scholarly journals Diversity of phyllotaxis in land plants in reference to the shoot apical meristem structure

2016 ◽  
Vol 85 (4) ◽  
Author(s):  
Edyta M. Gola ◽  
Alicja Banasiak
Keyword(s):  
Pattern Formation ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Land Plants ◽  
Phyllotactic Pattern ◽  
Lateral Organs ◽  
Spatio Temporal

Regularity and periodicity in the arrangements of organs in all groups of land plants raise questions about the mechanisms underlying phyllotactic pattern formation. The initiation of the lateral organs (leaves, flowers, etc.), and thus, their spatio-temporal positioning, occurs in the shoot apical meristem (SAM) and is related to the structure and organogenic activity of the meristem. In this review, we present some aspects of the diversity and stability of phyllotactic patterns in the major lineages of land plants, from bryophytes to angiosperms, in which SAM structures differ significantly. In addition, we discuss some of the possible mechanisms involved in the formation of the recurring arrangement of the lateral organs.

scholarly journals Feedback from Lateral Organs Controls Shoot Apical Meristem Growth by Modulating Auxin Transport

2018 ◽  
Vol 44 (2) ◽  
pp. 204-216.e6 ◽  
Author(s):  
Bihai Shi ◽  
Xiaolu Guo ◽  
Ying Wang ◽  
Yuanyuan Xiong ◽  
Jin Wang ◽  
...  
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Auxin Transport ◽  
Lateral Organs

Interplay between the shoot apical meristem and lateral organs

aBIOTECH ◽  
2020 ◽  
Vol 1 (3) ◽  
pp. 178-184
Author(s):  
Chunmei Guan ◽  
Yuling Jiao
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Lateral Organs

scholarly journals Does Shoot Apical Meristem Function as the Germline in Safeguarding Against Excess of Mutations?

2021 ◽  
Vol 12 ◽  
Author(s):  
Agata Burian
Keyword(s):  
Cell Fate ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Cell Lineage ◽  
Temporal Distribution ◽  
Tissue Level ◽  
Protective Mechanisms ◽  
Genetic Continuity ◽  
Spatio Temporal ◽  
Living Organisms

A genetic continuity of living organisms relies on the germline which is a specialized cell lineage producing gametes. Essential in the germline functioning is the protection of genetic information that is subjected to spontaneous mutations. Due to indeterminate growth, late specification of the germline, and unique longevity, plants are expected to accumulate somatic mutations during their lifetime that leads to decrease in individual and population fitness. However, protective mechanisms, similar to those in animals, exist in plant shoot apical meristem (SAM) allowing plants to reduce the accumulation and transmission of mutations. This review describes cellular- and tissue-level mechanisms related to spatio-temporal distribution of cell divisions, organization of stem cell lineages, and cell fate specification to argue that the SAM functions analogous to animal germline.

scholarly journals Expression of maize KNOTTED1 related homeobox genes in the shoot apical meristem predicts patterns of morphogenesis in the vegetative shoot

Development ◽  
1994 ◽  
Vol 120 (2) ◽  
pp. 405-413 ◽  
Author(s):  
D. Jackson ◽  
B. Veit ◽  
S. Hake
Keyword(s):  
Shoot Apical Meristem ◽  
Leaf Development ◽  
Apical Meristem ◽  
Expression Patterns ◽  
Homeobox Genes ◽  
Homeobox Gene ◽  
Vegetative Shoot ◽  
Lateral Organs ◽  
Floral Meristems ◽  
Shoot Meristems

In this paper we describe the expression patterns of a family of homeobox genes in maize and their relationship to organogenic domains in the vegetative shoot apical meristem. These genes are related by sequence to KNOTTED1, a gene characterized by dominant neomorphic mutations which perturb specific aspects of maize leaf development. Four members of this gene family are expressed in shoot meristems and the developing stem, but not in determinate lateral organs such as leaves or floral organs. The genes show distinct expression patterns in the vegetative shoot apical meristem that together predict the site of leaf initiation and the basal limit of the vegetative ‘phytomer’ or segmentation unit of the shoot. These genes are also expressed in the inflorescence and floral meristems, where their patterns of expression are more similar, and they are not expressed in root apical meristems. These findings are discussed in relation to other studies of shoot apical meristem organization as well as possible commonality of homeobox gene function in the animal and plant kingdoms.

Shoot apical meristem and cotyledon formation during Arabidopsis embryogenesis: interaction among the CUP-SHAPED COTYLEDON and SHOOT MERISTEMLESS genes

Development ◽  
1999 ◽  
Vol 126 (8) ◽  
pp. 1563-1570 ◽  
Author(s):  
M. Aida ◽  
T. Ishida ◽  
M. Tasaka
Keyword(s):  
Pattern Formation ◽  
Mrna Expression ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Higher Plants ◽  
Expression Patterns ◽  
Genetic Interactions ◽  
Apical Region ◽  
Arabidopsis Embryogenesis ◽  
Shoot Meristemless

The shoot apical meristem and cotyledons of higher plants are established during embryogenesis in the apex. Redundant CUP-SHAPED COTYLEDON 1 (CUC1) and CUC2 as well as SHOOT MERISTEMLESS (STM) of Arabidopsis are required for shoot apical meristem formation and cotyledon separation. To elucidate how the apical region of the embryo is established, we investigated genetic interactions among CUC1, CUC2 and STM, as well as the expression patterns of CUC2 and STM mRNA. Expression of these genes marked the incipient shoot apical meristem as well as the boundaries of cotyledon primordia, consistent with their roles for shoot apical meristem formation and cotyledon separation. Genetic and expression analyses indicate that CUC1 and CUC2 are redundantly required for expression of STM to form the shoot apical meristem, and that STM is required for proper spatial expression of CUC2 to separate cotyledons. A model for pattern formation in the apical region of the Arabidopsis embryo is presented.

scholarly journals Signals flowing from mature tissues to shoot apical meristem affect phyllotaxis in coniferous shoot.

2011 ◽  
Vol 75 (2) ◽  
pp. 113-121 ◽  
Author(s):  
Beata Zagórska-Marek ◽  
Alicja Banasiak
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Initiation Site ◽  
Xylem Differentiation ◽  
Spiral Pattern ◽  
Vegetative Shoot ◽  
Phyllotactic Pattern ◽  
Growth Increments ◽  
Organ Identity ◽  
Selection Of

Axial homodromy in growing shoots of perennial plants with spiral phyllotaxis is the case when the chirality of phyllotactic pattern does not change in consecutive growth increments of the same axis. In conifers such as <em>Picea</em> or<em> Abies</em> this rule is strictly observed, except for the rare cases of discontinuous phyllotactic transitions. In <em>Torreya</em>, however, the chirality changes, at random, every year. The pattern of primordia packing, executed by vegetative shoot apical meristem (SAM), depends in <em>Torreya</em> on their identity. The primordia of bud scales are initiated in the decussate and those of needles in bijugate spiral pattern. The decussate, achiral i.e. neutral pattern always precedes the formation of new spiral pattern and thus facilitates random selection of its chiral configuration. Periodic change in organ identity cannot itself be responsible for the special behavior of <em>Torreya</em>, because in other conifers it also exists. There is, however, one important difference: in Torreya, when the initiation of bud scales begins at SAM, the distance between differentiated protoxylem and the initiation site gradually increases, while in other conifers it remains constant and small. In <em>Torreya</em>, at this phase of development, the rate of xylem differentiation and the rate of organogenesis become uncoupled. Closer anatomical examination shows that the decussate pattern in a bud scale zone develops slowly suggesting gradual decrease of the putative signal flowing acropetally from differentiated protoxylem, responsible for positioning of primordia. We hypothesize that in the absence of this signal SAM starts acting autonomously, distributing primordia according to their identity only. A constant presence of the signal in other conifers assures the continuation of the same phyllotactic pattern throughout the period of bud scale formation, despite the change in organ identity.

Phyllotactic transitions in seedlings: the case of Thuja occidentalis

Botany ◽  
2011 ◽  
Vol 89 (6) ◽  
pp. 387-396 ◽  
Author(s):  
Xiaofeng Yin ◽  
Christian Lacroix ◽  
Denis Barabé
Keyword(s):  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Divergence Angle ◽  
Apical Angle ◽  
Thuja Occidentalis ◽  
Phyllotactic Pattern ◽  
Insertion Angle ◽  
Eastern White Cedar ◽  
Leaf Insertion ◽  
Angle Parameter

The main goal of this study was to examine different phyllotactic patterns and pattern transitions in seedlings of eastern white cedar ( Thuja occidentalis L.). Four phyllotactic patterns were observed on the main stem of T. occidentalis: tetracussate, tricussate, (3, 5) spiral, and decussate. Only one phyllotactic pattern was observed on the side branches of T. occidentalis: decussate. Four types of phyllotactic pattern transition were observed: tetracussate to decussate, tetracussate to tricussate, tricussate to (3, 5) spiral, and (3, 5) spiral to decussate. For each phyllotactic pattern, the following phyllotactic parameters were examined using histological sections: divergence angle, plastochrone ratio, leaf insertion angle, parameter Г, and apical angle of the shoot apical meristem (SAM). Even though they varied widely, the phyllotactic parameters measured in T. occidentalis seem to fall within ranges observed in other plants for specific phyllotactic patterns. The results indicate that it is not possible to discriminate between the four different phyllotactic patterns observed on T. occidentalis by using the plastochrone ratio, leaf insertion angle, parameter Г, or apical angle of the SAM. In contrast to continuous transitions, where there is a good correlation between phyllotactic parameters, there was no correlation between the phyllotactic pattern (characterized by a given divergence angle) and other phyllotactic parameters in the discontinuous transitions observed in T. occidentalis.

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