Elimination of Geotropic Responsiveness in Roots of Cress (<i>Lepidium sativum</i>) by Removal of Statolith Starch

Iversen, Tor‐Henning

doi:10.1111/j.1399-3054.1969.tb09115.x

Cited by 87 publications

(44 citation statements)

References 14 publications

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“…In spite of substantial interest in the biochemistry of starch biosynthesis and degradation (21), the effects of starch on photosynthesis (11,28), stomatal function (19), and gravitropism (14), there have been no previous studies employing a mutant lacking leaf starch. The mutants described here were relatively easy to isolate by direct screening, and mutations at two loci have been isolated.…”

Section: Discussionmentioning

confidence: 99%

Alterations in Growth, Photosynthesis, and Respiration in a Starchless Mutant of Arabidopsis thaliana (L.) Deficient in Chloroplast Phosphoglucomutase Activity

Caspar¹,

Huber²,

Somerville³

1985

Plant Physiol.

491

561

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(12,23,28).The effect of carbohydrate accumulation on the rate of dark respiration has received less attention but appears to have been consistently observed by a variety of approaches (2,6,29). The essential observation is that the rate of respiration is proportional to carbohydrate content or is stimulated by provision of exogenous carbohydrate. The implication is that the amount of respiration is regulated by substrate supply rather than demand for ATP or reducing equivalents. Indeed, it has been suggested that, under conditions of high carbohydrate supply, a substantial proportion of the reductant generated during carbohydrate catabolism may be consumed by the alternative oxidase without being linked to ATP production (3,15

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Section: Discussionmentioning

confidence: 99%

Alterations in Growth, Photosynthesis, and Respiration in a Starchless Mutant of Arabidopsis thaliana (L.) Deficient in Chloroplast Phosphoglucomutase Activity

Caspar¹,

Huber²,

Somerville³

1985

Plant Physiol.

491

561

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“…1). The structure of starch statoliths in grass shoots as examined by means of LM,2 SEM, and TEM (9, 19-21, 23, 26), as well as their purported function as gravisensor organelles (1, 14,17,22,25,27), have been studied extensively. Furthermore, it has been shown that these organelles descend within the presentation time (1-2 min) for initiation of an upward bending graviresponse in the grass shoot pulvinus (21).…”

mentioning

confidence: 99%

Do Starch Statoliths Act as the Gravisensors in Cereal Grass Pulvini?

Song

Lu²,

Brock³

et al. 1988

Plant Physiol.

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To determine if starch statoliths do, in fact, act as gravisensors in cereal grass shoots, starch was removed from the starch statoliths by placing 45-day-old intact barley plants (Hordeum vulgare cv 'Larker') in the dark at 25°C for 5 days. Evidence from staining with I2-KI, scanning electron microscopy, and transmission electron microscopy indicated that starch grains were no longer present in plastids in the pulvini of plants placed in the dark for 5 days. Furthermore, gravitropic curvature response in these pulvini was reduced to zero, even though pulvini from vertically oriented plants were still capable of elongating in response to applied auxin plus gibberellic acid. However, when 0.1 molar sucrose was fed to the dark pretreated, starch statolith-free pulvini during gravistimulation in the dark, they not only reformed starch grains in the starch-depleted plastids in the pulvini, but they also showed an upward bending response. Starch grain reformation appeared to precede reappearance of the graviresponse in these sucrose-fed pulvini. These results strongly support the view that starch statoliths do indeed serve as the gravisensors in cereal grass shoots.Recent studies in our laboratory (19-21) have been concerned with the cereal grass leaf-sheath pulvinus as a graviresponsive organ system and whether or not the starch-containing plastids in pulvinus cells of this system are indeed the gravisensors (statoliths). The young, undifferentiated grass shoot pulvinus does not possess any starch-containing statoliths, and it shows no upward bending curvature response when oriented horizontally (9,21,29). However, when the pulvinus is mature, starch statoliths are present in statenchyma cells along the inside of each of the longitudinally oriented vascular bundles, as seen in transverse sections of the pulvinus (Fig. 1). The structure of starch statoliths in grass shoots as examined by means of LM,2 SEM, and TEM (9, 19-21, 23, 26), as well as their purported function as gravisensor organelles (1,14,17,22,25,27), have been studied extensively. Furthermore, it has been shown that these organelles descend within the presentation time (1-2 min) for initiation of an upward bending graviresponse in the grass shoot pulvinus (21). Even so, and in spite of all previous work, we still have no definitive proof that starch statoliths are the gravisensors that trigger an upward bending response in prostrated cereal grass shoots. In other graviresponsive systems, such as in rootcaps of starch-free Arabidopsis mutants, they are not required (7,25); that is, the roots respond to gravistimulation to the same extent as do nonmutant plants, with starch statoliths present in the root ' Supported by National Aeronautics and Space Administration grant NAGW-34.2 Abbreviations: LM, light-microscopy; SEM, scanning electron microscopy; TEM, transmission electron microscopy.caps.In light of the above, we set out to determine whether or not gravitropic curvature could occur in barley shoots in the absence of starch in the pulvinus pla...

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“…Beaucoup d'auteurs (Audus 1962, 1964, Juniper et al 1966, Iversen 1969 et French 1970, Iversen et Larsen 1971, Hestnes et Iversen 1978, Sievers et Schmitz 1973, Haberkorn 1974, Perbal 1974, 1978, Perbal et Perbal 1976, Sievers et Volkmann 1972, Wilkins 1966, Pilet 1971 ont etudie les cellules centrales de la coiffe car elles jouent un role important daps la perception de la gravite. Ces cellules, ou statocytes presentent une structure polarisee organisee le long d'un axe parallele a la direction de la gravite ( Fig.…”

Section: Les Cellules De La Coiffe Des Racinesunclassified

“…1961, Northcote et Pickett-Heaps 1966, Juniper et Roberts 1966. Dauwalder et al 1966, 1969, Harris et Northcote 1970, Rougier 1971, Goff 1973, Dexheimer et al 1978.…”

Section: Les Cellules De La Coiffe Des Racinesunclassified

Sur l'expression ultrastructurale de la differenciation des cellules vegetales.

Dexheimer¹

1983

CYTOLOGIA

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Elimination of Geotropic Responsiveness in Roots of Cress (Lepidium sativum) by Removal of Statolith Starch

Cited by 87 publications

References 14 publications

Alterations in Growth, Photosynthesis, and Respiration in a Starchless Mutant of Arabidopsis thaliana (L.) Deficient in Chloroplast Phosphoglucomutase Activity

Alterations in Growth, Photosynthesis, and Respiration in a Starchless Mutant of Arabidopsis thaliana (L.) Deficient in Chloroplast Phosphoglucomutase Activity

Do Starch Statoliths Act as the Gravisensors in Cereal Grass Pulvini?

Sur l'expression ultrastructurale de la differenciation des cellules vegetales.

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