PT  - JOURNAL ARTICLE
AU  - Tintu Baby
AU  - Cassandra Collins
AU  - Stephen D. Tyerman
AU  - Matthew Gilliham
TI  - Salinity Negatively Affects Pollen Tube Growth and Fruit Set in Grapevines and Cannot Be Ameliorated by Silicon
AID  - 10.5344/ajev.2015.15004
DP  - 2016 Jan 05
TA  - American Journal of Enology and Viticulture
PG  - ajev.2015.15004
4099  - http://www.ajevonline.org/content/early/2015/12/23/ajev.2015.15004.short
4100  - http://www.ajevonline.org/content/early/2015/12/23/ajev.2015.15004.full
AB  - Soil salinity decreases viticultural production by reducing vegetative growth and yield parameters such as bud fruitfulness, bunch number per cane, bunch weight and berry weight. However, how salinity affects flower fertility, berry set and berry development, and how this impacts fruit yield is yet to be determined. While the ability of silicon (Si) to enhance salt tolerance as well as yield performance is well-documented for some crops we investigated whether Si could be used as a tool for improving grapevine reproductive performance, particularly under saline conditions. One-year-old Shiraz (Vitis vinifera L.) cuttings were grown in controlled conditions and treated with salt (35 mM NaCl) and/or Si (1.5 mM K2SiO3) from budburst to veraison. Salt stress reduced fruit set by increasing flower abscission and interrupting normal berry development, which results in more live green ovaries (LGOs) and seedless berries in a bunch. Both in vitro and in vivo studies confirmed that the poor berry development due to impaired fertilization correlated to poor pollen tube growth in the style, while pollen viability and stigma receptivity were not affected by salinity. A significantly higher amount of sodium (Na+) and chloride (Cl ) ions were found in leaves and flowers after salt treatment. Silicon did not restrict the Na+ and Cl accumulation in the reproductive organs or ameliorate the deleterious effects of salinity on reproductive capacity. However, we did observe improved instantaneous water use efficiency (A/E) in Si treated vines compared to control vines. This study suggests that fertilisation is sensitive to salt accumulation and this should be avoided to minimise salinity impacts on fruit yield in the field.