Fig. 1

Comparison of the field performance of flowers and anthers from NH and its isonuclear alloplasmic near-isogenic line SH under mild HT (AY) and extreme HT (JJ) stress. A A representative intact flower from NH (left) and SH (right) under mild HT in AY. B Anthers from NH (left) and SH (right), showing normal pollen release only from NH under mild HT in AY. C, D Pollen grains from NH (C) and SH (D) plants under mild HT stress and stained with Benzidine-α-Naphthol in AY. E A representative intact flower from NH (left) and SH (right) under extreme HT in JJ. F Anthers from NH (left) and SH (right), showing normal pollen release only from NH under extreme HT in JJ. G, H Pollen grains from NH (G) and SH (H) plants under extreme HT stress and stained with Benzidine-α-Naphthol in JJ. More sterile pollen grains from SH were observed under HT stress, especially in JJ spot. Fertile pollen is stained red, part of the vitality shows reddish, and sterile pollen is colorless. Scale bars = 5 mm in A, B, E, F and 100 µm in C, D, G, H. I–K Graphical representations of the percentage of anther dehiscence (I), filament length (J), and exposed length of stigma (K) of NH and SH under mild and extreme HT stress in AY and JJ spots, respectively. AY Anyang, JJ Jiujiang