Growth Conditions
Clones of Bignonia
magnifica were obtained from cuttings of a single plant cultivated at
the gardens of the Biosciences Institute of the University of São Paulo,
Brazil (23.56o S, 46.73o W). The
average annual temperature in the region is 21.5oC and
the mean total annual precipitation is approximately 1600 mm (Brazil
National Weather Institute –
www.inmet.gov.br).
Sixteen one-year-old plants, each measuring one meter in height, were
transplanted to pots measuring 60 cm in diameter and 50 cm in height
with soil rich in organic matter in April 2016 (Fig. 2a). Six of these
plants were grown with physical supports (stainless-steel wire meshes,
2.1 mm diameter wire, 7x7 cm mesh, Fig. 2b) for two years: five plants
were used for self-supporting and lianescent secondary xylem anatomy
analysis, and one plant was selected for the collection of cambium and
differentiating xylem samples for transcriptome assembling and
differential gene expression analysis. The remaining ten plants had
their lateral branches and main stem apices pruned to stimulate the
production of new branches of the same age (Fig. 2c). These ten plants
were divided into two groups for the analysis of physical support impact
on the lianescent xylem formation: one group was grown with physical
supports (Fig. 2d), and the other group was grown without support aid
(Fig. 2e). Pots were spaced 1.5 m apart and were watered to a maximum
field capacity three times a week for the first year and weekly
thereafter.