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K. Redford M. D. Berliner J. E. Gates R. W. Fisher B. F. Matthews 《Plant Cell, Tissue and Organ Culture》1987,10(3):187-196
We have developed a method for producing protoplasts from the heterosporous water fern Azolla using a combination of Cellulysin (4.0%) and Pectolyase (0.025%) in 0.6 M mannitol containing 6 mM CaCl2 2H2O. These protoplasts regenerate new cell walls within 48 hours when cultured on modified Gamborg B-5 medium. 相似文献
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Bicarbonate enhances synchronous division of the giant nuclei of sporophytes in<Emphasis Type="Italic"> Bryopsis plumosa</Emphasis> 总被引:1,自引:0,他引:1
A mature sporophyte of Bryopsis plumosa (Hudson) C. Agardh forms a huge number of zoospores in its cell continuum. Zoospore formation starts with the division of
a single giant nucleus and subsequent repeated mitosis. We found that an elevation of photosynthetic activity triggered the
division of a mature giant nucleus. Transfer to short-day conditions was not necessary. Giant nuclei did not divide in darkness
or in the presence of 1 μM DCMU. Giant nuclei of as many as 90% of sporophtyes started to divide following the addition of
5 mM NaHCO3 to the growth medium under continuous white light (6–12 W m−2). Frequency of nuclear division increased with increased light intensity. By combining those parameters that promoted the
division of giant nuclei, we developed the "two-step culture method" which is composed of preliminary and main cultures. This
new method guarantees that giant nuclei of more than 90% of all sporophytes synchronously divide between 72 and 96 h after
the transfer to the main culture (continuous white light of 12 W m−2 in PES medium supplemented with 5 mM NaHCO3). 相似文献
3.
Lisa K. Russell Christopher D. Hepburn Catriona L. Hurd Michael D. Stuart 《Biological invasions》2008,10(1):103-115
Very few studies have addressed how the invasive kelp Undaria pinnatifida (Harvey) Suringar spreads beyond initial founding populations in harbours. Surveys of the harbours and accessible areas of
open coast throughout southern New Zealand were conducted to determine how far U. pinnatifida populations had extended since initial incursions. Our findings clearly demonstrate that U. pinnatifida is capable of invading native communities and can establish reproductive populations in locations subjected to significant
and consistent wave action. The extent of spread from source populations differs between harbours in which it has established.
Dispersal is greatest in harbours with long established populations, those where populations have not been strategically managed,
harbours with high water exchange with surrounding coastal waters, and where prevailing currents allow establishment of U. pinnatifida on suitable substrata close to harbour entrances. Dispersal along the open coast is primarily achieved by drifting adult
sporophytes that are washed up in the rocky intertidal zone. Founding populations are most often found in the intertidal zone,
primarily within rockpools. Subtidal transects and observations indicate that U. pinnatifida is well adapted to invade exposed coastlines and can establish within a broad range of niches in wave-exposed areas including
rockpools, the low intertidal, shallow subtidal, Macrocystis pyrifera kelp forests, and in low light areas beyond the vertical extent of large native macroalgae. The current range of U. pinnatifida is much greater than expected and appears to be expanding. Due to its ability to grow in a broad range of environments and
to form dense monospecific stands, U. pinnatifida has the potential to strongly modify almost all rocky subtidal and intertidal communities in temperate locations. 相似文献
4.
At an early stage of growth gametophytes support the sporophytes of ferns. Young sporophytes become independent of gametophytes
when the first leaves develop. Although large fern gametophytes produce multiple archegonia simultaneously, only one sporophyte
is typically established on one gametophyte. The number of sporophytes is believed to be controlled in two possible directions,
from gametophyte to sporophyte or from preceding sporophyte to another sporophyte. To investigate the effects of gametophytes
on their sporophytes, we studied the relationship between organic matter production by gametophytes and the growth of young
sporophytes of Thelypteris palustris. We cut gametophytes in half (CGs) to reduce the gametophytes’ production of matter. There was no significant difference
between the growth of sporophytes on intact gametophytes (IGs) and that on CGs. According to our estimates, based on the rate
of organic matter production, the large gametophyte was able to produce two or more sporophytes. The resources required for
CGs to make similar-sized sporophytes was twice that for IGs. In polyembryony each of the multiple sporophytes was similar
in size to the single sporophytes. Resource limitation does not seem to explain why fern gametophytes establish single sporophytes. 相似文献
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