A gland in male mammalssurrounding the urethra in the region where itleaves the bladder. It releases a fluid con-taining various substances,including en-zymes and an antiagglutinating factor,thatcontribute to the production of semen.Itssize and secretory ...[继续阅读]

    A glandular and vascularswelling of the epidermis of some Annelida(earthworms and leeches),involved in re-production. In the earthworm,it occurs oversegments 32 to 37 and forms the site of at-tachment for segments 9 to 15 of a mate atcopulation. It secret...[继续阅读]

    A theory of apicalorganization and development that distin-guishes two separate tissue zones,the tunicaand the corpus,in the apex of a floweringplant. The tunica is made up of one or moreperipheral layers in which cell division ismostly anticlinal. The co...[继续阅读]

    In some classifications,a kingdomof simple organisms including the bacteria,algae,fungi,and protozoans. It was intro-duced to overcome the difficulties of assign-ing such organisms,which may show bothanimal and plantlike characteristics,to thekingdoms Ani...[继续阅读]

    The mouth cavity,by whichfood is taken into the alimentary canal. Inmammals it is surrounded by the lips andcheeks,which enclose the food while it isbeing chewed by the teeth and tasted by thetongue,which also helps to move the foodback for swallowing. Du...[继续阅读]

    The ripened ovary of a flower that isusually formed following fertilization of theovule. It may consist of the ripened ovary on-ly or include other parts of the flower. Fruitsvary according to the method of seed disper-sal,succulent fruits normally being ...[继续阅读]

    Any member of a large phylumof fungi (Ascomycota) characterized by theirdistinctive reproductive structure,the ascus,in which spores are formed,usually eight innumber. Ascomycetes are subdivided accord-ing to how the asci are borne,to give thehemiascomyce...[继续阅读]

    An elongated flattened fluid-filled sac forming the basic unit of the photo-synthetic membrane system in chloroplastsand photosynthetic bacteria.See chloroplast.在叶绿体和光合细菌中,一种长而扁平的充满液体的小囊,类囊体是形成光合作用膜系统的基本单位。...[继续阅读]

    The final stage in mitosis andmeiosis before cells enter interphase. Duringthis stage chromosomes uncoil and disperse,the nuclear spindle degenerates,and a newnuclear membrane forms. The cytoplasm mayalso divide during this phase.细胞进入间期前的有丝分裂和减数分裂的最后一个阶段...[继续阅读]

    A method of plant growth in which the cellsenlarge and force their way between othercells,causing their disruption. Comparesliding growth,symplastic growth.植物生长的一种方式,细胞增大,用力插入其他细胞间,造成其他细胞的破坏。比较756页slidinggrowth:796页symplastic gro...[继续阅读]