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Abstract
Drought reduces plant and cell elongation. Our objective was to quantify the effects of drought on elongation and gibberellin homeostasis. We exposed tomatoes to drought to observe the effect on elongation and gibberellin metabolism-related gene expression. Plants were maintained at substrate moistures to provide well-watered or drought conditions. To further investigate the effect of gibberellins on elongation, paclobutrazol (PAC) was applied, reducing gibberellin production. Drought reduced height (P = 0.0012) under drought, and had an interactive effect with PAC on internode length (P = 0.0004), and cell size (P = 0.0067). We analyzed the transcription of SlGA20ox1, -2, -3, and -4, SlGA3ox2, and SlGA2ox2, -4, and -5, corresponding to gibberellin biosynthesis. Transcription of LeEXP1, and -2, encoding for expansin enzymes, was also analyzed. Down regulation of transcription due to stress was observed for SlGA20ox4, SlGA2ox5, and LeEXP1. These findings emphasize the inhibiting effect drought has on elongation during vegetative growth.