Gary, Sorry to be completely unintellectual - but Lichens are SO COOL! Trying to narrow down a paper topic for Botany class- one idea is gap dynamics in the NYBG forest and the other is Lichens....I think I'm going for the lichens. I have amazing lichen photos from Maine and Arizona, mostly on rocks (because rocks are SO COOL too....! - I'll try not to use this expression in paper...)
Thanks for your info, Jenny On Mar 12, 5:46 pm, [email protected] wrote: > One interesting hypothesis is that early. Plants were an "inverted lichen", > algae left the aquatic environment with the help of protofungi in a symbiotic > relationship. The fungi provided the protection from dissication and also > served as the interface between the macroscopic algae and soil. Symbiotic > (both ecto and endo symbionts) relationships are probably underestimated in > the functioning of terrestrial ecosystems. > > Gary > Sent via BlackBerry from T-Mobile > > -----Original Message----- > From: Lee Frelich <[email protected]> > > Date: Thu, 12 Mar 2009 11:23:54 > To: <[email protected]> > Subject: [ENTS] Re: Roots? > > Jenny: > > Regarding mycorrhizae, its one of those interesting questions where the > answer is yes and no. With very high soil fertility, trees can survive > and grow without them, and in isolation, they can often grow without > them. However, under most field conditions, and with the competition > from numerous other trees, they are necessary for an individual tree to > survive and grow, as well as for the function of the entire ecosystem. > > Regarding nitrogen fixation--its another case where both answers are > correct. Free living bacteria (Azotobacter and Clostridium, some > blue-green algae, and others) fix a small amount of nitrogen in the > soil. Rhizobium bacteria form a symbiotic relationship with roots, in a > nodule, which can easily be seen if you pull up a clover plant. This > occurs mainly in legumes (locust), but also in some other trees (via > other genera of microorganisms) such as alder, and shrubs such as Myrica > (sweet gale), and Shepherdia (buffaloberry). The presence of nitrogen > fixing plant species can fertilize the soils, thereby increasing the > growth of tree species that cannot form nitrogen fixing nodules. > > Whether the nodule forming microorganisms are considered part of the > tree depends on your point of view. They are halfway between ancient > microorganisms such as certain algae and bacteria that have become > chloroplasts in leaves, and mitochondria in cells of plants and animals > (which are clearly part of the organisms, and cannot live by > themselves), and microorganisms that cannot form a symbiotic > relationships with plants at all. Its a continuum, and where you make a > distincion along that continuum depends on the individual > > Lee > > JennyNYC wrote: > > Lee, et. al., > > > I would love to see one of these "rhizotrons". Fascinating. > > > I have questions if anyone can help me out: > > > 1. Are mycorrizae absolutely essential for young tree roots to grow > > and do trees have mycorrizae associations throughout their lives? > > > 2. I'm confused about the exact relationship between the bacteria in > > the soil that fix nitrogen and the tree root itself. I know this is > > a broad and vague question....just wondering it those bacteria are > > considered part of the tree organism? > > > Thanks, > > > Jenny > > > On Mar 12, 8:54 am, Lee Frelich <[email protected]> wrote: > > >> Ed et al.: > > >> We usually measure root biomass by taking soil cores (usually 2-4 inches > >> in dimeter, from 1-3 feet deep, depending on the purpose of the study), > >> and separating the roots so they can be dried and weighed. By taking a > >> number of such samples, we can estimate the biomass of roots per acre in > >> the forest. Roots are also studied in rhizotrons (underground rooms with > >> large windows all around). One can observe the root growth against the > >> windows, study how earthworms move, and how the soil zonation changes > >> over time, etc. The University of Michigan Biological Station and > >> Michigan Tech have rhizotrons that I have visited. There are also mini > >> rhizotrons that can be placed throughout the forest. > > >> Of course, these do not give you an estimate of the roots of one tree. > >> I have seen that done by blasting away the soil with high pressure > >> hoses, so that the root system can be mapped and measured. This is done > >> in a stand that is planned to be clearcut, or perhaps a few trees in an > >> experimental forest, and it only works in ecosystems with shallow soils > >> and/or rooting depths. > > >> Lee > > >> Edward Frank wrote: > > >>> Jenny > > >>> I am sure if there was some practical and non-destructive method of > >>> measuring the roots underground, we would give it a try. Ground > >>> Penetrating > >>> Radar is still a little expensive at the moment. > > >>> Ed > >>> ----- Original Message ----- > >>> From: "Jennynyc" <[email protected]> > >>> To: "ENTSTrees" <[email protected]> > >>> Sent: Wednesday, March 11, 2009 8:06 PM > >>> Subject: [ENTS] Re: Roots? > > >>> Russ, > > >>> Thanks for letting me know about this. > > >>> Jenny > > >>> On Mar 11, 2:27 pm, [email protected] wrote: > > >>>> Jen: > > >>>> No. That type of work is usually done by researchers looking for a > >>>> specific > >>>> piece of information about a tree or group of trees. > > >>>> Russ > >>>> **************Need a job? 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