Australian Journal of Botany Australian Journal of Botany Society
Southern hemisphere botanical ecosystems
RESEARCH ARTICLE

Water deficit changes the anatomy of the fruit abscission zone in Raphanus raphanistrum (Brassicaceae)

Mohammad S. Taghizadeh A B , Simon Crawford C , Marc E. Nicolas D and Roger D. Cousens A E
+ Author Affiliations
- Author Affiliations

A Department of Resource Management and Geography, The University of Melbourne, Burnley Campus, 500 Yarra Boulevard, Richmond, Vic. 3121, Australia.

B Present address: Darab Faculty of Agriculture, Shiraz University, PO Box 335, Shiraz, Iran.

C School of Botany, The University of Melbourne, Vic. 3010, Australia.

D Department of Agriculture and Food Systems, The University of Melbourne, Vic. 3010, Australia.

E Corresponding author. Email: rcousens@unimelb.edu.au

Australian Journal of Botany 57(8) 708-714 https://doi.org/10.1071/BT09165
Submitted: 18 September 2009  Accepted: 20 November 2009   Published: 8 February 2010

Abstract

Raphanus raphanistrum L. is an important agricultural weed that often matures at a time of year when water availability is decreasing rapidly. We examined the development of the abscission zone under contrasting soil water treatments and exogenous application of Ethrel. Morphometric analyses of cell traits were used to quantify the effects. Although the abscission zone was visible in sections after 2 weeks under all water regimes, it was more distinctive for pods that had developed under water deficit and Ethrel application. Pod separation began on the outside and gradually extended through the inner cells until the pod was supported only by the xylem elements. The rate of weakening of the cells accelerated where pods developed under water deficit (both mild and severe) or were treated by Ethrel. Water deficit increased the sizes of cells in and adjacent to the abscission zone, doubling their cross-sectional area from well watered to severe water deficit. Ethrel, but not water deficit, significantly increased the thickness and the number of cells across the separation layer. Abscission scar diameter increased by ~50% with increasing water deficit. Notably, we observed some plants in which no abscission zone formed.


Acknowledgements

MST was funded by a scholarship from the Iranian Ministry of Science, Research and Technology; all other costs were met by The University of Melbourne. We thank Alex Campbell for his assistance in running the experiment.


References


Addicott AB (1982) ‘Abscission.’ (University of California Press: Berkeley, CA)

Bohrer G, Katul GG, Nathan R, Walko RL, Avissar R (2008) Effects of canopy heterogeneity, seed abscission and inertia on wind-driven dispersal kernels of tree seeds. Journal of Ecology 96, 569–580.
CrossRef |

Cheam AH, Code GR (1995) The biology of Australian weeds 24. Raphanus raphanistrum L. Plant Protection Quarterly 10, 2–13.

Chèvre AM, Eber F, Baranger A, Hureau G, Barret P, Picault H, Renard M (1998) Characterization of backcross generations obtained under field conditions from oilseed rape–wild radish F1 interspecific hybrids: an assessment of transgene dispersal. Theoretical and Applied Genetics 97, 90–98.
CrossRef |

Child R, Chauvaux N, John K, Ulvskov P, Onckelen H (1998) Ethylene biosynthesis in oilseed rape pods in relation to pod shatter. Journal of Experimental Botany 49, 829–838.
CrossRef | CAS |

Cousens R , Dytham C , Law R (2008) ‘Dispersal in plants: a population perspective.’ (Oxford University Press: Oxford, UK)

Crowfoot LV (2005) Phenotypic variation in Raphanus raphanistrum L. PhD Thesis, The University of Melbourne.

Donohue K (1998) Maternal determinants of seed dispersal in Cakile edentula: fruit, plant, and site traits. Ecology 79, 2771–2788.

Ferrándiz C (2002) Regulation of fruit dehiscence in Arabidopsis. Journal of Experimental Botany 53, 2031–2038.
CrossRef | PubMed |

Greene DF, Johnson EA (1992) Fruit abscission in Acer saccharinum with reference to seed dispersal. Canadian Journal of Botany 70, 2277–2283.
CrossRef |

Kohlermann L (1950) Untersuchungen über die Windverbreitung der Früchte und samen mitteleuropäischer Waldbäume. Forstwissenschaftliches Centrelblatt 69, 606–624.
CrossRef |

Kozlowski TT (1973) ‘Shedding of plant parts.’ (Academic Press: New York)

Kuang A, Peterson CM, Dute RR (1992) Leaf abscission in soybean: cytochemical and ultrastructural changes following benzylaminopurine treatment. Journal of Experimental Botany 43, 1611–1619.
CrossRef | CAS |

Lieberman SJ, Valdovinos JG, Jensen TE (1983) A morphometric study on the effects of ethylene treatment in promoting abscission of tobacco flower pedicels. Plant Physiology 72, 583–585.
CrossRef | CAS | PubMed |

Liljegren SJ, Ditta GS, Eshed Y, Saivdge B, Bowman JL, Yanofsky MF (2000) SHATTERPROOF MADS-box genes control seed dispersal in Arabidopsis. Nature 404, 766–770.
CrossRef | CAS | PubMed |

Meakin PJ, Roberts JA (1990) Dehiscence of fruit in oilseed rape (Brassica napus L.): anatomy of pod dehiscence. Journal of Experimental Botany 41, 995–1002.
CrossRef |

Mongkolporn O, Kadkol GP, Pang ECK, Taylor PWJ (2003) Identification of RAPD markers linked to recessive genes conferring siliqua shatter resistance in Brassica rapa. Plant Breeding 122, 479–484.
CrossRef | CAS |

Nathan R, Safriel UN, Noy-Meir I (2001) Field validation and sensitivity analysis of a mechanistic model for tree seed dispersal by wind. Ecology 82, 374–388.

Nilsen ET , Orcutt DM (1996) ‘Physiology of plants under stress-abiotic factors.’ (John Wiley and Sons: New York)

Patterson SE, Bleecker AB (2004) Ethylene-dependent and -independent processes associated with floral organ abscission in Arabidopsis. Plant Physiology 134, 194–203.
CrossRef | CAS | PubMed |

Roberts JA, Ellitt KA, Gonzales-Carranza ZH (2002) Abscission, dehiscence, and other cell separation processes. Annual Review of Plant Biology 53, 131–158.
CrossRef | CAS | PubMed |

Sexton R, Redshaw AJ (1981) The role of cell expansion in the abscission of Impatiens sultani leaves. Annals of Botany 48, 745–756.

Sheldon JC, Burrows FM (1973) The dispersal effectiveness of the achene-pappus units of selected Compositae in steady winds with convection. New Phytologist 72, 665–675.
CrossRef |

Taghizadeh MS (2007) Determinants of seed dispersal distance in the weed Raphanus raphanistrum L. PhD Thesis, The University of Melbourne.

Taylor JE, Whitelaw CA (2001) Signals in abscission. New Phytologist 151, 323–340.
CrossRef | CAS |

Webster BD (1973). Anatomical and histochemical changes in leaf abscission. In ‘Shedding of plant parts’. (Ed. TT Kozlowski) pp. 45–83. (Academic Press: New York)

Woolcock JL, Cousens R (2000) A mathematical analysis of factors affecting the rate of spread of patches of annual weeds in an arable field. Weed Science 48, 27–34.
CrossRef | CAS |

Young KR (2001) Germination and emergence of wild radish (Raphanus raphanistrum L.). PhD Thesis, The University of Melbourne.








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