Ultrastructure of Auxin-Induced Tumors of the Coleorhiza-Epiblast of Wheat

Walne, Patricia L.; Haber, Alan H.; Triplett, L.L.

doi:10.2307/2442078

Cited by 7 publications

(4 citation statements)

References 8 publications

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“…On the one hand, the abundance of big lipid or lipid-like globules and of ribosomes, the large amount of organelles specially mitochondria, as well as their division-like figures and irregular shapes, the arrangement of rough ER in extensive parallel arrays, and the presence of disproportionate large nuclei with big nucleoli were also reported in plant tumours (Ames 1972;Burgess and Fleming 1973;Camp and Whittingham 1974;Walne et al 1975) or hyperplasic phloem (Esau and Hoefert 1978). The phenomena are considered as signs of cellular dedifferentiation.…”

Section: Tpn Is Identical To Irreversible Tpd or A Variantmentioning

confidence: 98%

Histo- and cytopathology of trunk phloem necrosis, a form of rubber tree (Hevea brasiliensis Müll. Arg.) tapping panel dryness

Faÿ¹

2011

Aust. J. Bot.

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Abstract. Trunk phloem necrosis (TPN) is a physiological disease of rubber tree (Hevea brasiliensis Müll. Arg.) discovered in the 1980s. It has been distinguished from rubber tree tapping panel dryness (TPD) by its macroscopic symptoms and presumed origin. But little attention has been paid to its microscopic features, and there is now some evidence that both syndromes could be linked to an impaired cyanide metabolism. In order to characterise TPN and compare it with TPD microscopically, the inner phloem of tapping panels was investigated by light and transmission electron microscopy in healthy trees and TPN-affected trees. TPN-affected phloem presented numerous and varied structural and ultrastructural features. There were signs of cellular deterioration in a great number of specialised cells, i.e. laticifers and sieve tubes, and not very specialised cells, i.e. parenchyma cells and companion cells. There were also signs of cellular dedifferentiation in other parenchymatous cells, e.g. in tylosoids and hyperplasic cells. These cells were derived from parenchyma cells that ensheath laticifers in which the latex coagulated. Numerous structural features of TPN are common to TPD, notably tylosoids associated with in situ coagulated latex, which are also known to be early structural markers of TPD and cyanide-induced. It is therefore concluded that TPN is identical to or a variant of TPD, and is a degenerative disease of rubber tree trunk phloem resembling plant stress response, programmed cell death and plant tumourigenesis in some aspects.

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Section: Tpn Is Identical To Irreversible Tpd or A Variantmentioning

confidence: 98%

Histo- and cytopathology of trunk phloem necrosis, a form of rubber tree (Hevea brasiliensis Müll. Arg.) tapping panel dryness

Faÿ¹

2011

Aust. J. Bot.

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“…Earlier studies have proposed that the coleorhiza protects the seminal roots during development and germination, ensuring that the root tip and meristem are protected until they become self-supported (Sargent and Osborne, 1980). The coleorhiza has also been thought to act in conjunction with its hairs in water and nutrient uptake, as a water reserve during dehydration, as a food store (starch and lipid) to support embryo growth before endosperm reserves are mobilized, and in seed anchoring (Nishimura, 1922;Howarth, 1927;Walne et al, 1975;Debaene-Gill et al, 1994). We propose here a new role for the coleorhiza, in which it acts as the key tissue preventing root emergence (germination) in D seeds.…”

Section: Role Of the Coleorhizamentioning

confidence: 99%

Anatomical and Transcriptomic Studies of the Coleorhiza Reveal the Importance of This Tissue in Regulating Dormancy in Barley

et al. 2009

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The decay of seed dormancy during after-ripening is not well understood, but elucidation of the mechanisms involved may be important for developing strategies for modifying dormancy in crop species and, for example, addressing the problem of preharvest sprouting in cereals. We have studied the germination characteristics of barley (Hordeum vulgare 'Betzes') embryos, including a description of anatomical changes in the coleorhiza and the enclosed seminal roots. The changes that occur correlate with abscisic acid (ABA) contents of embryo tissues. To understand the molecular mechanisms involved in dormancy loss, we compared the transcriptome of dormant and after-ripened barley embryos using a tissue-specific microarray approach. Our results indicate that in the coleorhiza, ABA catabolism is promoted and ABA sensitivity is reduced and that this is associated with differential regulation by after-ripening of ABA 8#-hydroxylase and of the LIPID PHOSPHATE PHOSPHA-TASE gene family and ABI3-INTERACTING PROTEIN2, respectively. We also identified other processes, including jasmonate responses, cell wall modification, nitrate and nitrite reduction, mRNA stability, and blue light sensitivity, that were affected by after-ripening in the coleorhiza that may be downstream of ABA signaling. Based on these results, we propose that the coleorhiza plays a major role in causing dormancy by acting as a barrier to root emergence and that after-ripening potentiates molecular changes related to ABA metabolism and sensitivity that ultimately lead to degradation of the coleorhiza, root emergence, and germination.

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“…Previous studies have proposed that the coleorhiza surrounding the radicle provides protection to the quiescent meristematic tissue until the root becomes self‐supported (Sargent and Osborne 1980). Moreover, the coleorhiza is considered as the first organ of the embryo contacting water and nutrient uptake to support embryo growth during germination (Howarth 1927, Price and Ey 1970, Walne et al. 1975, Debaene‐Gill et al.…”

Section: Discussionmentioning

confidence: 99%

QTL mapping of coleorhiza length in maize (Zea mays L.) under two germination environmental conditions

Jiang¹,

Tian²,

Zhu³

et al. 2011

Plant Breeding

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In our present study, using molecular marker technology, we aimed to identify the genetic factors controlling the length of coleorhiza during seed germination based on a population of recombinant inbred lines (RILs) derived from Xinzi517 · B73. The genetic linkage map was constructed with 255 simple sequence repeat markers, which covered 2399 cM of maize genome with an average mapping distance of 9.4 cM. We detected a total of 10 putative quantitative trait loci (QTLs) using composite interval mapping, among which six QTLs were detected on chromosomes 1, 2, 7 and 9 (10°C, 28 day), whereas four QTLs were detected on chromosomes 1, 2, 3 and 9 (25°C, 7 day). The percentage of phenotypic variance (R 2 ) explained by QTL ranged from 5.18 to 16.67 (10°C, 28 day) and 6.73-11.46 (25°C, 7 day), respectively. These results provided the foundation for detecting additional QTL and discovering more favourable alleles for high vigour seed of maize in future study.

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Ultrastructure of Auxin-Induced Tumors of the Coleorhiza-Epiblast of Wheat

Cited by 7 publications

References 8 publications

Histo- and cytopathology of trunk phloem necrosis, a form of rubber tree (Hevea brasiliensis Müll. Arg.) tapping panel dryness

Histo- and cytopathology of trunk phloem necrosis, a form of rubber tree (Hevea brasiliensis Müll. Arg.) tapping panel dryness

Anatomical and Transcriptomic Studies of the Coleorhiza Reveal the Importance of This Tissue in Regulating Dormancy in Barley

QTL mapping of coleorhiza length in maize (Zea mays L.) under two germination environmental conditions

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