b 紧学 柠 e (0 (g) Figure5 Pollen fertility(100)and PMC meiosis I(1000)of hybrid Guang-lu-ai4/O.ala (a)one stainable pollen grain (arrow)and typical abortive pollen grains:(b)diakinesis I with 361:(e)diakinesis I with 211+321.arrow showing bivalents:(d)metaphase I with IIV+5II+221.arrow showing quadrivalents:(e)metaphave I with 3III+311+211.arrow showing trivalents:(f)metaphase I with chromosome straggling (arrow):(g)anaphase I with laggards(arrow):(h)anaphase I with precocious migration of univalents(arrow):(1)anaphase I with imbalanced chromovomes in two poles.(ana- phasve I with multivalent bridge (arrow).(k)telophave I with chromatin masses:(1)telophase I with abnormal spindle orientation:(m)a dyad with ab. normal nuclei:(n)abnormal cytokinesis and spindle orientation:(o)a dyad with abnormal nuclei:(p)triad. Biology of plant reproduction 19