Adaptation of Arabidopsis Plants to Tropical Aeroponics Using Cool Root Zone Temperatures

Arabidopsis thaliana (L.) Heyhn. is a well knownmodel plant in plant research. However, its growth conditions and diminutivestature associated with low biomass at maturity make it a challenging speciesfor physiological studies. While in the tropical countries, it can only begrown either by tissue cultures or in growth chambers under controlledconditions. An aeroponic technique with 20°C ± 2°C and 30°C± 2°C root-zone temperatures (RZT) was used to grow Arabidopsis (Columbia ecotype) in atropical greenhouse with natural irradiance and high ambient temperature (38°C/28°Cday/night). Seedlings germinated in growth chambers at 20°C or 30°C.At 6 to 8 leaf stage, they were transferred to the aeroponic troughs with theirroots exposed to constant temperature of 20°C ± 2°C and 30°C± 2°C while their aerial parts were subjected to fluctuating ambienttemperature from 28°C to 38°C. After a week, plants haveacclimatised to both RZTs and started developing normal rosettes, bolted andyielded viable seeds. However, 20°C ± 2°C RZT allowed them torecover from turgor pressure despite of wilting, and significantly increasedbiomass. Mature plants grown in each RZTs were compared morphologically andphysiologically to the plants grown in growth chamber (GC) at 20°C(root and shoot) temperature with 60% relative humidity. Aeroponically grownplants did not experience photoinhibition, and also exhibited higher photosynthetic light usage efficiency and higher capacities of heatdissipation, compared to GC plants. Thisaeroponics with cool RZTs can allow the use of Arabidopsis as a model plant even under tropical climate.