The Gametophyte of Lycopodiella prostrata

2007·2.6 MB·English

by  Dean P Whittier

American
Fern Journal <)7(4):230-236 (2007)
Shorter Notes
—
The Gametophyte As
of Lycopodiella prostrota. an extended study
part of
on mycorrhizal and photosynthetic: gametophytes of the Lycopodiaceae, spores
of Lycopodiella prostrota (Harper) species with an undeserved
Cranfill, a
gametophyte, were The were
cultured. spores obtained from plants collected
VSU
in Cook County, Georgia and a voucher was deposited [Carter #14616).
at
medium
The conditions, techniques, and nutrient used were those of Whittier
and The
Renzaglia (Amer. Fern 95:153-159. system
2005). of classification
J.
followed in this report that of 011gaard (Opera Bot. 92:15:]- 178. 1987).
is
There gametophyte Lycopodium Four
are five types in of the five are
(s.L).
-
mycorrhizal with the following shapes carrot-shaped, disk-shaped, uniaxial
strap-shape, and branched cylindrical. The type, which has been reported
last
more
for Lycopodiella, photosynthetic with a solid, or less cylindrical base
is
topped with photosynthetic lobes. This study was carried out determine
to
if
gametophyte
the of prostrata this type.
L. is
Spore germination was slow. The germination occurred two months
earliest
sowing spores illuminated and one
after in cultures, year, 61 spores out of
at
10,000 (0.6%) had germinated. Spores cultured in the dark for one year did not
germinate; however, spores from these dark cultures remained viable and 142
of them out of 10,000 (1.4%) germinated after moving them into the light for
seven months.
Although spores of the mycorrhizal species of Huperzia and Lycopodium
germinate slowly and low percentages Amer. Fern 88:106-113.
(Whittier,
at
J.
1998), generally believed that Lycopodiella spores germinate rapidly and
is
it
at high percentages (Whittier, Amer. Fern 88:106-113. 1998). This not
is
}.
completely true because spores from some Lycopodiella species germinate
slowly Amer. Fern 88:106-113.
(Whittier,
1998).
J.
Cell divisions in various planes formed a small mass of gametophyte tissue
that remained partially contained by the spore coat. At about six weeks of
growth, the young gametophyte escaped from the spore At time
coat. this
-
a small, dark green, ellipsoidal mass of cells formed the young primary
tubercle (Fig. 1A). Once the main body of the tubercle had a width of 150 \am
or more, the first photosynthetic lobe developed at apical end (Figs. IB, 1C).
its
Further enlargement of the tubercle resulted in a larger apical region where
The
additional photosynthetic: lobes formed. lobes were narrow, and
erect,
strap-shaped with
tapering distal ends.
The
mature gametophytes had more
early
a short, solid, or less cylindrical
base topped with numerous photosynthetic As gametophytes
lobes. the aged,
more and
lobes formed, the previously formed lobes were displaced the
to
Gametophytes ID
sides of the larger base. at this stage are illustrated in Figs.
and
IE.
The
gametangia formed
usually the junction of the photosynthetic lobe
at
and the gametophyte base. Both archegonia and antheridia developed on the
SHORTER NOTES
231
Gametophytes
Fig. of Lycopodiella prostrata. A. Primary tubercle. B-C. Primary tubercles
1.
mo
young
(arrows) with photosynthetic lobes (ca. 2 old). D. Oblique view of early mature
mo
mo Two
gametophyte Apical view gametophyte
(ca. 5 old). E. of (ca. 7 old). F. archegonia with
Two -
short necks. G. antheridia one with view of opercular cell (arrow). H. Large gametophyte
mm
(ca. 18 mo old) with young sporophyte (arrow). Bars = 100 Jim for Figs. A-C & F-G, for
1
mm
D-E, and
Figs. 2 for Fig. H.
VOLUME NUMBER
AMERICAN FERN
JOURNAL:
97
232 4 (2007)
young mature gametophytes. The archegonia had short necks made up of two
The
of neck cells exposed above the gametophyte surface (Fig. IF). length
tiers
of the archegonial neck was about 70 |im long. The length from the tip of the
was determined with
neck base of egg about 110 |im as optical sections.
to
Each antheridium had one opercular the antheridial jacket the
cell in at
showed gamete masses
gametophyte surface (Fig. 1G). Optical sections the of
the antheridia be essentially spherical with diameters of about 70 \im.
to
The young gametophytes with both antheridia and archegonia
small,
medium
continued grow on the nutrient without undergoing sexual
to
With medium-sized gametophytes took on pincush-
reproduction. age these a
more pincushion-
ion shape (Fig. ID, IE). After a year or in culture, large
The gametophytes
shaped gametophytes formed. solid basal portions of these
numerous
were obscured by the photosynthetic lobes (Fig. 1H).
was added
Mature gametophytes were capable of fertilization water to the
if
gametophytes growing separate cultures produced 24
cultures. Fifty older in
The which were
with microphylls,
sporophytes flooding water.
after first
were two weeks
larger than the photosynthetic lobes, evident after flooding.
Within three months the young sporophytes became well established with
numerous microphylls growing above the photosynthetic lobes (Fig. 1H).
The development of the primary tubercle typical for Lycopodiella
is
known
gametophytes and oblong shape from other species
the ellipsoidal or
is
A
& Amer. Fern 95:153-159. growth from the top
(Whittier Renzaglia, 2005).
J.
which was Lycopodiella
of the tubercle, the intermediate shaft, reported for
New
48:253-
gametophytes growing on (Holloway, Trans. Zealand Inst.
soil
Amer. 66:1156-1163. does not develop in
303. 1916; Bruce, Bot. 1979), L.
J.
growth Lycopodiella
prostrata under these conditions. appears that the of
It
gametophytes well-illuminated cultures prevents the development of the
in
intermediate shaft (Whittier & Renzaglia, Amer. Fern 95:153-159. 2005).
J.
Photosynthetic lobes develop from the top of the tubercle in L. prostrata as
was observed with the gametophyte of Lycopodiella lateralis (R.Br.) B. 011g.
The
& Amer. Fern 95:153-159. formation of the
(Whittier Renzaglia, 2005).
}.
many
from
pincushion-shaped gametophyte with green lobes arising a solid
(Wagner & North America 2:18-
Lycopodiella Flora
base typical for Beitel,
is
The young pincushion-shaped gametophytes with photosynthetic
37. 1993).
lobes arising from the apex and sides of the solid base appear to have a radial
symmetry The symmetry pincushion-shaped
ID, of the larger
(Figs. IE).
was Lycopodiella
gametophytes 1H) appears dorsiventral as reported for
(Fig.
The
carolinianum by Bruce (Amer. 66:1156-1163. 1979). long strap-
Bot.
J.
gametophytes previously
shaped have been described Lycopodiella
lobes for
(Wh
159. 2005).
photosyn-
Both gametangia form on these gametophytes the base of the
at
have
Descriptions of Lycopodiella archegonia indicate that they
thetic lobes.
Wagner & Ann. Mo.
necks Amer. 63:919-924. 1976; Beitel,
short (Bruce, Bot.
J.
Bot. Gard. 79:676-686. 1992). The antheridia are smaller than those reported
& Amer.
Huperzia Pintaud, Braggins,
the species of (Whittier,
for terrestrial
much Lycopodium
Fern 95:22-29. 2005) and smaller than those of (Bruce,
J.
—
SHORTER NOTES
2 3 3
Amer. 66:1138-1150. Canad. 55:563-567.
Bot. 1976; Whittier, Bot. 1977).
J. J.
The &
gametangia of Lycopodiella appressa (F.Lloyd Under.) Cranfill and
L.
Lycopodiella cernua Pichi-Serm. have essentially the same sizes as those
(L.)
The
gametangia
of L. prostrata. of L. prostrata are typical for Lycopodiella.
The development of the other types of gametophytes of the Lycopodiaceae
is
from found The mature gametophyte
quite different that in Lycopodiella. of
Phylloglossum photosynthetic but starts out as a subterranean, mycorrhi-
is
it
zal gametophyte that is negatively gravitropic. After its exposure to light at the
soil surface becomes a green, bilaterally symmetrical, tuberous gametophyte
it
&
lacking photosynthetic lobes (Whittier Braggins, Amer. Bot. 87:920-924.
J.
2000).
The
remaining gametophytes Lycopodiaceae
of the are subterranean,
mycorrhizal, and nonphotosynthetic. Their development un-
initiated
is
derground by the dark germination of their spores and requires a mycorrhizal
association for continued growth. Early growth forms a solid, teardrop-shaped
gametophyte that gives rise to the four other gametophyte shapes found in the
Lycopodiaceae. Larger teardrop-shaped gametophytes develop meristems
ring
that form the radially symmetrical disk- and carrot-shaped gametophytes of
Lycopodium
(Whittier, Canad. Bot. 55:563-567. 1977; Whittier, Bot. Gaz.
J.
142:519-524.
1981).
The
gametophyte
uniaxial, dorsiventral, strap-shaped of the
terrestrial
Huperzia The
species lacks a ring meristem. meristem arises from a portion
of the apical region of a larger teardrop-shaped gametophyte (Bruchmann,
Flora 101:220-267. This meristem occurs subterminal groove
1910). in a
overarched by young dorsal tissue on these strap-shaped gametophytes. With
the epiphytic Huperzia species, the teardrop-shaped gametophyte enlarges
and grows into the branched, cylindrical, mycorrhizal gametophyte (Whittier
unpublished).
The
gametophyte and development
of prostrata has the typical structure
L.
of Lycopodiella gametophytes; thus different from the other gametophyte
it is
types of the Lycopodiaceae. Dean Whittier, Department of Biological
P.
TN
Sciences, Box 1634, Vanderbilt University, Nashville, 37235-1634, and
Richard Carter, Department of Biology, Valdosta State University, Valdosta,
GA
31698-0015.
New
Three Flavonoid Kaempferol
Glycosides, 3-0-(caffeoylrhamnoside),
Apigenin and from
4'-0-(caffeoylglucoside) 4-0-(feruloylgliicoside)
—
Dryopteris Ten flavonol O-glycosides (based on kaempferol and
villarii.
quercetin), two flavanone O-glycosides (based on naringenin and eriodictyol)
and and
three C-glycosylflavones vitexin, vitexin 7-O-glucoside orientin)
(
have previously been by Hiraoka (Biochem. 171-175.
identified Syst. Ecol.
6:
1978) in eighteen Dryopteris species whereas 3-desoxyanthocyanins have been
found Kuntze by Harborne
in red sori of Dryopteris erythrosora
(Eat.)
(Phytochemistry 589-600. 1966). In addition kaempferol 7-0-(6"-succinyl-
5: