The tomato plants were divided into three parts at the six-leaf
stage, where in each part has 30 pots. Two parts were subjected
to LNT treatment at 9 and 6 ◦C by transferring to a phytotron.
The treatment was done for 12 h daily (from 18:00 h to 06:00 h)
for 9 d. The environmental conditions were as follows: a 12 h
photoperiod with a photosynthetic photon flux density (PPFD)
of 600 mol m−2 s−1, temperatures of 25 ◦C/9 ◦C and 25 ◦C/6 ◦C
(day/night), and a relative humidity of 60%. Another group of plants,
also in a phytotron, was used as the control. These plants were
subjected to 25 ◦C/15 ◦C day/night temperature and the environmental
conditions described above.