FURTHER OBSERVATION ON TAPETUM AND POLLEN DEVELOPMENT IN WATERMELON Observation on the microspore abortion of photoperiod- sensitive male sterilemiliet (Setaria italica) 683 Microsporogenesis and Male Gametophyte Development of Juniperus rigida Identification of a New Cytoplasmic Male Sterility Type NRO4270A in Brassica napus Comparative study on meiotic behavior and pollen development of  medicinal plants Liriope spicata var. prolifera and L. spicata Investigation on meiosis of the rare and endangered plant——Calycanthus chinensis Studies on Microsporogenesis and Development of Male Gametophytes in Endangered Species Glyptostrobus pensilis STUDIES ON THE MICROSPOROGENESIS AND THE FORMATION OF THE MALE GAMETOPHYTE IN PLATYCLADUS ORIENTALIS