The Preliminary Study On Reproductive Biology Of Iris Sanguinea Donnex Horn

This paper studies blossom biology,pollination biology,the formation of reproductive organ and germ cell,fertilization and regulation of embryogenesis of Iris sanguinea by means of the floral syndrome,the flowering dynamics,pollen activity and stigma receptivity,out-crossing index,pollen-ovule ratio,fruit set and seed-set,pollinators and embryology.The test results are as follows:1、The Iris sanguinea population in Harbin started to bloom in early June,and reach full bloom in the middle of June,lasting about one week.The blooming came into the end in late June.The flowering season of the population was about20days and the life span of a single flower was about2days.The extrorse anther was closed to the lateral side of the petaloid style.The distance between the anther and the stigma was about lmm,and the relative position between them was constant during the whole blooming period.The flowering of Iris sanguinea was largely influenced by climatic factors.2、The highest pollen activity was in2hours after blooming and the pollen activity falled to2.8%at five p.m. of next day of blooming.The stigma receptivity was strongest in2-4hours after anther dehiscence and sustainable until next day of blooming.The optimum artificial pollination time of Iris sanguinea was at nine a.m. of blooming day.3、The out-crossing index (OCI) was4,and the ratio between pollen and ovule (P/O) was276.26,which indicated a breeding system of out-crossing,part self-compatibility,and insect pollinator-dependence.Artificial cross-pollination improved reproductive success and sexual reproduction was mainly influenced by less pollinators in nature.4、Iris sanguinea belonged to typical entomophilous flower,the highly specialized floral structure was adapted to the behavior of the pollinators,Apis mellifera etc.The visiting frequency of Apis mellifera was0.027each flower in one minute and the ratio of visiting the same flower was about3.2%.The average visiting time of each flower was (8.6±2.5)s.5、Maintain the population stability by promoting out-crossing,improving seed setting rate and strong rhizomatous growth behaviour.6、The tapetum of Iris sanguinea was glandular.Cytokinesis in the microsporocyte meiosis was of the continuous type.The microspore tetrads were bilateral or tetrahedral.7、Style was open type.Pistil composed by three carpels;axial placenta.Ovules were anatropous,bitegminous and crassinucellate.The megaspore tetrads were linear,T-type or bilateral,but only the megaspore near the chalazal end remained.The formation of embryo sac was Polygonum type.8、The mature period of male gametophyte were about two days earlier than female gametophyte. 9、After artificial pollination22-24hours,pollen tube got into one of synergids.The duration of zygote dormancy was about5-6days and the fusion of nucleoluses was the type of the premitotic gametogamy.The duration of the primary endosperm nucleus dormancy was4-6hours and the development of endosperm was nuclear type.