Analytical studies on the shoot apex of <i>Helianthus annuus</i>

Steeves, Taylor A.; Hicks, M. Anne; Naylor, J. M.; Rennie, P. J.

doi:10.1139/b69-195

Cited by 49 publications

(28 citation statements)

References 13 publications

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“…Active mitochondrial biogenesis, however, is not always correlated with mitotic activity, at least in roots (Kuroiwa et al, 1992). In our case, no labeling was observed in the central region of the inflorescence meristem in R-1 inflorescences, which is known to have mitotic activity comparable with that of peripheral zones (Steeves et al, 1969;Marc and Palmer, 1982). It was similar that no specific labeling has been observed in different parts of the vegetative shoot apex, which comprises regions with considerably different mitotic activity (Steeves et al, 1969).…”

Section: Discussioncontrasting

confidence: 56%

“…In our case, no labeling was observed in the central region of the inflorescence meristem in R-1 inflorescences, which is known to have mitotic activity comparable with that of peripheral zones (Steeves et al, 1969;Marc and Palmer, 1982). It was similar that no specific labeling has been observed in different parts of the vegetative shoot apex, which comprises regions with considerably different mitotic activity (Steeves et al, 1969). The increase in transcript abundance must be related to a cell-and/or tissue-specific developmental process, perhaps more related to mitochondrial biogenesis than to mitotic activity.…”

Section: Discussioncontrasting

confidence: 56%

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Cell-Type-Specific Expression of Plant Cytochrome cmRNA in Developing Flowers and Roots

et al. 2001

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We have used RNA in situ hybridization to analyze the expression of transcripts encoding cytochrome c in different tissues and organs of sunflower (Helianthus annuus). Although northern-blot hybridization experiments indicate that the relative abundance of transcripts does not vary greatly, we have detected important changes in localization during flower development. Enhanced expression is observed in floral meristems as soon as they are discernible from the central portion of the capitulum containing the inflorescence meristem. As flowers develop, labeling is observed in all developing floral organ primordia. Later in development, expression in petals is reduced, and only the central portion of the flower becomes labeled. During the process of stamen formation, hybridization signals were obtained mainly in anthers. Less developed flowers at this stage showed expression through the archesporial tissue. During meiosis, the label was observed mainly in tapetal cells. Specific expression patterns, similar to those obtained for sunflower, were observed when Arabidopsis flowers were analyzed with a homologous cytochrome c probe. Specific patterns of expression were also observed in young sunflower roots. In this case, enhanced expression was detected in developing endodermis and pericycle and in protoxylem initials. We conclude that cell-specific mechanisms operate to regulate the abundance of cytochrome c encoding transcripts in different plant tissues. The overlap between the expression patterns of the nuclear encoded cytochrome c gene and some mitochondrial genes suggests the existence of coordinated mechanisms of expression.

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Section: Discussioncontrasting

confidence: 56%

Section: Discussioncontrasting

confidence: 56%

Cell-Type-Specific Expression of Plant Cytochrome cmRNA in Developing Flowers and Roots

et al. 2001

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“…A sharp contrast in the intensity of stain between the midsector and the peripheral sectors was observed more frequently in stage III. The occurrence of such distal cells stained lightly with Feulgen has been reported in the shoot apices of Chenopodium album (Gifford and Tepper 1962a) and Helianthus annuus (Steeves et al 1969) and in the apices of lateral inhibited buds of Tradescantia paludosa (Naylor 1958;Dwivedi and Naylor 1968). In leafy spurge, however, the zonal distribution of DNA that appeared characteristically in stages II and III disappeared in the apices of stage IV (Fig.…”

Section: Histochemical Studiesmentioning

confidence: 60%

“…In a recent article, Steeves et al (1969) have made a critical assessment of the méristème d'attente concept on the basis of their analytical studies on the shoot apex of Helianthus annuus. They have demonstrated in the vegetative apex an unmistakable central region corresponding to méristème d'attente in which there was little or no mitotic activity and DNA synthesis was reduced to a very slow rate.…”

Section: Introductionmentioning

confidence: 99%

Developmental studies on leafy spurge (Euphorbia esula). Histochemical and autoradiographic studies of the adventitious shoot apices

Raju¹,

Ho²

1973

Can. J. Bot.

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Abstract:Analysis of apices at four different developmental stages (progressively older from I to IV) of adventitious shoots of leafy spurge (Euphorbia esula L.) was carried out. In this study, some selected histochemical and autoradiographic techniques were used to study DNA, histone, and RNA changes during vegetative shoot growth. In the early vegetative phases (stages I to III), the DNA distribution and DNA synthesis based on Feulgen stain and thymidine-H 3 incorporation respectively were found to be greater in the peripheral sectors (S 1 and S 3 ) than in the midsector (S 2 ) and consequently the apex showed a characteristic cytozonation. The central zone (S 2 ) showed less DNA staining and the rate of DNA synthesis was slower than that in the peripheral sectors. This central zone, which is often considered as méristème d'attente, cannot be interpreted similarly for there was slow DNA synthesis as indicated by the low incorporation of thymidine-H 3 . It is suggested that the nuclei in S 2 in stages II and III had a longer mitotic cycle than those in S 1 and S 3 . The zonal pattern seen in the early stages disappeared in stage IV. This final stage may be considered as the "intermediate phase" during the transformation of the vegetative apex to the floral apex. The distribution of nucleohistones based on results of alkaline fastgreen staining procedure was similar to that of Feulgen stain for DNA at all four stages. However, when lysine groups in the histone were blocked by acetylation method, the apices showed that the argininerich histone fraction was dominant and uniform in all four stages. This means that in stages II and III, S 2 had less lysine-rich histone fraction than S 1 and S 3 . The nuclei in S 2 in stages II and III had longer mitotic cycle and Page 2 of 17 this was probably due to less lysine-rich histone content. The cytoplasmic RNA observed by following pyronin Y -methyl green staining method and RNA synthesis based on uridine-H 3 incorporation showed no sharp differences among the three sectors of the apex in all four developmental stages. It is interpreted, therefore, that the central zone (S 2 ) in the apex was, although slow, quite active metabolically during the development of the adventitious shoot.

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“…Shoot apices, however, do not readily accept such substances from the environment directly and the supply is generally too attenuated at the shoot apex when given through the roots or cut stem. Ways round this problem include injecting just below the apex (Clowes, 1959), removal ofthe young leaves covering the apex (Bernier and Bronchart, 1963), the use of concentrations of colchicine (Corson, 1969;Lyndon, 1970;Leshem and Clowes, 1972;Bodson, 1975) and of tritium (Gifford, 1960a) likely to upset the meristem, the addition of detergents (Gifford, 1960b), the use of excised apices (Steeves et al, 1969;Langenauer, Davis and Webster, 1974) and the use of aquatic plants (Clowes, 1959;Gifford, 1960a). It is sometimes possible to obtain quantitative results with intact plants with colchicine, but not with DNA precursors (Rolinson, 1975).…”

Section: Introductionmentioning

confidence: 99%

DEVELOPMENT OF THE SHOOT APEX IN ZEA MAYS

Clowes

1978

New Phytologist

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SUMMARYIntact embryos of Zea mays have been studied by stathmokinesis and DNA labelling to find rates of cell proliferation in the regions of the developing shoot apex, and these have been compared with rates for seedlings, whose apices have to be partially uncovered for this purpose. In young embryo shoots, cells divide faster than they do in seedhngs and rates at the summit do not differ greatly from those in the rest of the apex. The tunica, which contains about half the cells in the apex, contributes a decreasing fraction of the total cell production as the embryo ages. The results are discussed in relation to the maturation of the seed and the changes in the numbers of cells in the regions of the meristem.

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Analytical studies on the shoot apex of Helianthus annuus

Cited by 49 publications

References 13 publications

Cell-Type-Specific Expression of Plant Cytochrome cmRNA in Developing Flowers and Roots

Cell-Type-Specific Expression of Plant Cytochrome cmRNA in Developing Flowers and Roots

Developmental studies on leafy spurge (Euphorbia esula). Histochemical and autoradiographic studies of the adventitious shoot apices

DEVELOPMENT OF THE SHOOT APEX IN ZEA MAYS

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