Annals of Botany 93: 275-282, 2004
© 2004 Annals of Botany Company
Causes and Effects of Changes in Xylem Functionality in Apple Fruit
ETA1,21 HortResearch, Palmerston North Research Centre, Private Bag 11 030, Palmerston North, New Zealand, 2 Institute of Molecular BioSciences, Massey University, Private Bag 11 222, Palmerston North, New Zealand and 3 HortResearch, Havelock North Research Centre, Private Bag 1401, Havelock North, New Zealand
* For correspondence. E-mail P.E.Jameson{at}massey.ac.nz
Received: 14 August 2003;; Returned for revision: 8 October 2003; Accepted: 26 November 2003
Background and Aims The xylem in fruit of a number of species becomes dysfunctional as the fruit develops, resulting in a reduction of xylem inflow to the fruit. Such a reduction may have consequential effects on the mineral balance of the fruit. The aim of this study was to elucidate the dynamics and nature of xylem failure in developing apples (Malus domestica) showing differing susceptibilities to bitter pit, a calcium-related disorder.
Methods Developmental changes in xylem functionality of the fruit were investigated in Braeburn and Granny Smith apples by using a dye infusion technique, to stain the vasculature along the path of dye movement. The vascular bundles were clearly visible in transverse section when fruit were sectioned equatorially. The intensity of staining of the vascular bundles in the fruit was recorded at regular intervals throughout the season. Tissue containing dysfunctional bundles was fixed and embedded in wax for subsequent sectioning and examination.
Key Results As the season progressed, an increasing proportion of vascular bundles failed to show any staining, with the most marked change occurring in the primary bundles, and in nearly all bundles with increasing distance from the stalk end of the fruit. Decreased conductance in the primary bundles of Braeburn occurred earlier than in Granny Smith. Microscopy revealed that the xylem in vascular bundles of the fruit suffered substantial damage, indicating that the mode of dysfunction was via the physical disruption of the xylem caused by expansion of the flesh.
Conclusions Results support the view that the relative calcium deficiency of apple fruit is due to a progressive breakdown of xylem conductance caused by growth-induced damage to the xylem strand in the bundle. The earlier onset of xylem dysfunction in the cultivar more susceptible to bitter pit suggests that the relative growth dynamics of the fruit may control the occurrence of calcium-related disorders.
Key words: Malus domestica, apple, apoplastic dye, xylem functionality, vascular bundles, calcium, bitter pit.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
P. Verboven, G. Kerckhofs, H. K. Mebatsion, Q. T. Ho, K. Temst, M. Wevers, P. Cloetens, and B. M. Nicolai Three-Dimensional Gas Exchange Pathways in Pome Fruit Characterized by Synchrotron X-Ray Computed Tomography Plant Physiology, June 1, 2008; 147(2): 518 - 527. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. S. Chatelet, T. L. Rost, K. A. Shackel, and M. A. Matthews The peripheral xylem of grapevine (Vitis vinifera). 1. Structural integrity in post-veraison berries J. Exp. Bot., May 1, 2008; 59(8): 1987 - 1996. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Morandi, M. Rieger, and L. C. Grappadelli Vascular flows and transpiration affect peach (Prunus persica Batsch.) fruit daily growth J. Exp. Bot., November 23, 2007; (2007) erm248v1. [Abstract] [Full Text] [PDF] |
||||
![]() |
M Genard, N Bertin, C Borel, P Bussieres, H Gautier, R Habib, M Lechaudel, A Lecomte, F Lescourret, P Lobit, et al. Towards a virtual fruit focusing on quality: modelling features and potential uses J. Exp. Bot., March 1, 2007; 58(5): 917 - 928. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Keller, J. P. Smith, and B. R. Bondada Ripening grape berries remain hydraulically connected to the shoot J. Exp. Bot., August 1, 2006; 57(11): 2577 - 2587. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. R. Bondada, M. A. Matthews, and K. A. Shackel Functional xylem in the post-veraison grape berry J. Exp. Bot., November 1, 2005; 56(421): 2949 - 2957. [Abstract] [Full Text] [PDF] |
||||

