Growth relationships between root and shoot in walnut seedlings (Juglans regia L.)

HAL Id: hal-02725224

https://hal.inrae.fr/hal-02725224

Submitted on 2 Jun 2020

HAL is a multi-disciplinary open access

archive for the deposit and dissemination of

sci-entific research documents, whether they are

pub-lished or not. The documents may come from

teaching and research institutions in France or

abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est

destinée au dépôt et à la diffusion de documents

scientifiques de niveau recherche, publiés ou non,

émanant des établissements d’enseignement et de

recherche français ou étrangers, des laboratoires

publics ou privés.

Growth relationships between root and shoot in walnut

seedlings (Juglans regia L.)

Jean-Sylvain Frossard, A. Charron, André Lacointe, . Inra, . Universite

To cite this version:

Jean-Sylvain Frossard, A. Charron, André Lacointe, . Inra, . Universite. Growth relationships between

root and shoot in walnut seedlings (Juglans regia L.). Annales des sciences forestières, INRA/EDP

Sciences, 1989, 46 (suppl.), pp.297s-300s. �hal-02725224�

Growth

_{relationships}

between

root

and shoot

in walnut

_{seedlings (Juglans regia}

_L.)

J.S. Frossard A. Charron

A.

Lacointe

Laboratoire de Bioclimatologie, INRA, Centre de Recherches de Ctermont-Ferrand-Theix,

Domaine-de-Crouelle, 63039 Clermont-Ferrand, France

Introduction

It is well known that the

_periodicity

of root

growth throughout

the year may be the same as or different from that of shoot

growth

(Riedacker,

1976; Kramer and

Koslowski,

1979; Frossard and

Lacointe,

1988),

depending

upon the

species.

It is

difficult to

_interpret

the

_published

results

because

_they

were obtained on trees of different ages under different climatic

conditions.

It is

_particularly

difficult to

_give

_precise

answers to the

_{following questions:}

₁₎

is the relative

_position

within the annual

cycle

of root and shoot

_growth

a

_general

characteristic of a

_{given species?}

In other

words,

is there _any evolution between

years, in the relative

periodicity

of root and

shoot

_growth?

₂₎

are the

_{relationships}

bet-ween variables

_{describing growth}

equiva-lent

_throughout

the

_year?

Answers to

these

_questions

are of

_particular

interest when

_working

on

_{seedling growth}

and when

_{investigating}

the carbon allocation to

different organs

(Lacointe, 1989).

Materials and Methods

For 3 yr (1985, 1986, 1987), walnuts were sown

in _early June, in _clay soil, and _grown in a

glass-house. After 1 mo, 10 seedlings per yr were transplanted into minirhizotrons and grown

out-doors, under natural conditions (continental

cli-mate). Root and shoot _growths were measured

weekly, during 2 yr for the 1985 and 1986

seed-lings, and _{during 1 yr for the 1987 seedlings.}

From September to March, bud _dormancy

was studied _using the MTB test

_(Bailly

and

Mauget, 1989}.

Results

There was a

_{high variability}

between

plants

during

both the 1 st _{and the 2nd yr.} An

_example

_{of between yr}

_variability

is

given

in

_Figs.

1

_(1985-1986)

and 2

(1986-1987).

However, the relative

_growth

_patterns

of the different organs were the same. There were ’l st

_yr’

and ’2nd

_{yr’ patterns.}

_During

the 1st

_growing

season

_{(sowing yr),}

root

and shoot

_growth

occurred

simultaneous-ly;

during

the 2nd season

_{(2nd yr),}

leaf

growth began

first,

followed

by

shoot

elon-gation

and root

_growth

came last.

In autumn, there was no

_relationship

between

_dynamics

of bud

_dormancy

and root

_{growth (data}

not

_shown).

No root

In order to

_specify

the

_dynamics

of

relationships

among

growth

variables,

5 French

_principal

_components

_analyses

were

_performed,

one for each of the 3

sowing

yr and one for each of the _{2nd yr}

studied: on _{the average values for the} 10 0

plants; taking

as ’individuals’ the

measure-ment dates.

The

_sowing

_yr

_{analyses provided}

3 very

similar

_figures,

and the same was true for both 2nd yr

analyses.

The results for the 1985

_sowing

are

_presented

in

_Figs.

3

(sowing yr)

and 4

_{(2nd yr).}

Comparison

of

_component

_weights

(variables)

vs

_principal

_components

us to

_interpret

the

_geometrical

relation-ships

among variables as time

relation-ships.

As an

_example,

for the

_sowing

_yr,

the number of

_growing

roots

_(NGR)

was maximal near

_August

_10,

the leaf area

(LA)

in late

_August,

the shoot

_{height (SH)}

and the shoot volume

_(SV)

in late October and the total

_length

or roots

_(TLR)

in

_early

November.

For some of

them,

such as LA or

TLR,

this

_synthetic

overview of the

_growth

dyna-mics was consistent with that which could

be derived from the

_plots

of the

consid-ered variables vs time

_(Figs.

1 and

_2).

For

SH,

however, there was a

_large

discrepan-cy: it was

_probably

related to the

_biphasic

growth

pattern

of the

shoot,

with a

_high

slower

_growth

in late summer and autumn,

which could not be detected from the

individual curves.

_Similarly,

the

discrepan-cy between the root

_growth

variables,

NGR and

TLR,

probably

reflected the root

growth

pattern:

an

_{early multiplication}

of

white

_tipped

roots, followed

_by

an active

elongation.

Discussion and Conclusion

The results show that there was an

evolu-tion between _{years in the} relative

periodi-city

of root and shoot

_growth

of walnut

seedlings.

Since there was no

_relationship

between bud

_dormancy

and root

growth,

the reasons for the cessation of

root

_{growth might}

be related to carbon allocation or to climatic

factors,

such as soil or

_temperature

_(or

_both).

The

_{specific relationships}

observed be-tween the

_growth

variables

_during

the 2

growing

seasons were characteristic of

the walnut

_seedling

and

_relatively

in-dependent

of climatic hazards because

they

were obtained in _{different years}

_(with

different

_patterns

of

_temperature

and

radiation in this continental climate, for each

_year).

Thus,

it

_might

be

_possible

to

_study

under controlled conditions

_particular

rela-tionships

between a climatic factor

_(for

example, temperature)

and

growth,

con-serving

the same _ranges as those

obser-ved under natural conditions.

References

Bailly O. & Mauget J.C. (1989)

Physiological

correlation and bud _dormancy in the _apple tree

(Malus domestic:a Borkh.). Ann. Sci. For. Forest Tree

_Physiology

46 suppl., 220s-222s Frossard J.S. & Lacointe A.

₍₁₉₈₈₎

Seasonal variations in carbon economy in

vegetative

trees under temperate climate - a review. Bull. Soc. Fr. Bot. 1, 9-24

Kramer P.J. & Kozlowski T.T. ₍₁₉₇₉₎ In: Phy

siology

of Woody Plants. Academic Press, New

York, pp. 811

1

Lacointe A. (19Et9) Assimilate allocation and carbon reserves in

_Juglans

regia L. seedlings.

Ann. Sci. For. Forest Tree

_{Physiology 46}

suppi.,

836s-840s

Riedacker A. ₍₁₉₇₆₎ Growth and _regeneration

rhythms of roots of ligneous species - a review.