2.1 Plant material and growth conditions
J. auriculatum plants were cultivated in the experimental field of the department at Indian Institute of Technology Kharagpur, India. All the experiments were carried out in the summer of 2018 and 2019 subsequently. The flowering occurs from May and lasts till August. The average lowest and highest temperatures of the region during May-June ranged between 24±3°C to 36±3°C respectively and the average relative humidity during this period was around 78%, respectively. The in situ experiments were carried on flowers of field-grown plants under natural day-light conditions from six different floral maturation stages namely, early bud: Stage 1 (S1), mid-bud: Stage 2 (S2), late bud: Stage 3 (S3), flower blooming: Stage 4 (S4), fully bloomed flower: Stage 5 (S5) and senescing flower: Stage 6 (S6). Flowers of S1 was observed one day prior to flower blooming; S2 was observed at morning on the day of flower blooming; S3 was in the afternoon on the day of flower blooming; S4 was in the evening at the time of flower blooming; S5 was in the night on the day of flower blooming; S6 was observed the next morning of flower blooming.
For controlled-temperature related studies, the plants were acclimatized for five days at particular air temperature in a growth chamber (LabTech India Pvt. Ltd.). The plants were incubated under four different temperature conditions 20°C, 25°C, 30°C and 35°C respectively, where relative humidity of 70%, light intensity of 2000 lux (maintained via cool white fluorescent lamps) and 12h/ 12h (06.00 h - 18.00 h/ 18.00 h - 06.00 h) light/dark cycle was maintained.