Limits...
Influence of clavata3-2 mutation on early flower development in Arabidopsis thaliana: quantitative analysis of changing geometry.

Szczesny T, Routier-Kierzkowska AL, Kwiatkowska D - J. Exp. Bot. (2008)

Bottom Line: In particular, the shape of the adaxial primordium boundary varies and seems to be related to the shape of the space available for the given primordium formation, suggesting that physical constraints play a significant role in primordium shape determination.Moreover, there is only one tunica layer in both the meristem and in the primordium until it becomes a bulge that is distinctly separated from the meristem.Starting from this stage, the anticlinal divisions predominate in subprotodermal cells, suggesting that the distribution of periclinal and anticlinal cell divisions in the early development of the flower primordium is not directly affected by the clv3-2 mutation.

View Article: PubMed Central - PubMed

Affiliation: Institute of Plant Biology, University of Wrocław, Kanonia 6/8, 50-328 Wrocław, Poland.

ABSTRACT
Early development of the flower primordium has been studied in Arabidopsis thaliana clavata3-2 (clv3-2) plants with the aid of sequential in vivo replicas and longitudinal microtome sections. Sequential replicas show that, although there is no regular phyllotaxis in the clv3-2 inflorescence shoot apex, the sites of new primordium formation are, to a large extent, predictable. The primordium always appears in a wedge-like region of the meristem periphery flanked by two older primordia. In general, stages of primordium development in clv3-2 are similar to the wild type, but quantitative geometry analysis shows that the clv3-2 primordium shape is affected even before the CLAVATA/WUSCHEL regulatory network would start to operate in the wild-type primordium. The shape of the youngest primordium in the mutant is more variable than in the wild type. In particular, the shape of the adaxial primordium boundary varies and seems to be related to the shape of the space available for the given primordium formation, suggesting that physical constraints play a significant role in primordium shape determination. The role of physical constraints is also manifested in that the shape of the primordium in the later stages, as well as the number and position of sepals, are adjusted to the available space. Longitudinal sections of clv3-2 apices show that the shape of surface cells of the meristem and young primordium is different from the wild type. Moreover, there is only one tunica layer in both the meristem and in the primordium until it becomes a bulge that is distinctly separated from the meristem. Starting from this stage, the anticlinal divisions predominate in subprotodermal cells, suggesting that the distribution of periclinal and anticlinal cell divisions in the early development of the flower primordium is not directly affected by the clv3-2 mutation.

Show MeSH
Central longitudinal sections of three clv3-2 apices. Inflorescence SAM sectioned in the median plane and the earliest stage flower primordium (P) are labelled. The arrow points to a smaller, additional meristem, appearing due to fasciation, that most likely is not in a median section (A, C). Note the characteristic shapes of SAM L1 cells as compared with L1 cells of the bulge stage flower primordium (asterisks). Insets show the overall shape of the apices. Bars=50 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC2651453&req=5

fig13: Central longitudinal sections of three clv3-2 apices. Inflorescence SAM sectioned in the median plane and the earliest stage flower primordium (P) are labelled. The arrow points to a smaller, additional meristem, appearing due to fasciation, that most likely is not in a median section (A, C). Note the characteristic shapes of SAM L1 cells as compared with L1 cells of the bulge stage flower primordium (asterisks). Insets show the overall shape of the apices. Bars=50 μm.

Mentions: The shape of clv3-2 inflorescence SAM is complex and very variable (Figs 1, 13). Thus it is difficult to obtain a precise median longitudinal section of the meristem. Since meristems are often fasciated, some of the sections probably show more than one meristem, not necessarily both in their median section (as in Figs 13A or C, where quite possibly two meristems are present: the bigger meristem in the median section, and the smaller one, indicated by an arrow, is probably not sectioned in the median plane).


Influence of clavata3-2 mutation on early flower development in Arabidopsis thaliana: quantitative analysis of changing geometry.

Szczesny T, Routier-Kierzkowska AL, Kwiatkowska D - J. Exp. Bot. (2008)

Central longitudinal sections of three clv3-2 apices. Inflorescence SAM sectioned in the median plane and the earliest stage flower primordium (P) are labelled. The arrow points to a smaller, additional meristem, appearing due to fasciation, that most likely is not in a median section (A, C). Note the characteristic shapes of SAM L1 cells as compared with L1 cells of the bulge stage flower primordium (asterisks). Insets show the overall shape of the apices. Bars=50 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2651453&req=5

fig13: Central longitudinal sections of three clv3-2 apices. Inflorescence SAM sectioned in the median plane and the earliest stage flower primordium (P) are labelled. The arrow points to a smaller, additional meristem, appearing due to fasciation, that most likely is not in a median section (A, C). Note the characteristic shapes of SAM L1 cells as compared with L1 cells of the bulge stage flower primordium (asterisks). Insets show the overall shape of the apices. Bars=50 μm.
Mentions: The shape of clv3-2 inflorescence SAM is complex and very variable (Figs 1, 13). Thus it is difficult to obtain a precise median longitudinal section of the meristem. Since meristems are often fasciated, some of the sections probably show more than one meristem, not necessarily both in their median section (as in Figs 13A or C, where quite possibly two meristems are present: the bigger meristem in the median section, and the smaller one, indicated by an arrow, is probably not sectioned in the median plane).

Bottom Line: In particular, the shape of the adaxial primordium boundary varies and seems to be related to the shape of the space available for the given primordium formation, suggesting that physical constraints play a significant role in primordium shape determination.Moreover, there is only one tunica layer in both the meristem and in the primordium until it becomes a bulge that is distinctly separated from the meristem.Starting from this stage, the anticlinal divisions predominate in subprotodermal cells, suggesting that the distribution of periclinal and anticlinal cell divisions in the early development of the flower primordium is not directly affected by the clv3-2 mutation.

View Article: PubMed Central - PubMed

Affiliation: Institute of Plant Biology, University of Wrocław, Kanonia 6/8, 50-328 Wrocław, Poland.

ABSTRACT
Early development of the flower primordium has been studied in Arabidopsis thaliana clavata3-2 (clv3-2) plants with the aid of sequential in vivo replicas and longitudinal microtome sections. Sequential replicas show that, although there is no regular phyllotaxis in the clv3-2 inflorescence shoot apex, the sites of new primordium formation are, to a large extent, predictable. The primordium always appears in a wedge-like region of the meristem periphery flanked by two older primordia. In general, stages of primordium development in clv3-2 are similar to the wild type, but quantitative geometry analysis shows that the clv3-2 primordium shape is affected even before the CLAVATA/WUSCHEL regulatory network would start to operate in the wild-type primordium. The shape of the youngest primordium in the mutant is more variable than in the wild type. In particular, the shape of the adaxial primordium boundary varies and seems to be related to the shape of the space available for the given primordium formation, suggesting that physical constraints play a significant role in primordium shape determination. The role of physical constraints is also manifested in that the shape of the primordium in the later stages, as well as the number and position of sepals, are adjusted to the available space. Longitudinal sections of clv3-2 apices show that the shape of surface cells of the meristem and young primordium is different from the wild type. Moreover, there is only one tunica layer in both the meristem and in the primordium until it becomes a bulge that is distinctly separated from the meristem. Starting from this stage, the anticlinal divisions predominate in subprotodermal cells, suggesting that the distribution of periclinal and anticlinal cell divisions in the early development of the flower primordium is not directly affected by the clv3-2 mutation.

Show MeSH