Article Figures & Data
Figures
- Figure 1
Time course of water-stress symptom development of leaves of uninfected Chardonnay grapevines. (A) Leaves were green and turgid before the onset of water deficit. (B) As vines became water stressed, leaves became chlorotic. (C) Extensive and uniform chlorosis developed as water deficit continued. (D) Water-stressed leaf blades and petioles eventually became necrotic; dead leaves remained on the stem.
- Figure 2
Two sites of constriction and necrosis form on a petiole during water deficit. An abscission zone (A, B) developed at the stem/petiole junction. At the petiole/leaf blade junction the tissue constricted and concurrently became necrotic (C, D) during water deficit; however, no abscission or constriction occurred in nonstressed healthy plants (E, F). (B) 4x magnification; longitudinal section through the separation layer of the basal (stem) end of an abscised petiole from a water-stressed vine. X: xylem, CE: region of cell enlargement, PL: protective layer, scale bar: 0.25 mm. (D) 10x magnification; longitudinal section through the distal (leaf blade) end of a petiole from a water-stressed plant (see boxed area in C). No separation layer is present near the fracture area. Arrow indicates possible early formation of a protective layer. X: xylem, scale bar: 0.1 mm. (F) 4x magnification; longitudinal section through petiole/leaf blade junction of an intact leaf showing transition between petiolar xylem and xylem of the leaf blade including anastomosis into the five major leaf veins. PX: petiole xylem, LX: leaf blade xylem, scale bar: 0.25 mm.
- Figure 3
Uninfected Chardonnay vines from which water was withheld. (A) Wilting started with the tendrils, then summer laterals, followed by the main stem leaves. (B) Leaves and petioles of rapidly dried vines remained green as they desiccated and detached from the plant at the stem/petiole junction after nine days without water.
- Figure 4
(A) Necrotic areas at both ends of the petiole of uninfected vines from which water was withheld. (B) Abscission zone at the stem/petiole junction. (C) Constriction and necrosis at the petiole/leaf blade junction.
- Figure 5
(A) Uniformly developed periderm of uninfected control. (B) Irregular periderm development of well-watered infected Chardonnay shoot, resulting in a green island.
- Figure 6
Progressive development of leaf symptoms of PD. (A) Leaf-scorch symptoms began with chlorosis at the leaf margins. (B) Chlorosis moved toward the petiole in patches, such that sections of necrotic tissue were bordered by narrow regions of chlorotic tissue. (C, D) As symptoms progressed, leaf blades became totally necrotic, yet petioles remained green.
- Figure 7
(A) Necrotic leaf blade with a green and turgid petiole on infected vine. (B) Constriction and necrosis at the petiole/leaf blade junction, but no abscission zone at the stem/petiole junction. (C) Matchstick formed after the leaf blade dropped.
- Figure 8
Turgid leaf of uninfected Chardonnay 13 days after severance of all but one vein, resulting in a single leaf vein connecting and supplying water to half the leaf.
- Figure 9
Stomatal conductance (A) and transpiration (B) of infected (+Xf) and uninfected (−Xf) Chardonnay vines subjected to three watering regimes: well watered (ww), moderate water deficit (m), or severe water deficit (s). Measurements taken at 30 and 91 days after inoculation (DAI). Data are means ± standard errors (n = 3–7). Same letters in each graph represent data that are statistically the same at p = 0.05.
- Figure 10
Leaf water potential of infected (+Xf) and uninfected (−Xf) Chardonnay vines subjected to three watering regimes: well watered (ww), moderate water deficit (m), or severe water deficit (s). Data are means ± standard errors (n = 4–13). The same letters represent data that are statistically the same at p = 0.05.
- Figure 11
Pierce’s disease symptoms in infected Chardonnay vines in three conditions: well-watered (+Xf ww), moderate water deficit (+Xf m), or severe water deficit (+Xf s). (A) Severity of symptoms (1 = mild, 10 = severe). (B) Percentage of vines displaying PD symptoms for plants infected with X. fastidiosa. Data are means ± standard errors (for A, n = 4–7; for B, n = 5–10). The same letters in each graph represent data that are statistically the same at p = 0.05. Uninfected vines exhibited no symptoms and data are not shown.
Tables
- Table 1
Stomatal conductance and transpiration of uncut leaves and leaves 14 days after all veins but one were severed in each leaf such that a single leaf vein was the sole water source for the nearly severed portion of the leaf in healthy (−Xf) and Xf-infected (+Xf) grapevines in the greenhouse. Data are means ± standard error (n = 3–13); p = 0.05.
Uncut leaves Multivein leaf halves One-vein leaf halves −Xf +Xf −Xf +Xf −Xf +Xf Stomatal conductance (cm s−1) 0.30 ± 0.04a 0.34 ± 0.06a 0.37 ± 0.05a 0.29 ± 0.03a 0.14 ± 0.03b 0.15 ± 0.03b Transpiration (μ g cm−2 s−1) 3.21 ± 0.43a 3.49 ± 0.60a 3.78 ± 0.51a 3.20 ± 0.30a 1.82 ± 0.41b 1.65 ± 0.37b
Vol 57 Issue 1
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