Bands of root hairs are produced in tomato (Lycopersicon esculentum) in response to specific combinations of thermoperiods and photoperiods

Abstract

Tomato (Lycopersicon esculentum) seedlings were grown in non‐aerated culture solution in a controlled environment under 10 different combinations of photoperiod and thermoperiod. It was found that the pattern of distribution of root hairs was controlled by the photoperiod and thermoperiod. Under a diurnal rhythm consisting of a 16/8 h photoperiod, at temperatures of 25°C/15°C, regions of the root had bands of hairs that were separated by hairless regions. After 5 days under these conditions, four bands of hairs were most commonly found. Other combinations of light and temperature also gave rise to bands of root hairs, but the bands were fewer and less defined. A lower night temperature, together with 8 h of darkness, switched off root‐hair production. These findings are consistent with the hypothesis that all epidermal cells in tomato are “switched on” for hair production, but that this state can be altered by specific environmental conditions.