Mathematical analysis and comparison of growth fluctuations of the aerial system of young Terminalia superba, Englers et Diels (Combretaceae)

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Mathematical analysis and comparison of growth

fluctuations of the aerial system of young Terminalia

superba, Englers et Diels (Combretaceae)

Pascale Maillard, Marie Agnes Jacques, Emile Miginiac, B. Millet, . Inra, .

Universite

To cite this version:

Pascale Maillard, Marie Agnes Jacques, Emile Miginiac, B. Millet, . Inra, et al.. Mathematical

analysis and comparison of growth fluctuations of the aerial system of young Terminalia superba,

Englers et Diels (Combretaceae). Annales des sciences forestières, INRA/EDP Sciences, 1989, 46

(suppl.), pp.202s-205s. �hal-02722707�

Mathematical

_analysis

and

_comparison

of

_growth

fluctua-tions of the aerial

_system

_{of young Terminalia}

_superba

Englers

et

Diels

_{(Combretaceae)}

P.

Maillard

1

_{M. Jacques}

₁

E.

_Miginiac

B.

Millet

2

1 _{Institut de}

Physiologie Vegetale (Phytotron),

CNRS, Gif-sur-Yvette, 9!90, and

2_{Laboratoire de}

_Botanique,

_{Institut des Sciences Naturelles,}

_pl.

_Leclerc,

_Besangon,

_{25030, France}

Introduction

Under natural

conditions,

Terminalia

superba

is a

_tropical

forest tree which shows fluctuations in

_growth

rate and in

flushing

behavior

_(Groulez

and

Wood,

1984).

This behavior and

_particularly

the

periodic

growth

cessations were

con-comitant with the

_dry

season. This

rhyth-mical

_{growth pattern}

ends in a

_monopodial

main axis and a

_particular

stratified branch

system

as described

_by

Halle and

Olde-man

₍₁₉₇₀₎

in Aubreville’s model.

In climate chambers at

_Phytotron,

Gif-sur-Yvette,

we determined the best

growth

conditions for _{young T.}

_{superba (Maillard}

et

al.,

1987).

Under these conditions

(27°C,

16

_h),

we noted fluctuations in the aerial

_growth.

Thereafter,

the purpose of our work was the detailed

_study

of the

early

developmental stages

of this tree.

Growth fluctuations were

_analyzed

on young T.

superba

using

the Fourier method and

_rhythmical

_components

of

growth

were evaluated. The

_growth

rela-tionships

between shoot and branches

and their effects on tree architecture have been

_{investigated.}

Materials and Methods

Materials

T.

_superba

seeds

_originating

from Sibiti

(Congo),

obtained from the Centre

Technique

Forestier

_Tropic:al,

_{Nogent-sur-Marne (ref.}

C.T.F.T., 82/3808

_N),

were used for the

experi-ment. Measurements were made over 1 yr, on 3

mo old

_seedling:;

in a controlled and condi-tioned

_{glasshouse (27°C,}

16 h

_photoperiod

and 70%

humidity)

at

Phytotron,

Gif-sur-Yvette.

The Fourier method

We used the method of Assaad

(1985).

The fluctuations of individual

_growth

curves obtained from

weekly

data were studied: the

_polynomial

regression

curve, which _represents the fitted

growth

curve, was calculated

by

the least squares method. The

_signal

without trend was

obtained and a subtraction

point by

point

be-tween this

_polynomial

curve and the data curve

revealed the

_growth

oscillations. Then, the

signal

without trend and the estimation of the

rhythmical

parameters

(amplitude, period)

were

Results

General observations

At the end of the

experiment,

the main

stems of the

_plants

were vertical with

great

variations in the

_length

of

constitu-tive internodes.

_Generally,

in short inter-node

_{regions, single}

or _{groups of} 2 or 3

lateral branches arose from the axil of

adjacent

leaves. These branches were

composed

of a series of

_sympodial

units

first unit arose alone

_directly

from an

axillary

bud on the

_principal

axis.

Individual

_patterns

of

_plant

main axis

elongation

showed a

_{time-lag during}

the

first 11 wk

_{(Fig. 1}

_{Then, growth}

occurred

in the

_following

21 wk with successive

flushes.

_During

the last weeks of the

ex-periment,

the

_elongation

of the main axis

slowed and entered a low

_growth

_phase

with many rest intervals. The number of these intervals varied with

_plants

but was

usually

3 or 4.

The

_development

of the first

_axillary

branches occurred from the llth to the l6th wk after the start of the

_study

_(Fig.

₁

_).

These branches

_appeared

from the axil of leaves in an area between the 30th and the 55th leaf. The dates of branch initia-tion on the

_principal

axis showed

_clearly

that

_axillary

buds were able to

_develop

only

when the

_principal

axis entered low

growth

phases

or

_during

rest

_{periods (Fig.}

1

The

subsequent

development

of initi-ated branches was made

_{by apposition}

of

new

_sympodial

units that

_appeared

at

quite regular

intervals,

regardless

of the

periodic

elongation

of the main shoot

_(Fig.

1

For

each

_{plant, weekly}

measurements of the extension of all

_axillary

branches

were used to establish a cumulative

elon-gation

curve

_{(Fig. 2).}

These curves show-ed numerous and

_pronounced

variations over the 61 wk of the

_study.

These

varia-tions

_corresponded

to the appearance and

the

_growth

of new

_plagiotropic

units or the

general growth

stoppage

of the whole

branches.

Mathematical

analysis

The nature of fluctuations observed from the aerial

_growth

has been examined

_by

Fourier

_analysis.

Results shown in Table I revealed a _{wide range in the}

_period

of the

growth

rhythm presented by

the main axis.

The values of the

_period

varied from 12 to 20 wk and

_implied

that an 8 wk

_time-lag

exists between rest

_periods

and the

resumption

of the

_activity

of the main axis.

This wide _range was also seen in the

amplitude

of the

_{growth rhythm.}

Conse-quently,

the characteristics of this

rhythmi-cal

_phenomenon

were derived from the individual behavior and

_properties

of

plants.

The

_growth

of all

_plagiotropic

branches also

_appeared

to be

_rhythmic

and

under-went

_periods

of flushes and

_stoppages.

The estimated

_period

remained

_generally

about 15 wk

_{(Table I).}

The

_amplitude

of

the cumulative

_{growth rhythm}

showed

variations for each

_plant.

For the 61 wk of the

_experiment,

com-parison

of

_signals

without trend of the

prin-cipal

axis and those of

_axillary

branches

revealed a _{gap between the} two

_rhythms

whose

_period

was not

_always

_very

dif-ferent.

_{Consequently,}

_{these organs did} not reach their maximal

_growth

rate at the same time.

Conclusion

Our results on _{the 1 st year of the}

develop-ment

_present

the young T.

_superba

as a

monopodial

axis with

_plagiotropic

bran-ches,

both

_undergoing

successive flushes. These results

_supported

the

_preliminary

description

of adult

_{Terminaliaplants}

esta-blished

_by

Halle and Oldeman

_(1970).

This discontinuous

_development

occurred under non-seasonal conditions and its

underlying

mechanism could be due to the tree itself. The Fourier

_analysis

used

made the

_rhythmical

characteristics of the

aerial

_{growth prominent}

and allowed the

estimation of

_rhythmical

_parameters

under the environmental conditions used. A second

_type

of

_{analysis (for example,}

the modern

_{spectral analysis}

_{employed by}

Assaad

_(1985))

could be _necessary to

compare and to confirm the

reliability

of the estimated values of

_rhythms.

Our

observations indicate that the

_rhythmical

branching growth

was

_directly

related to

the main axis flushes. In

fact,

the young branches were initiated as often as the

growth

of the main stem

_began

to de-crease. Such a behavior was also noted in

Terminalia

_by

Tomlinson

₍₁₉₇₆₎

and

probably

indicated correlative influences

notably

exerted between

_axillary

and ter-minal buds.

_Finally,

the stratified branch

system

borne on a

_single

_{trunk of young} T.

_superba

with these sub-verticills of lateral branches was

_partly

_{explained by}

this discontinuous

_growth

_pattern.

Acknowledgments

The C.T.F.T., the

forestry

department

of the C.I.R.A.D.

_(France),

is

_duly

acknowledged

for its financial

_{participation.}

References

Assaad C.

(1985)

Organisation

temporelle

de la tomate

(Lycopersicon

esculentum Mill. cv.

_Ace)

au cours de sa croissance et de son

d6velop-pement. Ph.D. Thesis, Université Franche

Comt6, France

Groulez J. & Wood P.J.

₍₁₉₈₄₎

In:

Monogra-phie

du Terminalia

superba.

G.T.F.T., C.F.L, Ed.

Frangaise,

pp. 85

Halle F. & Oldeman R.A.A.

(1970)

Essai sur

I’ar-chitecture et la

_dynamique

de croissance des arbres

_{tropicaux. Monogr.}

Bot. Biol.

Vdg.

Mas-son, Paris, pp. 178

Maillard P.,

Jacques

M. &

_Miginiac

E.

₍₁₉₈₇₎

Croissance de

jeunes

Terminatia

superba

en

conditions contr6l6es. Ann. Sci. For. 44, 67-84

Tomlinson P.B.

_{(1976) Branching}

and axis dif-ferentiation in

_tropical

trees. In:

_Tropical

Trees

as

Living Systems. (Tomlinson

P.B. &

Zimmer-man _M.H.,

_eds.),

_Cambridge

Univ. Press,