Relationships between xylem vessel characteristics, calculated axial hydraulic conductance and size-controlling capacity of peach rootstocks

Background and Aims Previous studies indicate that the size-controlling capacity of peach rootstocks is associated with reductions of scion water potential during mid-day that are caused by the reduced hydraulic conductance of the rootstock. Thus, shoot growth appears to be reduced by decreases in s...

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Bibliographic Details
Published in:Annals of botany 2010-02, Vol.105 (2), p.327-331
Main Authors: Tombesi, Sergio, Johnson, R. Scott, Day, Kevin R., DeJong, Theodore M.
Format: Article
Language:English
Subjects:
Dwarfing
Genotypes
hydraulic conductance
Hydraulics
Original
Plant roots
Plant Roots - anatomy & histology
Plant Roots - physiology
Plant Shoots - anatomy & histology
Plant Shoots - physiology
Plant Stems - anatomy & histology
Plant Stems - physiology
Poiseuille–Hagen
Prunus
Prunus - anatomy & histology
Prunus - physiology
Root growth
rootstock
Rootstocks
Tree trunks
vessel diameter
Visual fields
Xylem
Xylem - anatomy & histology
Xylem - physiology
xylem anatomy
Xylem vessels
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Summary:Background and Aims Previous studies indicate that the size-controlling capacity of peach rootstocks is associated with reductions of scion water potential during mid-day that are caused by the reduced hydraulic conductance of the rootstock. Thus, shoot growth appears to be reduced by decreases in stem water potential. The aim of this study was to investigate the mechanism of reduced hydraulic conductance in size-controlling peach rootstocks. Methods Anatomical measurements (diameter and frequency) of xylem vessels were determined in shoots, trunks and roots of three contrasting peach rootstocks grown as trees, each with different size-controlling characteristics: ‘Nemaguard’ (vigorous), ‘P30-135’ (intermediate vigour) and ‘K146-43’ (substantially dwarfing). Based on anatomical measurements, the theoretical axial xylem conductance of each tissue type and rootstock genotype was calculated via the Poiseuille–Hagen law. Key Results Larger vessel dimensions were found in the vigorous rootstock (‘Nemaguard’) than in the most dwarfing one (‘K146-43’) whereas vessels of ‘P30-135’ had intermediate dimensions. The density of vessels per xylem area in ‘Nemaguard’ was also less than in ‘P30-135’and ‘K146-43’. These characteristics resulted in different estimated hydraulic conductance among rootstocks: ‘Nemaguard’ had higher theoretical values followed by ‘P30-135’ and ‘K146-43’. Conclusions These data indicate that phenotypic differences in xylem anatomical characteristics of rootstock genotypes appear to influence hydraulic conductance capacity directly, and therefore may be the main determinant of dwarfing in these peach rootstocks.
ISSN:0305-7364
1095-8290
DOI:10.1093/aob/mcp281