Using a mathematical model to evaluate the trophic and non-trophic determinants of axis development in grapevine

2009 ◽  
Vol 36 (2) ◽  
pp. 156 ◽  
Author(s):  
Benoît Pallas ◽  
Angélique Christophe ◽  
Paul-Henry Cournède ◽  
Jérémie Lecoeur
Keyword(s):  
Mathematical Model ◽  
Shoot Development ◽  
High Variability ◽  
Vitis Vinifera L ◽  
Organ Mass ◽  
Secondary Axis ◽  
Repetitive Structure ◽  
Primary Axis ◽  
Branching System ◽  
Trophic Competition

The grapevine (Vitis vinifera L.) shoot is a complex modular branching system, with one primary axis and many secondary axes organised into a repetitive structure of three successive phytomers (P0-P1-P2). P1-P2 phytomers bear one tendril or cluster, whereas P0 phytomers bear no tendrils or clusters. Axis development displays a high variability, due, partly, to trophic competition. The aim of this study was to estimate changes in trophic competition within the shoot, and to relate plasticity in axis development to changes in trophic competition. ‘Grenache N.’ and ‘Syrah’ cultivars were grown with two contrasting levels of cluster load. Organogenesis and organ mass were measured during shoot development. Changes in trophic competition were estimated, using the solver functions of the GreenLab model. Internodes and clusters were strong sinks. They affected the shoot development to the same extent, but the internodes showed an earlier effect. The cessation of development of the secondary axis was affected by trophic competition, but the primary axis continued to develop, regardless of trophic competition. Secondary axes differed in sensitivity to trophic competition as a function of two criteria: their type and their size. The most highly developed axes were less affected than the smaller axes, and secondary axes arising from a P0 phytomer were also less affected than secondary axes arising from a P1 or P2 phytomer.

Influence of intra-shoot trophic competition on shoot development in two grapevine cultivars (Vitis vinifera)

2008 ◽  
Vol 134 (1) ◽  
pp. 49-63 ◽  
Author(s):  
Benoît Pallas ◽  
Gaëtan Louarn ◽  
Angélique Christophe ◽  
Eric Lebon ◽  
Jérémie Lecoeur
Keyword(s):  
Vitis Vinifera ◽  
Shoot Development ◽  
Trophic Competition

Nitrogen supply controls vegetative growth, biomass and nitrogen allocation for grapevine (cv. Shiraz) grown in pots

2015 ◽  
Vol 42 (1) ◽  
pp. 105 ◽  
Author(s):  
Aurélie Metay ◽  
Jessica Magnier ◽  
Nicolas Guilpart ◽  
Angélique Christophe
Keyword(s):  
Vegetative Growth ◽  
Limiting Factor ◽  
Dependent Manner ◽  
Leaf Emergence ◽  
N Supply ◽  
Secondary Axis ◽  
Axis Elongation ◽  
Primary Axis ◽  
N Deficiency ◽  
Area Expansion

Maintaining grapevine productivity with limited inputs is crucial in Mediterranean areas. Apart from water, nitrogen (N) is also an important limiting factor in grape growing. The effects of N deficiency on grapevine growth were investigated in this study. Two-year-old Vitis vinifera L.cv. Shiraz plants grafted on 110 R were grown in pots placed outside and exposed to various N supplies (0, 0.6, 1.2, 2.4 and 12 g plant–1) under well-watered conditions. At veraison, plants were harvested and organs separately dried, weighed and analysed for N. During plant growth, the length of the primary and secondary axes and the number of leaves on them were recorded. The N content of leaves was also analysed at three phenological stages (flowering, bunch closure and veraison). All growth processes were inhibited by N deficiency in an intensity-dependent manner. Quantitative relationships with N supply were established. Vegetative growth responded negatively to N stress when comparing control N supply with no N supply: primary axis elongation (–61%), leaf emergence on the primary axis (–47%), leaf emergence on the secondary axis (–94%) and lamina area expansion (–45%). Significant differences on the plant N status were observed from flowering onwards which might be useful for managing fertilisation.

scholarly journals Inflorescence and Flower Development of the `Hass' Avocado (Persea americana Mill.) during “On” and “Off” Crop Years

1998 ◽  
Vol 123 (4) ◽  
pp. 537-544 ◽  
Author(s):  
Samuel Salazar-García ◽  
Elizabeth M. Lord ◽  
Carol J. Lovatt
Keyword(s):  
Flower Development ◽  
Persea Americana ◽  
High Yield ◽  
Reproductive Condition ◽  
Inflorescence Development ◽  
Apical Buds ◽  
Secondary Axis ◽  
Primary Axis ◽  
Hass Avocado ◽  
Flowering Process

Inflorescence and flower development of the `Hass' avocado (Persea americana Mill.) were investigated at the macro- and microscopic level with three objectives: 1) to determine the time of transition from vegetative to reproductive growth; 2) to develop a visual scale correlating external inflorescence and flower development with the time and pattern of organogenesis; and 3) to quantify the effect of high (“on”) and low (“off”) yields on the flowering process. Apical buds (or expanding inflorescences) borne on summer shoots were collected weekly from July to August during an “on” and “off” crop year. Collected samples were externally described and microscopically analyzed. The transition from vegetative to reproductive condition probably occurred from the end of July through August (end of shoot expansion). During this transition the primary axis meristem changed shape from convex to flat to convex. These events were followed by the initiation of additional bracts and their associated secondary axis inflorescence meristems. A period of dormancy was not a prerequisite for inflorescence development. Continued production of secondary axis inflorescence meristems was observed from August to October, followed by anthesis seven months later. In all, eleven visual stages of bud development were distinguished and correlated with organogenesis to create a scale that can be used to predict specific stages of inflorescence and flower development. Inflorescence development was correlated with minimum temperature ≤15 °C, whereas yield had little effect on the timing of developmental events of individual inflorescence buds. However, the high yield of the “on” year reduced inflorescence number and increased the number of vegetative shoots. No determinate inflorescences were produced during the “on” year. For the “off” year, 3% and 42% of shoots produced determinate and indeterminate inflorescences, respectively.

Acidity of and the concentrations of major and minor metals in the surface waters of bryophyte assemblages from 20 North American bogs and fens

2000 ◽  
Vol 78 (6) ◽  
pp. 718-727 ◽  
Author(s):  
Steven F Mullen ◽  
Jan A Janssens ◽  
Eville Gorham
Keyword(s):  
New York ◽  
Surface Water ◽  
Species Diversity ◽  
Surface Waters ◽  
Chemical Properties ◽  
Elemental Abundance ◽  
Secondary Axis ◽  
Alkaline Earths ◽  
Primary Axis ◽  
Components Analysis

One hundred and thirty-five samples of surface water, associated with bryophyte plots distributed across 20 wetlands in Newfoundland, Nova Scotia, Ontario, Alaska, Maine, Minnesota, and New York, were analyzed for pH and 11 elements, several of them seldom measured in wetlands. The overall order of elemental abundance was the following: Ca, Si, Na, Mg, Fe, K, Al, Mn, Sr, Ba, and Ti. Principal-components analysis of the pH and elemental chemistries of the water samples revealed seven subcategories that could be recognized as belonging to maritime and continental ombrotrophic bogs and poor, rich, and calcareous rich fens. The primary axis related to pH and the concentrations of alkaline earths, as well as to Si. The secondary axis segregated an unusual group of Alaskan fens; it was related mainly to Fe and Mn, and to a lesser degree Al and K. The tertiary axis separated maritime from continental bogs and was related chiefly to Na. The distribution of bryophyte species, most of them widespread in bogs and fens elsewhere, was most clearly related to pH and Ca concentration. As expected, many species exhibited narrow ranges of these chemical properties, whereas many others were widely distributed.Key words: mosses, peatlands, species diversity, water chemistry.

Autonomous differentiation of dorsal axial structures from an animal cap cleavage stage blastomere in Xenopus

Development ◽  
1991 ◽  
Vol 112 (4) ◽  
pp. 1103-1114 ◽  
Author(s):  
B.C. Gallagher ◽  
A.M. Hainski ◽  
S.A. Moody
Keyword(s):  
Original Position ◽  
Cleavage Stage ◽  
Cell Stage ◽  
Dorsal Midline ◽  
Developmental Program ◽  
Opposite Pole ◽  
Secondary Axis ◽  
Dorsal Axis ◽  
Exogenous Growth ◽  
Primary Axis

Dorsal or ventral blastomeres of the 16- and 32-cell stage animal hemisphere were labeled with a lineage dye and transplanted into the position of a ventral, vegetal midline blastomere. The donor blastomeres normally give rise to substantial amounts of head structures and central nervous system, whereas the blastomere which they replaced normally gives rise to trunk mesoderm and endoderm. The clones derived from the transplanted ventral blastomeres were found in tissues appropriate for their new position, whereas those derived from the transplanted dorsal blastomeres were found in tissues appropriate for their original position. The transplanted dorsal clones usually migrated into the host's primary axis (D1.1, 92%; D1.1.1, 69%; D1.1.2, 100%), and in many cases they also induced and populated a secondary axis (D1.1, 43%; D1.1.1, 67%; D1.1.2, 63%). Bilateral deletion of the dorsal blastomeres resulted in partial deficits of dorsal axial structures in the majority of cases, whereas deletions of ventral midline blastomeres did not. When the dorsal blastomeres were cultured as explants they elongated. Notochord and cement glands frequently differentiated in these explants. These studies show that the progeny of the dorsal, midline, animal blastomeres: (1) follow their normal lineage program to populate dorsal axial structures after the blastomere is transplanted to the opposite pole of the embryo; (2) induce and contribute to a secondary axis from their transplanted position in many embryos; (3) are important for the normal formation of the entire length of the dorsal axis; and (4) autonomously differentiate in the absence of exogenous growth factor signals. These data indicate that by the 16-cell stage, these blastomeres have received instructions regarding their fate, and they are intrinsically capable of carrying out some of their developmental program.

scholarly journals Inflorescence Development of the `Hass' Avocado: Commitment to Flowering

1999 ◽  
Vol 124 (5) ◽  
pp. 478-482 ◽  
Author(s):  
Samuel Salazar-García ◽  
Elizabeth M. Lord ◽  
Carol J. Lovatt
Keyword(s):  
Low Temperature ◽  
Developmental Stage ◽  
Persea Americana ◽  
Inflorescence Development ◽  
Apical Buds ◽  
Secondary Axis ◽  
Primary Axis ◽  
Hass Avocado ◽  
Old Trees

The developmental stage at which the shoot primary axis meristem (PAM) of the `Hass' avocado (Persea americana Mill.) is committed to flowering was determined. Three-year-old trees were subjected to low-temperature (LT) treatments at 10/7 °C day/night with a 10-h photoperiod for 1 to 4 weeks followed by 25/20 °C day/night at the same photoperiod. Before LT treatment, apical buds of mature vegetative shoots consisted of a convex PAM with two lateral secondary axis inflorescence meristems lacking apical bracts each associated with an inflorescence bract. Apical buds did not change anatomically during LT treatment. However, the 3- and 4-week LT treatments resulted in inflorescences at 17% and 83% of apical buds, respectively. Trees receiving 2 weeks or less LT, including controls maintained at 25/20 °C, produced only vegetative shoots. Apical buds of 2-year-old trees receiving 3 weeks at 10/7 °C plus 1 week at 20/15 °C produced 100% inflorescences. GA3(100 mg·L-1) applied to buds 2 or 4 weeks after initiation of this LT treatment did not reduce the number of inflorescences that developed. `Hass' avocado apical buds were fully committed to flowering after 4 weeks of LT, but were not distinguishable anatomically from those that were not committed to flowering.

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