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infratectum is granular, mostly consisting
of small granules, while the
endexine is uniformly thick and lamellate.
The recently discovered fossil
gnetophytes are a diverse group, recognized
primarily on the basis of their ovulate
cupules, but heterogeneous in respect
to their pollen organs and pollen
morphology. The pollen grains are
mostly asaccate or, rarely, bisaccate
(Preflosella, Dinophyton), with small
ruguloid sacci (Baisianthus) or vestigial
protosaccate structures (Cryptosacciferites).
The germination types are inaperturate,
cryptoporate, monosulcate
and trisulcate. In the majority of forms
the infratectum is granular, consisting of
small granules, large granules, combinations
of various granules, or even columella-like
elements; rarely, the infratectum
is alveolar. The endexine varies
from distinctly lamellate to homogeneous.
Our analysis of pollen grain morphology
and ultrastructure of extant
gnetophytes lends support to phylogenetic
relatedness of extinct forms. Palaeobotanical
data show a striking parallelism
of morphological variations between
gnetophytes and angiosperms.
2010010065
Osmunda regalis L. 孢 子 与 相 似 孢 子
在 形 态 、 发 育 及 外 壁 结 构 上 的 对 比 =
Morphological, developmental and ultrastructural
comparison of Osmunda
regalis L. spores with spore mimics. ( 英
文 ). Moore S E M; Gabarayeva N;
Hemsley A R. Review of Palaeobotany
and Palynology, 2009, 156(1-2): 177-
184 3 图 版 .
A comparison of spores from Osmunda
regalis L. and polystyrene-based
spore mimics has been undertaken in
order to provide insights into the development
and formation of relatively
primitive fern spores. In recent years,
self-assembly experiments have provided
different perspectives on the processes
involved in pollen and spore wall
pattern formation. The spore mimics obtained
from the latest experiments
closely resemble extant spore types and
permit comparison with both immature
and mature spores.
2010010066
Trevesia burckii( 五 加 科 ) 四 分 体 期
孢 壁 的 发 育 II: 自 集 合 作 用 的 更 多 证
据 = Sporoderm development in Trevesia
burckii (Araliaceae): II. Post-tetrad
period: Further evidence for the participation
of self-assembly processes. ( 英
文 ). Gabarayeva N; Grigorjeva V; Rowley
J R; Hemsley A R. Review of Palaeobotany
and Palynology, 2009,
156(1-2): 233-247 6 图 版 .
The developmental events in the periplasmic
space, the cytoplasm of microspores
and in the tapetum of Trevesia
burckii have been traced in detail during
microspore ontogeny from the late tetrad
stage, through the post-tetrad period, to
intine formation (following on from our
study of the tetrad period also published
herein). The data obtained give further
support to our previously proposed hypothesis
regarding self-assembly of a
number of colloidal micellar systems
during exine (and possibly intine) development.
The main structures of the mature
exine are columellae, granules and
tripartite lamellae with central white
lines which evidently form on a base of
cylindrical, spherical and lamellar transitive
micelle mesophases after sporopollenin
accumulation. Further information
provides evidence for the importance of
physico-chemical regularities in pollen
wall development.
2010010067
通 过 扫 描 透 射 X 射 线 显 微 镜
(STXM) 研 究 现 代 和 化 石 孢 壁 的 外
壁 结 构 及 化 学 成 分 = Ultrastructural
and chemical study of modern and fossil
sporoderms by Scanning Transmission
X-ray Microscopy (STXM). ( 英 文 ).
Bernard S; Benzerara K; Beyssac O;
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