Vascular network in the pericarp of tomato fruit and implications for fruit size, quality, and drought response

The importance of the vascular network for transporting water,
carbohydrate, and nutrient for sustaining plant growth and development in
the vegetative body of plants is well known. Nevertheless, the vascular
network within a fruit is still inadequately
understood. Here we characterized the vascular
network in the fruit pericarp of ten tomato genotypes
varying in fruit size from 20 to 287 g (fresh mass) and
investigated its relation with typical hydraulic and anatomical traits
under well-watered and water deficit conditions. We found that
larger fruits had lower vein length density, accompanied by more
xylem vessels within a vascular bundle and lower water uptake capacity per
fresh mass. Vein length density was positively
correlated with total soluble solids while negatively correlated with
mesocarp cell size. This study highlights the association between
hydraulic function of the fruit peripheral vascular network
and fruit size, likely opening up a new research avenue for
understanding fruit evolution, aiding in selection for drought-tolerant
genotypes, and encouraging integration of fruit venation patterns into
research.