Figure 2.

Proper megasporogenesis and female gametophyte development (megagametophytogenesis) at three stages of flower development in ‘Panda’ and PA15 genotypes of common buckwheat under control (20 °C) and thermal stress (30 °C) conditions. Megaspore mother cell in prophase I in ‘Panda’ bud at 20 °C (arrow, a), tetrad of megaspores in ‘Panda’ bud at 20 °C (each of four cells marked with arrowhead, b), 1-nucleate embryo sac of PA15 at 20 °C (arrow, c), central cell (arrows), egg cell (arrowheads), one of the two synergids (double arrowhead) of 7-celled embryo sac in open and wilted flowers (d–f) of ‘Panda’ at 30 °C (d), ‘Panda’ at 20 °C (e), and PA15 at 30 °C (f). Paraffin sections stained with Ehrlich’s hematoxylin combined with Alcian blue. The number of analyzed flowers per treatment at each stage of development was 15–32 in two replicates.