Fig. 1
From: Induction of unreduced megaspores with high temperature during megasporogenesis in Populus
Female bud development of Populus pseudo-simonii × P. nigra ‘Zheyin3#’ (Bar = 5 mm). a Stage I bud, which is tightly wrapped by bract scales; b stage II bud with slight bulge in the middle; c stage III bud with slightly dehisced bract scales; d stage IV bud with a slightly emerged catkin; e stage V bud, characterized by approximately one third of the catkin outside of bract scales; f stage VI bud with approximately half of the catkin outside of bract scales; g stage VII bud with approximately two third of the catkin emerged outside the bract scales