Water Transport Properties of the Grape Pedicel during Fruit Development: Insights into Xylem Anatomy and Function Using Microtomography

Knipfer, Thorsten; Fei, Jiong; Gambetta, Grégory A.; McElrone, Andrew J.; Shackel, Kenneth A.; Matthews, Mark A.

doi:10.1104/pp.15.00031

Cited by 54 publications

(60 citation statements)

References 39 publications

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“…Second, occlusion of the xylem (Knipfer et al, 2015) and xylem discontinuity in the flower receptacle (Lersten & Wemple, 1966) could provide the spatial precision needed to differentially isolate heterotrophic and autotrophic floral structures (e.g., the calyx and corolla) and to generate the large water potential gradients observed between them (Trolinder et al, 1993). In Calycanthus, however, we found no evidence of xylem occlusion or discontinuity in the xylem pathway to the flower, particularly given the high values of K flower in the genus and those measured diurnally here (Figures 3 and 4; Roddy et al, 2016).…”

Section: Discussionmentioning

confidence: 99%

Water relations of Calycanthus flowers: Hydraulic conductance, capacitance, and embolism resistance

Roddy

Simonin

McCulloh

et al. 2018

Plant Cell & Environment

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For most angiosperms, producing and maintaining flowers is critical to sexual reproduction, yet little is known about the physiological processes involved in maintaining flowers throughout anthesis. Among extant species, flowers of the genus Calycanthus have the highest hydraulic conductance and vein densities of species measured to date, yet they can wilt by late morning under hot conditions. Here, we combine diurnal measurements of gas exchange and water potential, pressure-volume relations, functional responses of gas exchange, and characterization of embolism formation using high resolution X-ray computed microtomography to determine drought responses of Calycanthus flowers. Transpiration from flowers frequently exceeded transpiration from leaves, and flowers were unable to limit transpiration under conditions of high vapour pressure deficit. As a result, they rely heavily on hydraulic capacitance to prevent water potential declines. Despite having high water potentials at turgor loss, flowers were very resistant to embolism formation, with no embolism apparent until tepal water potentials had declined to -2 MPa. Although Calycanthus flowers remain connected to the stem xylem and have high hydraulic capacitance, their inability to curtail transpiration leads to turgor loss. These results suggest that extreme climate events may cause flower failure, potentially preventing successful reproduction.

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Section: Discussionmentioning

confidence: 99%

Water relations of Calycanthus flowers: Hydraulic conductance, capacitance, and embolism resistance

Roddy

Simonin

McCulloh

et al. 2018

Plant Cell & Environment

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“…Pedicel and berry k h did not change at the onset of ripening (Choat et al , 2009; Knipfer et al , 2015). Evidently, the sudden developmental decline in xylem inflow into the berries is not due to changes in k h .…”

Section: Introductionmentioning

confidence: 94%

Discharge of surplus phloem water may be required for normal grape ripening

Zhang

Keller

2017

EXBOTJ

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“…Grapevine plants ( Vitis riparia , V. champinii , V. berlanderii ) were grown from 5‐ to 10‐cm‐long herbaceous cuttings obtained from established parent plants at the University of California, Davis's experimental vineyards (Knipfer et al ., ,b). Cuttings were transplanted into 0.7–1 l plastic pots filled with a soil mix of 40% washed sand, 20% sphagnum peat moss, 20% redwood compost, and 20% pumice rock.…”

Section: Methodsmentioning

confidence: 99%

“…Plants were scanned at the microCT facility (Beamline 8.3.2) at the Lawrence Berkley National Laboratory Advanced Light Source (ALS) (for details, see Brodersen et al ., ; McElrone et al ., ; Knipfer et al ., ,b). On the day of scanning, plants were transported from the glasshouse to the ALS around 3 h before the start of analysis.…”

Section: Methodsmentioning

confidence: 99%

“…In plants, X‐ray microCT has primarily been used to segment air, water and cell wall domains, which have low to high X‐ray absorption coefficients, respectively (Steppe et al ., ; Brodersen et al ., ; Herremans et al ., ; Théroux‐Rancourt et al ., ). As a result, previous studies employed X‐ray microCT to quantify the transition between water‐ and air‐filled vascular conduits in plant stems and leaves (Brodersen et al ., ; Knipfer et al ., 2015a), along with three‐dimensional segmentation of anatomical features in fruits, seeds, leaves, and roots (Dhondt et al ., ; Knipfer et al ., 2015b; Cuneo et al ., ; Théroux‐Rancourt et al ., ). The chemical and structural similarities between starch and cell wall material, especially cellulose, suggest that these molecules may similarly absorb X‐ray energy.…”

Section: Introductionmentioning

confidence: 99%

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In vivo quantification of plant starch reserves at micrometer resolution using X‐ray microCT imaging and machine learning

et al. 2018

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Starch is the primary energy storage molecule used by most terrestrial plants to fuel respiration and growth during periods of limited to no photosynthesis, and its depletion can drive plant mortality. Destructive techniques at coarse spatial scales exist to quantify starch, but these techniques face methodological challenges that can lead to uncertainty about the lability of tissue-specific starch pools and their role in plant survival. Here, we demonstrate how X-ray microcomputed tomography (microCT) and a machine learning algorithm can be coupled to quantify plant starch content in vivo, repeatedly and nondestructively over time in grapevine stems (Vitis spp.). Starch content estimated for xylem axial and ray parenchyma cells from microCT images was correlated strongly with enzymatically measured bulk-tissue starch concentration on the same stems. After validating our machine learning algorithm, we then characterized the spatial distribution of starch concentration in living stems at micrometer resolution, and identified starch depletion in live plants under experimental conditions designed to halt photosynthesis and starch production, initiating the drawdown of stored starch pools. Using X-ray microCT technology for in vivo starch monitoring should enable novel research directed at resolving the spatial and temporal patterns of starch accumulation and depletion in woody plant species.

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Water Transport Properties of the Grape Pedicel during Fruit Development: Insights into Xylem Anatomy and Function Using Microtomography

Cited by 54 publications

References 39 publications

Water relations of Calycanthus flowers: Hydraulic conductance, capacitance, and embolism resistance

Water relations of Calycanthus flowers: Hydraulic conductance, capacitance, and embolism resistance

Discharge of surplus phloem water may be required for normal grape ripening

In vivo quantification of plant starch reserves at micrometer resolution using X‐ray microCT imaging and machine learning

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