Coordinated development of the architecture of the primary shoot in

bush rose

S. Demotes-Mainard*, G. Guéritaine*, R. Boumaza*, P. Favre*, V. Guérin*, L. Huché-Thélier*, B. Andrieu**

*UMR SAGAH, Angers, France** UMR EGC, Grignon, France

D I E T

A G R I C U L T U R E

E N V I R O N M E N T

In ornamental plants, the architecture is important for both plant functions and plant visual quality

Creeping or erect stature

Symmetry

Foliage density

Development, Organ extension,

Resources allocation

Perception of environment Acquisition of resources

Architecture

Plant-Environment

interface

Yield and nutritive

quality

Visual quality

Food &

fodder crops

Orn

amen

tal crops

Not mentioning other users

Growing roses in a glasshouse enables to modulate the environmental conditions

Temperature, CO2, radiation, humidity, water and nutrient supply can be manipulated

Growing roses in a glasshouse implies:

•the possibility to manipulate plant environment

•the requirement to optimize the costs linked to the glasshouse and to control the diseases and insects

=> need tools to define the best compromizes

In roses, architecture is strongly modified by environmental conditions

Sensitivity to global environmental conditions

Girault et al. (2008) Plant Cell Env. 31:1534-1544

Sensitivity to local environmental conditions

For growers:• Knowledge on how to manipulate plant architecture to match needs for:

- innovative shapes - stable, reproductible shapes

• References on how new varieties are going to behave•Methods to manipulate plant shape cheaper than pruning

For research : Rose bush as a model to investigate G*E interactions on formation of plant architecture

Objectives

• Objective of the projectTo develop a functional structural model of bush rose in order to explore the plant response to genotype × environment interactions

• Objective of the work presented hereTo produce an organized description of the kinetics of development and final dimensions of the organs forming the primary shoot of the rosebush and of their relationships

• Expected outcomes of this work:– Identification of pattern that may be stable enough to be

incorporated into a functional structural model – A parametric 3D rose model that can be used to investigate light

distribution on the plant– A grid for analyzing rose architecture in response to genotype ×

environment interactions

Material and methods

Roses (Rosa hybrida) of the ‘Radrazz’ cultivar

- Plant developmental stages

- Number of phytomers on main shoot

- Leaf shape measurements at various stages

- Detailed kinetics of extension for terminal leaflets and for internodes

2 glasshouse experiments with destructive and non-destructive measurements

Bud break from a cutting

Flowering of primary axis

Le Bris, 1999, PhD ThesisLe Bris, 1999, PhD Thesis

Simple relationships allowed to describe the sequence of leaves along the stem

Allometric relationships related all leaflet dimensions to length of terminal-leaflet

This was true when comparing mature leaves and was quite accurate for a leaf at different stages of growth

Mea

n le

afle

t num

ber

per

leaf

-1012345678

1 2 3 4 5 6 7 8 9 10 11 12 13

Phytomer rank

Mea

n le

afle

t num

ber

....

8 phytomers 9 phytomers 10 phytomers

11 phytomers 12 phytomers

Me

an

lea

flet

nu

mb

er

pe

r le

af

Base Top

Main stem consisted of between8 and 12 phytomers at flowering

The number of leaflets per leaf varied according to position along the stem, following a well defined pattern

Extension of terminal leaflets and internodeswere fitted by linear relations with thermal time

A phytomer

0

1

2

3

4

5

6

7

8

-450 -400 -350 -300 -250 -200 -150 -100 -50 0 50 100 150 200 250 300

Leng

th (cm

)

...

..

Degree days since peduncle was 1 cm

I1

I3I5

I7

I9

I10

I11

Peduncle

A3

A5 A7

A9 A11

VFB VCP SR

A6

- - - : Term. leaflet (A)

___ : Internode (I)

Within plants :- Leaflets of successive phytomers had very similar durations of extension: the variability in final size resulted only from variability in extension rates

- Internodes of successive phytomers show some variability in the duration of extension: the variability in final sizes resulted mainly from variability in extension rates and slightly from variability in duration of extension

Between plants: For plants having a same number of phytomers, variability of size resulted from variation in extension rates

A

I

Extension of terminal leaflets and internodes are coordinated

The beginning of linear growth: terminal leaflet was synchronous with the internode of the same phytomer

End of growth: terminal leaflet was synchronous with the internode of the next phytomer

-500

-400

-300

-200

-100

0

-500 -400 -300 -200 -100 0

Terminal leaflet n

Inte

rnod

e n

...

y=x

°Cd since peduncle is 1 cm

Beginning of extension

-300

-200

-100

0

100

200

-300 -200 -100 0 100 200

Terminal leaflet n

Inte

rnod

e n+

1 ......

y=x

°Cd since peduncle is 1 cm

End of extension

First L-system implementation, using L-studio

Virtual rose – UMR SAGAH – P. FavreVirtual rose – UMR SAGAH – P. Favre

Animation Rosier_0001.wmv

First implementation of a dynamic rose treeFirst L-system implementation, using L-studio

First L-system implementation, using L-studio

First L-system implementation, using L-studio

First L-system implementation, using L-studio

First L-system implementation, using L-studio

First L-system implementation, using L-studio

Implications• This works provides a framework for studying

the development of rosebushes architecture• The stability of the relationships will be

evaluated over a range of genotypes and growth conditions

• Two main types of application :– A grid for analyzing the response of rose phenotypic

development genotype × environment interactions – A dynamic, plant model that can be fitted to experimental data

and coupled with a radiative transfer model to test hypotheses on plant responses to global and local light environment

– Depending on their stability, some or all of observed patterns willl be re-used in the development of a functional plant model