Pollen Ultrastructure of the Biovulate Euphorbiaceae

نویسندگان

  • Michael G. Simpson
  • Geoffrey A. Levin
  • MICHAEL G. SIMPSON
چکیده

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected].. Pollen ultrastructure of the biovulate Euphorbiaceae, including the subfamilies Phyllanthoideae and Oldfieldioideae, was investigated with light, scanning electron, and transmission electron microscopy. Pollen of Phyllanthoideae, represented by 12 species in nine genera, was prolate to oblate, almost always 3-colporate, rarely 3-porate or pantoporate, and mostly with reticulate, rarely baculate, echinate, or scabrate, sculpturing. The ektexine showed little variation in ultrastructure; almost without exception it was tectate-columellate with a homogeneous foot layer, columellae continuous with both the tectum and the foot layer, and a perforate, homogeneous tectum. The only major exception was Amanoa guianensis, which was intectate and baculate as the result of the evolutionary loss of the tectum. Pollen of Oldfiel-dioideae, in which we studied 28 species from 25 genera, and obtained data from the literature for two of the three remaining genera in the subfamily, was globose to oblate, with four or more, rarely only three, apertures that were either equatorial and brevicolporate to porate or pantoporate, and with echinate, rarely scabrate, sculpturing. The ektexine showed considerable variation in ultrastructure. The most widespread structural type consisted of a foot layer that is either thin and irregular or absent, an interstitium composed of irregular to columellate exine deposits that are discontinuous from the foot layer, if present, and a tectum composed of laterally appressed baculate elements that delimit fine microperforations. A second common structural type differed in having a relatively thick, homogeneous foot layer and thin, granular to tabular, microperforate tectum. Isolated genera have a reduced interstitium and/or a homogeneous tectum or show a reversal to a tectate-columellate architecture. Variation in aperture morphology, sculpturing, and exine ultrastructure is phylogenetically significant in the Oldfieldioideae.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Systematic Anatomy of Euphorbiaceae Subfamily Oldfieldioideae I. Overview

The biovulate subfamily Oldfieldioideae of Euphorbiaceae, characterized by spiny pollen, is an otherwise apparently diverse assemblage of mostly Southern Hemisphere trees and shrubs that traditionally have been allied with genera of Phyllanthoideae and Porantheroideae sensu Pax and Hoffmann. Although fairly diverse anatomically, the following structures characterize the subfamily with only a fe...

متن کامل

Phylogenetic Implications of Pollen Ultrastructure in the Oldfieldioideae (Euphorbiaceae) Author(s):

The pollen structure of members of Euphorbiaceae subfamilies Oldfieldioideae and Phyllanthoideae was studied using scanning and transmission electron microscopy in order to assess taxonomic relationships. We identified 10 palynological characters that appear to have systematic significance. We also identified 37 characters of vegetative morphology and anatomy, mostly based on data obtained by H...

متن کامل

Phylogenetic Relationships of Didymocistus and Hymenocardia ( Euphorbiaceae )

The genus Hymenocardia has been placed either in Euphorbiaceae subfamily Phyllanthoideae or in its own family and then associated with the Urticales, particularly the Ulmaceae. However, the pollen exine wall of Hymenocardia lacks the microchanneled tectum, granular interstitium, and thin foot-layer of the Urticales. Hymenocardia instead has many palynological features found in the Phyllanthoide...

متن کامل

بررسی ساختار اندام‌های رویشی و تکوین اندام‌های زایشی بادیان رومی (.Pimpinella anisum L)

Pimpinella anisum L. belongs to Apiaceae family. The samples of vegetative and reproductive organs at different stages of development were gathered and investigated by cell-histology methods. The investigation of the anatomical structure of vegetative organs showed that the secretory ducts are arranged between the parenchymal tissues of the leaf. Section of flower buds revealed that anthers had...

متن کامل

Pollen record and paleoenvironment of a 4210 years B.P.old sediment in the Bay of Guanabara, Rio de Janeiro, Brazil.

Pollen analysis of a sediment sample obtained at 222 cm from the top of a drilling core collected in the Bay of Guanabara, Rio de Janeiro, was used as a tool to obtain more knowledge about pre-historical human living and environment. 14C datation revealed the age of 4210 years B.P. Most frequent pollen grains came from plants like Alchornea (Euphorbiaceae), Celtis (Ulmaceae), Lecythidaceae, Mel...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2010