Indicators of nitrogen status for ornamental woody plants

Indicators of plant nitrogen (N) status adapted to woody ornamental plants are essential to adjust fertilization to plant N demand in ornamental plant nurseries. N supply influences the synthesis of both proteins and polyphenols, because their biosynthetic pathways share a common precursor

What are the contributions of cytokinins, abscisic acid and sugars in bud outgrowth regulation by light intensity in rose?

In ornamentals, particularly in rose bush, the visual quality of a plant is an important element of its quality. Bud outgrowth, which is at the origin of branching, strongly impacts plant shape and compactness, that are two traits involved in rosebush visual quality (Boumaza et al. 2009).Changes in the environmental conditions, in particular in light intensity, can impact the number of buds that grow out and change bud outgrowth gradient along a stem in various species, including rose (Leduc et al. 2014; Furet et al. 2014). Bud outgrowth is controlled by a network of interacting hormones, the principal ones are auxin, cytokinins and strigolactones, but the role of abscisic acid is also emerging. Sugars are involved in bud outgrowth regulation too and they interact with the hormonal network. A natural hypothesis is that decreasing light intensity may limit bud outgrowth via a shortage in sugars and changes in plant hormonal content. However, the mechanisms by which light intensity affects bud outgrowth, especiallythe respective role of the different hormones and sugars in this regulation, is still poorly understood.The objective of this work was to test if the control of bud outgrowth gradient along the stem by light intensity is mediated by sugars, cytokinins and/or abscisic acid and to assess which of these actors is the main limiting actor. The study was conducted on whole plants and attention was paid to the location of bud outgrowth along the shoot

BRANCHED1: A Key Hub of Shoot Branching

Shoot branching is a key process for plant growth and fitness. Newly produced axes result from axillary bud outgrowth, which is at least partly mediated through the regulation of BRANCHED1 gene expression (BRC1/TB1/FC1). BRC1 encodes a pivotal bud-outgrowth-inhibiting transcription factor belonging to the TCP family. As the regulation of BRC1 expression is a hub for many shoot-branching-related mechanisms, it is influenced by endogenous (phytohormones and nutrients) and exogenous (light) inputs, which involve so-far only partly identified molecular networks. This review highlights the central role of BRC1 in shoot branching and its responsiveness to different stimuli, and emphasizes the different knowledge gaps that should be addressed in the near future

Rendimiento potencial de cultivares de trigo argentinos y europeos en Balcare y Grignon

*INRA Unité Agronomie Grignon (FRA) Diffusion du document : INRA Unité Agronomie Grignon (FRA)International audienc

Wheat kernel number under various nitrogen nutrition conditions: relationship to spike dry matter and nitrogen accumulation

Poster *INRA Agronomie Grignon (FRA) Diffusion du document : INRA Agronomie Grignon (FRA)International audienc

Incorporating radiation and nitrogen nutrition into a model of kernel number in wheat

International audienceWheat (Triticum aestivum L.) kernel number per square meter (KN) depends on radiation, temperature, and crop N nutrition. Some models of KN using climatic data or N nutrition characteristics as input variables account for variations either in radiation and temperature or in N nutrition, but not for both. Our objective was to produce a model of KN that accounts simultaneously for variations due to radiation, temperature, and crop N nutrition, and that has input variables that are simple to measure or to simulate. Field experiments were conducted over 3 yr with ‘Trémie’ winter wheat. Treatments involved the application of N fertilizer at different dates and rates to achieve various N deficiencies and the use of shading nets for various periods during spike growth to reduce incident radiation. Crop N status was assessed by determining N nutrition index (NNI) at anthesis. The KN was counted, it ranged from 9420 to 31 036 kernels m−2 Two characteristics of N nutrition (NNI at anthesis and IDD, the duration of deficiency before anthesis multiplied by its intensity) and three characteristics of radiation and temperature (photothermal quotient calculated from 45 d before anthesis to anthesis, from 30 d before anthesis to anthesis and from 20 d before anthesis to 10 d after anthesis) were used as input variables. Six relationships combining one characteristic of N nutrition and the photothermal quotient over one period were estimated. The best fit was obtained for a relationship between KN and the logarithm of NNI at anthesis and photothermal quotient over the 45 d preceding anthesis (R2 = 0.883, n = 19). This relationship could be useful for estimating KN in crop models, as its input variables are simple to simulate

Partitioning of dry matter and nitrogen to the spike throughout the spike growth period in wheat crops subjected to nitrogen deficiency

International audienc

Elaboration du nombre de grains du blé en situation de nutrition azotée variée pendant la période de croissance de l’épi

Elaboration du nombre de grains du blé en situation de nutrition azotée variée pendant la période de croissance de l’épi. Colloque franco-argentin : écophysiologie des cultures et des prairies naturelle