The kiwifruit (Actinidia sp.) vine root system: Responses to vine manipulations

Black, Marykate Z.

The kiwifruit (Actinidia sp.) vine root system: Responses to vine manipulations

dc.contributor.advisor	Clearwater, Michael J.
dc.contributor.advisor	Minchin, Peter
dc.contributor.advisor	Patterson, Kevin
dc.contributor.advisor	Gould, Kevin
dc.contributor.author	Black, Marykate Z.
dc.date.accessioned	2012-02-13T01:03:44Z
dc.date.available	2012-02-13T01:03:44Z
dc.date.issued	2012
dc.date.updated	2012-01-30T23:17:59Z
dc.description.abstract	The root system is a significant component of whole-plant biomass in kiwifruit vines and is likely to be a considerable carbohydrate sink. Seasonal trends in root growth were investigated to infer seasonal fluctuations in root carbohydrate demand. Root growth peaked in summer and autumn. Observations indicate that peak root demand for carbohydrates occurs when fruit demands are also high. This infers competition between fruit and root growth, disagreeing with observations in other species. Carbohydrate partitioning between fruit and roots was studied in small kiwifruit plants using the tracer 14C. Simultaneous tracer import was observed into fruit and roots. When half the root system was cut off, root system import was reduced. The fruit imported a larger proportion of the available tracer, whilst there was no change in import into the remaining root half. Simultaneous carbohydrate import into fruit and roots demonstrated competition between these sinks. However, increased carbohydrate import into fruit suggests that the fruit has higher priority. The findings of this research suggest that the root system is a more competitive sink in kiwifruit vines than in some other fruit crops. Trunk girdling and root pruning are used to improve kiwifruit vine productivity. The effects of these practices on vine physiology, and root growth and function were investigated. Girdling reduced photosynthesis, with reductions attributed to stomatal limitation and feedback inhibition. Repeat annual girdling reduced root biomass by approximately 59%. Root growth rates were not affected, however, girdled vines produced less root tips. This suggests that new root production is more of a carbon expense than root extension. Root pruning reduced whole-vine hydraulic conductance. As treatment severity increased, reduced photosynthesis was evident, attributed to reduced sink demand. Roots in other species have demonstrated rapid changes in hydraulic conductance in response to environmental stresses. Hydraulic conductance in intact roots of kiwifruit vines did not respond when 80% of root biomass was removed. However, sap flow increased to a rate approximately 50% higher than pre-treatment. Kiwifruit roots exhibited hydraulic redundancy, which may be a stress tolerance mechanism.
dc.format.mimetype	application/pdf
dc.identifier.citation	Black, M. Z. (2012). The kiwifruit (Actinidia sp.) vine root system: Responses to vine manipulations (Thesis, Doctor of Philosophy (PhD)). University of Waikato, Hamilton, New Zealand. Retrieved from https://hdl.handle.net/10289/6012	en
dc.identifier.uri	https://hdl.handle.net/10289/6012
dc.language.iso	en
dc.publisher	University of Waikato
dc.rights	All items in Research Commons are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.
dc.subject	root
dc.subject	kiwifruit
dc.subject	hydraulic conductance
dc.subject	root pruning
dc.subject	trunk girdling
dc.title	The kiwifruit (Actinidia sp.) vine root system: Responses to vine manipulations	en
dc.type	Thesis
pubs.place-of-publication	Hamilton, New Zealand	en_NZ
thesis.degree.grantor	University of Waikato
thesis.degree.level	Doctoral
thesis.degree.name	Doctor of Philosophy (PhD)