Dissertation
MECHANISMS OF WATER MOVEMENT IN GRAPEVINES DURING OSMOHYDRAULIC REDISTRIBUTION
Doctor of Philosophy (PhD), Washington State University
01/2020
Handle:
https://hdl.handle.net/2376/111616
Abstract
Grapevines redistribute water from roots in wet soil to roots in dry soil, but it is unknown whether water movement in the phloem contributes to this water redistribution. This study investigated: 1) Xylem and phloem contributions to water redistribution and root longevity during water stress; 2) Effect of reduced root volume on vine water status; 3) Root sink strength effect on water redistribution; 4) Daytime versus nighttime water redistribution. Own-rooted Vitis vinifera Merlot and Cabernet Sauvignon grapevines were split along the trunk to create three or two rooted sub-trunks and planted into split pots with three or two compartments, respectively. In one set of experiments, one compartment was irrigated and the other two were left to dry. The sub-trunk in one of the dry compartments was girdled and the other one was left intact to distinguish xylem and phloem water movement. In other experiments, one compartment was irrigated and the other one was left to dry. The dry compartment in one experiment was heated or cooled to manipulate root sink strength. Another experiment was conducted with or without light for 12 hours. Deuterated water (2H2O) was applied to the irrigated pot compartment, and deuterium enrichment (δ2H) was analyzed in xylem and phloem sap, trunk and root tissue, and soil. Both xylem and phloem sap collected from the same petiole were enriched with 2H. Soil and root water in the dry intact compartment had higher δ2H, and roots survived much longer, than in the dry girdled compartment. Moreover, 2H was higher in water and solid tissue samples from warm roots than cool roots, and 2H was higher during the day than at night. Vines with reduced root volume did not experience severe water stress and increased water use efficiency. Collectively, these data support the idea of water movement from wet roots to leaves via the xylem and from leaves to dry roots via the phloem in addition to xylem/apoplastic water movement. Such water delivery from wet to dry roots increases longevity of dry roots and delays the onset of plant water stress.
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Details
- Title
- MECHANISMS OF WATER MOVEMENT IN GRAPEVINES DURING OSMOHYDRAULIC REDISTRIBUTION
- Creators
- Nataliya Shcherbatyuk
- Contributors
- Markus Keller (Advisor)Amit Dhingra (Committee Member)John Fellman (Committee Member)Michelle Moyer (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Horticulture, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 192
- Identifiers
- 99900581812801842
- Language
- English
- Resource Type
- Dissertation