Fig 1.
Acetolyzed pollen grains from six Vitis vinifera cultivars analyzed under light microscopy.
a) Cabernet Sauvignon, b) Carménère, c) Chardonnay, d) Malbec, e) Merlot and f) Syrah. Samples were visualized at 40X magnification. Abnormal pollen grains are pointed by arrowheads.
Fig 2.
Morphology of normal (a-e,n,o) and abnormal (f-m) pollen grains from six Vitis vinifera cultivars analyzed under scanning electron microscopy.
a) Cabernet sauvignon (polar view); b) Chardonnay (sub-polar view); c) Malbec (sub-equatorial view); d) Carménère (equatorial view); e) Syrah (equatorial view); f) Carménère acolporate; g) Merlot acolporate; h) Carménère acolporate and collapsed; i) Malbec acolporate and collapsed, j) Carménère jumbo; k) Malbec bicolporate; l) Merlot irregular; m) Carménère irregular; n) Carménère anatomy of endo (germinal pore) and ectoapertures (colpi); and o) Cabernet sauvignon classical exine sculpture.
Fig 3.
Germination capability of pollen grains from two V. vinifera cultivars examined under light microscopy.
a) Cabernet Sauvignon in basal media (100x); b) Carménère in basal media (100x), c) Carménère in basal media (400x); and d) Germination rates in either basal or 1mM borate supplemented media at 25°C. Acolporate pollen grains in b) and c) are pointed by arrows. Basal: basal germination medium composed by 1mM CaCl2, 15% sucrose, pH 5.8 and 1% agar. +Bac: basal germination medium supplemented with 1mM borate. Means with different letters in d) are significantly different at p<0.05.
Fig 4.
Quantification of abnormal pollen, millerandage and fruitlet abscission rates in the V. vinifera cultivars Cabernet Sauvignon (CS), Carménère (Cm), Chardonnay (Ch), Malbec (Mb), Merlot (Mt) and Syrah (Sy) in two growing seasons (S1 and S2).
a) Abnormal pollen rates determined in samples processed by the Erdtman acetolysis method; b) PFD and fruitlet abscission rates; and c) Correlation between abnormal pollen and PFD rates (black squares) and between abnormal pollen and fruitlet abscission rates (open squares). Means with different letters are significantly different at p<0.05.
Table 1.
Effect of hormonal treatments on PFD rates, abnormal pollen rates and boron content in floral tissues from Vitis vinifera cv Carménère.
Table 2.
Grapevine VvBOR gene family and identity of encoded proteins with the reference protein AtBOR1 from Arabidopsis thaliana.
Fig 5.
Expression profiles of VvBOR1, VvBOR3 and VvBOR4 genes in vegetative (leaves and roots) and reproductive organs of Vitis vinifera cv. Carménère.
Pre-anthesis (flowers, 5 days before full bloom), anthesis (pollen depleted flowers at full bloom), setting (fruits, 2 days after pollination), pre-véraison (berries, 2 weeks after pollination) and véraison (berries, 8 weeks after pollination). The insert represent expression levels in pollen from flowers at anthesis. VvBOR1 expression in leaves was adjusted to 1 relative unit. Data represent the means of 4 biological replicates ± SD.
Fig 6.
VvBOR3 and VvBOR4 expression in response to hormone applications.
Analysis was performed on flowers at anthesis and fruits at setting from Vitis vinifera cv Carménère plants exposed to 100 μM ABA or 290 μM GA. Non-treated plants were used as a control. For each determination, expression of the respective gene in control samples was adjusted to 1 relative unit. Data represent means of 4 biological replicates ± SD.