Light and electron microscopy of a distinctive VA mycorrhiza in mature sporophytes
of Ophioglossum reticulatum.
To analyze the concentration of lead in sporophytes
, 50 megaspores were placed in each glass vial (4.5 x 10 cm) with 30 mL of Meyer's solution, prepared in the same way as in Experiment I.
The physiological resilience of fern sporophytes
This success appears to be due primarily to the moist temperate oceanic climate and relatively low competition from other plants, conditions which favor both gametophyte and sporophyte
generations of Equisetum (Page, 1985).
Growth was measures with an ocular caliper on a Zeiss Oberkochen microscope, obtaining photographs of the initial gametophytes and sporophytes
with a Zeiss camera.
Morphological differences in the sporophytes
such as monomorphic and dimorphic fronds and size of spores, seemingly share a similar pattern of germination and development prothallial, and gametophytes of Blechnum are not sufficiently known to provide information for an adequate infrageneric classification (Table 2).
Alginate is the functional analog of agar and pectin in kelps, and oligomeric degradation products of alginate rich in [alpha]-1,4-L-guluronic acid have been shown to elicit an oxidative burst in kelp sporophytes
(Kupper et al., 2001, 2002).
can form sporophytes
on the PVC plates used in commercial abalone farms.
of this species were recently discovered growing with the gametophyte by Paul G.
Spontaneous doubling of the chromosome complement in monoploid sporophytes
Irradiance levels of 0.4 mol photons[multiplied by][m.sup.-2][multiplied by][d.sup.-1] and 0.7 mol photons[multiplied by]m.sup.-2][multiplied by][d.sup.-1] represent the lower limits of irradiance needed for gametogenesis and growth of Macrocystis sporophytes
under ideal temperature and nutrient stress conditions.
We suppose that observations can be made on clonal replicates of haploid meiotic progeny derived from diploid sporophytes
. If the observation on the rth clone (r = 1, 2, .
This is because growth and survivorship of juvenile plants (gametophytes and young sporophytes
) depend on favorable conditions of nutrients and light, which frequently reach critically low levels in giant kelp forests during summer and early fall (especially under the canopy of adult plants), causing high mortality of juvenile kelp plants (Dean and Jacobson 1984, 1986).
2): The mature diploid sporophyte
produces haploid spores after meiosis; the spores germinate in a free-living, haploid and potentially bisexual gametophyte, and finally, the gametophyte produces the sex organs, and after fertilization the new sporophyte
grows, via embryonary development, from the zygotic cell (Prada 2004); whereas female gametophytes of seed plants are nutritionally dependent on the sporophytes
(Yadegari & Drews 2004).