Fig. 1

Morphological characterization and photosynthetic pigment contents of four water spinach cultivars cultured at 25 °C and 42 °C for 15 days, respectively. The four cultivars are ‘Bendi’ (a), ‘Zhuye’ (b), ‘Taiguo’ (c), and ‘Liuye’ (d). Upper panel: the whole water spinach plant of the four varieties subjected to 25 °C and 42 °C for 15 days, respectively. Lower panel: the enlarged (2X) apical bud of the corresponding water spinach plant in the upper panel. The contents of photosynthetic pigments include chlorophyll a (e), chlorophyll b (f), and carotenoid (g) of the four cultivars at 25 °C and 42 °C for 15 days, respectively. The statistical analyses were conducted in the same variety under different temperature conditions and the significant one was labelled with asterisks (*)