Developmental potentialities of leaf primordia of Osmunda cinnamomea. IV. Expression-potential of undetermined primordia separated by a barrier membrane from undetermined or determined primordia

1969 ◽  
Vol 47 (1) ◽  
pp. 69-72 ◽  
Author(s):  
Charles Carroll Kuehnert
Keyword(s):  
Leaf Primordia ◽  
Leaf Primordium ◽  
Cell Contact ◽  
Millipore Filter ◽  
Control Center ◽  
Sterile Culture ◽  
Barrier Membrane ◽  
Expression Potential

Undetermined P3 leaf primordia of the fern Osmunda cinnamomea were excised and grown in sterile culture, as pairs, with P12 or P13 primordia, primordia already irreversibly determined as leaves. Undetermined P3 primordia of a pair (P3 with P3 or P3 with P12) separated by an impervious barrier membrane (mica sheets) exhibit a tendency to develop as shoots rather than leaves. When the barrier membrane was a Millipore Filter, P3's growing with other P3's also exhibited the tendency to develop as shoots. By contrast, undetermined P3 primordia of a pair (P3 with P13) separated by a Millipore Filter barrier membrane exhibit the tendency to develop as leaves. These results would suggest that cell-to-cell contact is not a necessary adjunct to transmission of a leafness morphogen, and they present still further evidence in favor of a hypothesis that determination of a leaf primordium as a leaf may be under the control of more than one control center, and that one such control center is associated with certain of the older leaf primordia of a sibling series.

scholarly journals Extended expression of MaKN1 contributes to the leaf morphology in aquatic forms of Myriophyllum aquaticum

Botany ◽  
2015 ◽  
Vol 93 (9) ◽  
pp. 611-621
Author(s):  
M.D. Shafiullah ◽  
Christian R. Lacroix
Keyword(s):  
Apical Meristem ◽  
Leaf Morphology ◽  
Expression Patterns ◽  
Homeobox Gene ◽  
Leaf Primordia ◽  
Leaf Primordium ◽  
Myriophyllum Aquaticum ◽  
Knox Gene ◽  
Leaf Morphogenesis

Myriophyllum aquaticum (Vell.) Verdc. is heterophyllous in nature with highly dissected simple leaves consisting of several lobes. KNOX (KNOTTED1-LIKE HOMEOBOX) genes are believed to have played an important role in the evolution of leaf diversity. Up-regulation of KNOX during leaf primordium initiation can lead to leaf dissection in plants with simple leaves and, if overexpressed, can produce ectopic meristems on leaves. A previous study on KNOX gene expression in the aerial form of this species showed that this gene is expressed in the shoot apical meristem (SAM), as well as in leaf primordia P0 to P8. Based on these results, it was hypothesized that the prolonged expression of the MaKN1 (Myriophyllum aquaticum Knotted1-like homeobox) gene beyond P8, might play an important role in the generation of more lobes, longer lobes, and hydathode formation in the aquatic leaves of M. aquaticum. The technique of in situ hybridization was carried out using a previously sequenced 300 bp fragment of MaKN1 to determine the expression patterns of this gene in the shoot of aquatic forms of the plant. Expression patterns of MaKN1 revealed that the SAM and leaf primordia of aquatic forms of M. aquaticum at levels P0 (youngest) to P4 were distributed throughout these structures. The level of expression of this MaKN1 gene progressively became more localized to lobes in older leaf primordia (levels P5 to P12). Previous studies of aerial forms of this plant showed MaKN1 expression until P8. Our results with aquatic forms show that the highly dissected leaf morphology in aquatic forms was the result of the prolonged expression of MaKN1 beyond P8. This resulted in the formation of elongated and slightly more numerous lobes, and hydathodes in aquatic forms. These findings support the view that KNOX genes are important developmental regulators of leaf morphogenesis and have played an important role in the evolution of leaf forms in the plant kingdom.

Phyllotaxis of the palm Euterpe oleracea Mart. at the level of the shoot apical meristem

Botany ◽  
2010 ◽  
Vol 88 (5) ◽  
pp. 528-536 ◽  
Author(s):  
Denis Barabé ◽  
Laura Bourque ◽  
Xiaofeng Yin ◽  
Christian Lacroix
Keyword(s):  
Shoot Apical Meristem ◽  
Fundamental Theorem ◽  
Apical Meristem ◽  
Leaf Primordia ◽  
Leaf Primordium ◽  
Divergence Angle ◽  
Euterpe Oleracea ◽  
The Mean ◽  
The Relationship ◽  
Euterpe Oleracea Mart

Previous studies on palm phyllotaxis deal mainly with the mature trunk. The goals of this study are (i) to determine the relationship between the number of parastichies, the divergence angle, and the plastochrone ratio at the level of the shoot apical meristem; (ii) to examine whether there are fluctuations in the divergence angle; (iii) to interpret the significance of phyllotactic parameters with respect to the mode of growth of the apex. The tubular base of the leaf primordium is more or less asymmetrical, and completely surrounds the shoot apical meristem. The phyllotactic system corresponds to a (2, 3) conspicuous parastichy pair. The mean divergence angle per apex varies between 126.9° ± 9.3° (mean ± SD) and 135. 8° ± 8.0°. Divergence angles for all apices fluctuate within a range of 115.89° to 157.33°. The mean plastochrone ratios between apices varies from 1.35 ± 0.18 to 1.58 ± 0.12. The plastochrone ratio at each plastochrone for all apices ranges from 1.09 to 2.00. There is no correlation between the angle of divergence and the plastochrone ratio. There is a fluctuation in the value of the divergence angle that falls within the range predicted by the fundamental theorem of phyllotaxis. The high value of the ratio of the diameter of leaf primordia over the diameter of the apex, and the long plastochrone might explain the lack of correlation between certain phyllotactic parameters.

scholarly journals Macrosight: A Novel Framework to Analyze the Shape and Movement of Interacting Macrophages Using Matlab®

2019 ◽  
Vol 5 (1) ◽  
pp. 17 ◽  
Author(s):  
José Solís-Lemus ◽  
Brian Stramer ◽  
Greg Slabaugh ◽  
Constantino Reyes-Aldasoro
Keyword(s):  
Cell Migration ◽  
Data Analysis ◽  
Statistical Significance ◽  
Cell Interactions ◽  
Cell Contact ◽  
Software Framework ◽  
Change Of Direction ◽  
Cell Structures ◽  
Before And After

This paper presents a novel software framework, called macrosight, which incorporates routines to detect, track, and analyze the shape and movement of objects, with special emphasis on macrophages. The key feature presented in macrosight consists of an algorithm to assess the changes of direction derived from cell–cell contact, where an interaction is assumed to occur. The main biological motivation is the determination of certain cell interactions influencing cell migration. Thus, the main objective of this work is to provide insights into the notion that interactions between cell structures cause a change in orientation. Macrosight analyzes the change of direction of cells before and after they come in contact with another cell. Interactions are determined when the cells overlap and form clumps of two or more cells. The framework integrates a segmentation technique capable of detecting overlapping cells and a tracking framework into a tool for the analysis of the trajectories of cells before and after they overlap. Preliminary results show promise into the analysis and the hypothesis proposed, and lays the groundwork for further developments. The extensive experimentation and data analysis show, with statistical significance, that under certain conditions, the movement changes before and after an interaction are different from movement in controlled cases.

scholarly journals Lunar Radiometric Measurement Based on Observing China Chang’E-3 Lander with VLBI—First Insight

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
SongTao Han ◽  
ZhongKai Zhang ◽  
Jing Sun ◽  
JianFeng Cao ◽  
Lue Chen ◽  
...  
Keyword(s):  
Lunar Surface ◽  
Current Status ◽  
Accuracy Analysis ◽  
Radiometric Measurement ◽  
Soft Landing ◽  
Control Center ◽  
Lunar Reconnaissance Orbiter ◽  
International Vlbi Service ◽  
Lunar Lander

China Chang’E-3 performed soft landing at the plains of Sinus Iridum on lunar surface on December 14th 2013 successfully; it opened a new window for observing lunar surface with radiometric tracking which many lunar scientific researchers always pursue for. Since July 2014, OCEL (Observing Chang’E-3 Lander with VLBI) project has been conducted jointly by IVS (International VLBI Service of Geodesy and Astrometry) and BACC (Beijing Aerospace Control Center), a global IVS R&D network augmented with two China Deep Space Stations configured for OCEL. This paper presents the current status and preliminary result of the OCEL and mainly focuses on determination of the lander position, which is about 7 meter in height and 14 meter in plane of lunar surface with respect to LRO (Lunar Reconnaissance Orbiter). Based on accuracy analysis, further optimized OCEL sessions will make use of this target-of-opportunity, the Chang’E-3 lunar lander, as long as it is working. With higher accurate radiometric observables, more prospective contribution to earth and lunar science is expected by combining with LLR.

The rotated-lamina syndrome. I. Ulmaceae

1993 ◽  
Vol 71 (2) ◽  
pp. 211-221 ◽  
Author(s):  
W. A. Charlton
Keyword(s):  
Leaf Blade ◽  
Early Stage ◽  
Leaf Primordia ◽  
Leaf Primordium ◽  
Foliage Leaf ◽  
Normal Orientation ◽  
Ulmus Glabra ◽  
Young Leaves ◽  
Final Orientation ◽  
Zelkova Serrata

In a number of plants, mostly woody, the components of the buds are arranged so that the laminae of the young leaves all face towards the same (upper) side of the bud, rather than towards the bud apex; in axillary buds they usually face towards the parent axis. This situation has been known for many years. For convenience, the general case is here called the rotated-lamina syndrome. There have been very few developmental investigations of how the laminae attain their unusual orientation, and these have come to different conclusions about cases in the Ulmaceae. This paper reports a detailed investigation of the syndrome in Ulmus glabra and Zelkova serrata, with comparative observations on other Ulmaceae, including cases in Celtis that do not exhibit the syndrome. The syndrome arises by different means in Ulmus and Zelkova. In Ulmus the leaf primordium is asymmetrical from the outset, the leaf blade region is obliquely dorsiventral from an early stage, and further asymmetrical growth of the leaf buttress rotates the whole leaf blade region into its final orientation as it develops. Individual shoots show heteroblastic development in progressing from bud scale to foliage leaf initiation, in increasing accentuation of the rotated-lamina syndrome, and in an increasing degree of dorsiventrality. In Zelkova, as previously described, the leaf blade region appears first as a radially symmetrical upgrowth, and it acquires dorsiventral symmetry directly in the rotated position. In Celtis spp. the lamina arises in a quite normal orientation, but reorients as it emerges from the bud. The leaf primordia of all species studied show asymmetry in other aspects, particularly in respect of stipule development, and these seem to be general features of the organisation of dorsiventral shoots. Key words: Ulmus, Zelkova, Celtis, leaf, development, dorsiventrality, lamina rotation.

scholarly journals Determination of polyadenylate-rich ribonucleic acid in the nucleus and in the cytoplasm of plasmacytoma cells

1975 ◽  
Vol 149 (3) ◽  
pp. 669-674 ◽  
Author(s):  
K A Abraham ◽  
T S Eikhom
Keyword(s):  
Ph Dependence ◽  
Specific Radioactivity ◽  
Nuclear Fraction ◽  
High Concentration ◽  
Millipore Filter ◽  
Filter Technique ◽  
Short And Long Term ◽  
Millipore Filters

A number of parameters affecting the adsorption of rRNA and poly(A)-containing RNA to Millipore filters were investigated separately. Binding of both types of RNA to the filter was dependent on the concentration of RNA, pH and Mg2+ concentration of the reaction mixture. Both types of RNA bound to the filter optimally at slightly acid pH values. The binding of poly(A)-containing RNA to the filter exhibited a broad pH-dependence compared with that of rRNA. The ratio of poly(A)-rich RNA/rRNA retained by the filter was maximal between pH7 and 8. The presence of 1 mM-EDTA or a high concentration of NaCl (over 0.5M) decreased the affinity of RNA for the filter. The amount of poly(A)-containing RNA in the nucleus and in the cytoplasm of a plasmacytoma cell line (MPC-11) labelled with [32P]Pi was determined by the Millipore-filter technique under conditions that minimized contamination by rRNA. These data were compared with the estimations made by oligo(dT)-cellulose chromatography. The results obtained by these two methods were in good agreement for RNA labelled for short periods (up to 2h). In long labelling and pulse-chase experiments, however, contamination of the filter by rRNA of increasing specific radioactivity in the cytoplasm gave an erroneous value for poly(A)-containing RNA by the Millipore-filter technique. Determinations made on the nuclear fraction by these two methods did not show significant variation in short- and long-term labelling experiments.

Accelerating effect of hydrocortisone on the keratinization of chick embryonic skin growing in a chemically defined medium

Development ◽  
1971 ◽  
Vol 25 (3) ◽  
pp. 365-376
Author(s):  
Masanobu Sugimoto ◽  
Hiroyoshi Endo
Keyword(s):  
Culture Method ◽  
Defined Medium ◽  
Chemically Defined Medium ◽  
In Ovo ◽  
Millipore Filter ◽  
Embryonic Skin ◽  
Minimal Concentration ◽  
Chick Embryonic Skin

In an attempt to examine histologically, chemically and biochemically the effect of hydrocortisone in a minimal concentration on keratinization of 13-day chick embryonic shank skin, a simple replicate culture method (‘Millipore’ filter-roller-tube method) was devised to cultivate rather large pieces of the skin in a chemically defined medium, BGJb supplemented with ascorbate. Hydrocortisone added in a minimal concentration of 0·001 μg/ml produced a heavily cornified eosinophilic layer over the epidermis after 4 days' cultivation, whereas in the absence of the steroid no sign of cornification could be found during culture. Determination of total protein and analysis of amino acid composition of whole protein of the epidermis indicated that hydrocortisone accelerated epidermal cornification as compared with in ovo development. Pregnenolone and progesterone showed no effect on the in vitro keratinization of the epidermis and deoxycorticosterone gave a slight effect: thus the cornification-accelerating effect of hydrocortisone seems to be attributable to its glucocorticoid activity.

The initial protrusion of a leaf primordium can form without concurrent periclinal cell divisions

1971 ◽  
Vol 49 (9) ◽  
pp. 1601-1603 ◽  
Author(s):  
Donald E. Foard
Keyword(s):  
Gamma Rays ◽  
Shoot Apex ◽  
Cell Layer ◽  
Fold Increase ◽  
Leaf Primordia ◽  
Leaf Primordium ◽  
Initial Number ◽  
Wheat Grains ◽  
Cell Divisions ◽  
Number Of Cells

The view that periclinal cell divisions cause the initial protrusion of a leaf primordium may be tested by using ionizing radiation to prevent cell divisions without preventing growth. After receiving 800 krad of gamma rays, wheat grains containing embryos with three leaf primordia produce seedlings in which a fourth protrusion of the shoot apex forms unaccompanied by cell divisions. This protrusion without periclinal divisions occurs in the same phyllotactic position as that of the fourth leaf primordium in which periclinal divisions occur. In addition to proper phyllotactic position, the protrusion without cell divisions is formed by the outermost cell layer, as is the initial protrusion of a typical leaf primordium of wheat; moreover, the initial number of cells involved is the same in both kinds of protrusions. Therefore the fourth protrusion in seedlings from irradiated grain is interpreted as the initial protrusion of a leaf primordium that formed without periclinal cell divisions. Measured along the axis of greatest extension, the protrusions without cell divisions represent about a four- to eight-fold increase over the anticlinal dimension of the surface-cell layer in the embryo. These protrusions do not develop further. The absence of cell divisions limits the extent of primordial growth, but does not prevent its inception. Periclinal cell divisions do not cause the initial protrusion of a leaf primordium.

DEVELOPMENTAL POTENTIALITIES OF LEAF PRIMORDIA OF OSMUNDA CINNAMOMEA: THE INFLUENCE OF DETERMINED LEAF PRIMORDIA ON UNDETERMINED LEAF PRIMORDIA

1967 ◽  
Vol 45 (11) ◽  
pp. 2109-2113 ◽  
Author(s):  
Charles Carroll Kuehnert
Keyword(s):  
Active Site ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Alternative Hypothesis ◽  
Leaf Primordia ◽  
Sterile Culture ◽  
Indirect Control

In the fern Osmunda cinnamomea, leaf primorida may be excised and grown in sterile culture before or subsequent to their irreversible determination as leaves. It has been demonstrated that P3 primordia (third-oldest primordia) are not irreversibly determined as leaves at the time of excision for they exhibit a tendency to develop as shoots rather than leaves when cultured aseptically. When grown singly they become shoots 75.0% of the time; when grown in physiological contact as paired units they exhibit a tendency to become shoots at approximately the same level. The hypothesis that the active site of leaf determination is through the direct or indirect control of the shoot apical meristem is questioned and an alternative hypothesis is proposed which suggests that a morphogenetic factor is formed in older primordia which will diffuse to younger primordia to influence younger primordia to develop as leaves rather than shoots. The latter hypothesis is supported by experiments in which P3 primordia grown in physiological contact (as pairs) with P10 or P12 primordia produce more than twice as many leaves as unpaired or paired P3 primordia.

scholarly journals A new mathematical model of phyllotaxis to solve the genuine puzzle spiromonostichy

2021 ◽  
Author(s):  
Takaaki Yonekura ◽  
Munetaka Sugiyama
Keyword(s):  
Mathematical Model ◽  
Mathematical Models ◽  
Computer Simulations ◽  
Inductive Effect ◽  
Inhibitory Effect ◽  
Leaf Primordia ◽  
Leaf Primordium ◽  
Spiral Pattern ◽  
The Mathematical Model ◽  
Mathematical Model Analysis

The view is widely accepted that the inhibitory effect of existing leaf primordia on new primordium formation determines phyllotactic patterning. Previous studies have shown that mathematical models based on such inhibitory effect can generate most of phyllotactic patterns. However, a few types of phyllotaxis still remain unaddressed. A notable example is costoid phyllotaxis showing spiromonostichy, which is characterized by a steep spiral with a small divergence angle and is unique to Costaceae plants. Costoid phyllotaxis has been called a "genuine puzzle" because it seems to disagree with the inhibitory effect-based mechanism. In an attempt to produce a steep spiral pattern, we developed a new mathematical model assuming that each leaf primordium emits not only the inhibitory effect but also some inductive effect. Computer simulations with the new model successfully generated a steep spiral pattern when these two effects met a certain relationship. The obtained steep spiral matched the real costoid phyllotaxis observed with Costus megalobractea. We also found by the mathematical model analysis that the early phyllotactic transition in the seedlings of this plant can be explained by the SAM enlargement.

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