نتایج جستجو برای: pollen morphology
تعداد نتایج: 165631 فیلتر نتایج به سال:
The male gametophytes of gymnosperms are characterized by the diversities in pollen morphology, cellular composition and pattern of cell division, pollen tube morphology, sperm delivery, growth pattern through the ovule and nucellus, and pollen tube wall composition both within and among the four living orders, i.e., Cycadales, Ginkgoales, Coniferales, and Gnetales. At dehiscence, gymnosperm po...
دانه گرده چهار گونه از آدونیس های ایران شامل: Adonis wolgensis Stev. ، Adonis aestivalis L. ، Adonis dentata Del. و Adonis flammea Jacq. توسط دستگاه میکروسکوپ الکترونی نگاره (SEM)، مورد مطالعه و بررسی قرار گرفت. در طی این مطالعه 10 خصوصیت مختلف گرده شناسی سنجیده و اندازهگیری شدند. تمامی دانههای گرده بررسی شده سه شیاره (Tricolpate) میباشند، تزئینات دیواره خارجی دانه گرده(Exin) در دو تی...
to analyze their intrinsic mechanisms. Easy observation of chlorophyll facilitates the study of the underlying mechanisms in chloroplasts, but not in other plastid types. Here, we constructed a transgenic plant enabling visualization of plastids in pollen grains. Combination of a plastid-targeted fl uorescent protein with a pollen-specifi c promoter allowed us to observe the precise number, siz...
Larvae and adults of certain species of predator lady beetles feed on pollen, guaranteeing their survival, and at times, reproduction in the absence of preferred prey. Palynology, therefore, may contribute in the investigation of botanical families visited by these predators in order to obtain this floral resource. There are records of the visitation of Apiaceae flowers by Coleomegilla maculata...
Intraspecific variation in pollen deposition and number of pollen tubes per style is rarely quantified, but is essential for assessing the occurrence of pollen limitation and pollen competition and their evolutionary implications. Moreover, pollen deposition, pollen tube growth, and the fate of fertilized ovules are rarely distinguished in field studies. Here we present such a study in eight na...
چکیده ندارد.
BACKGROUND The Saururaceae, a very small family of Piperales comprising only six species in four genera, have a relatively scanty fossil record outside of Europe. The phylogenetic relationships of the four genera to each other are resolved, with the type genus Saururus occurring in both eastern North America and East Asia. No extant species occurs in western Eurasia. The most exceptional find s...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید