWARD et al. (20) found that accumulation of potassium by roots of intact barley seedlings and of rubidium by excised roots 5 cm. in length increased progressively toward the tip and was greatest in the shortest segments analyzed (0.5 cm.). Experiments of OVERSTREET and JACOBSON (16) indicated that at 00 C maximum absorption of radioactive rubidium and phosphorus by apical segments of barley roots 1 cm. in length occurs within a millimeter of the tip. JACOBSON and OVERSTREET (7) later reported that maximum absorption of radioactive iodine and strontium occurs within 2 or 3 mm. of the root tip. STEWARD (19) has described in summary form work carried out in his laboratory in conjunction with Drs. R. Overstreet and S. M. Caplin. The accumulation of Cs137 in roots was studied by means of autoradiograms and by measuring the radioactivity of 1-mm. segments at intervals of 1 or 2 mm. from the apex to 10 cm. behind the apex. The published autoradiograms and counts show puzzling irregularities in accumulation along a single root and differences between roots from the same plant that could not be related to structure or physiological condition of the tissues.While studying p32 absorption of pine roots, the authors obtained a number of autoradiograms. These showed that, as expected, there was usually heavy accumulation in the root tips and lower accumulation a few millimeters behind the root tip. Unexpectedly, however, a number of roots showed other regions of high accumulation extending some distance behind the tips. A typical example of this accumulation was shown in figure 2a of KRAMER and WILBUR (9). Since many examples of this unexpected pattern of accumulation were observed, further study was made to find how extensively it occurs. Efforts were also made to find what relations exist between dry weight, total nitrogen content, total phosphorus content, and radioactive phosphorus content of root segments at various distances behind the root apex.Experiments and results The pine roots used in this study were obtained from loblolly pine seedlings growing in pots in a cold frame. The tomato roots were adventitious roots produced on cuttings grown in aerated Hoagland's solution containing

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Section: Autoradiogramsmentioning

confidence: 95%

“…in length to permit more accurate localization of the regions of high and low absorption. The averages of three sets of such measurements are summarized graphically in figure 4. Below the counts is shown a diagram indicating the approximate location of various regions of a barley root.…”

Section: Autoradiogramsmentioning

confidence: 99%

LONGITUDINAL GRADIENTS OF P³² ABSORPTION IN ROOTS

Kramer

Wiebe

1952

Plant Physiol.

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“…Stclh a mletabolisnm in roots is to be found( in the decreasing amiiount of mlicrosomal RNA and the increasing amouint of RNA associated w!ith miitoclhondrial andl membranous mlaterial (luring cell growtlh (18). Part of this latter RNA miay be that which is essential to respiration an(l ion accumulation, aii(l nday contribute to the increase in respiration anlle ion accumulatioln per unit protein known to occur with root cell expansion (3,4,14,18,28 (8).…”

Section: 'Lant Physiologymentioning

confidence: 99%

Impairment of Respiration, Ion Accumulation, and Ion Retention in Root Tissue Treated with Ribonuclease and Ethylenediamine Tetraacetic Acid

Hanson¹

1960

Plant Physiol.

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“…Results often depend on whether studies on cell expansion were done with intact plants or with excised parts. A net increase in protein content is usually associated with intact cell extension (6,15,17,30), while excised tissues usually show a net decrease (9,18,30,33). A possible exception to the latter phenomenon was reported by Thimann and Loos (32) for excised potato and artichoke tissue.…”

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confidence: 96%