Fig. 2

Isolation of nuclear endosperm. a Close-up view of ovaries. 1 The 9311 ovary at 24 HAP; 2 the 9311 ovary at 48 HAP; 3 nipponbare ovary at 48 HAP; 4 nipponbare ovary at 24 HAP. b An ovary was cut at the micropyle end (5) into two parts (6), with the cutting position shown. c The tip of a glass micropipette. d Sucking out nuclear endosperm using a micropipette. Note the volume of the sucked liquid-like endosperm can be clearly observed at the tip of the micropipette. e Schematic diagram of the process of cutting ovary and extracting endosperm. 7 Ovary; 8 an isolated ovule to show its position in relation to cutting line (red line). f The isolated endosperm free nuclei from an ovary of Nipponbare pollinated with 9311 pollen at 24 HAP, showing clear rice free nuclei without contamination by other cells. g The isolated endosperm free nuclei from an ovary of Nipponbare pollinated with 9311 pollen at 48 HAP. h The isolated endosperm free nuclei from two ovules of Nipponbare pollinated with 9311 pollen at 48 HAP. The nuclei in f–h were stained with DAPI. Bar 1 mm in a, b; bar 100 µm in c, g and h; bar 250 µm in d; bar 25 µm in f