75 research outputs found
A herbĂĄriumrĂłl (gondolatok Ă©s jĂłtanĂĄcsok)
A növĂ©nygyƱjtemĂ©ny (herbĂĄrium) kĂ©szĂtĂ©s â gyƱjtĂ©s, preparĂĄlĂĄs, cĂ©dulĂĄzĂĄs â mĂșzeumok, tudomĂĄnyos intĂ©zetek, esetleg iskolĂĄk Ă©s gyƱjtĆszenvedĂ©lytĆl fƱtött magĂĄnosok szĂĄmĂĄra vĂĄlhat cĂ©llĂĄ. Ez rĂ©szint â a fenti mottĂł szellemĂ©ben â a gyƱjtemĂ©ny-kĂ©szĂtĂ©sĂ©rt magĂĄĂ©rt törÂtĂ©nik. MĂĄsrĂ©szt azonban azĂ©rt, mert a szentencia, hogy ânövĂ©nyismeret nĂ©lkĂŒl nincs botanikaâ ma is Ă©rvĂ©nyes, Ă©s kĂ©tsĂ©gtelen, hogy a növĂ©nyek megismerĂ©sĂ©nek legbiztosabb Ă©s legegyszeÂrƱbb mĂłdja herbĂĄrium kĂ©szĂtĂ©se Ă©s tanulmĂĄnyozĂĄsa. Emellett a terepen dolgozĂł botanikus â bĂĄrmilyen jĂł növĂ©nyismerĆnek is tartja magĂĄt â mindig talĂĄlkozik olyan növĂ©nyekkel, meÂlyeket csak alapos vizsgĂĄlat utĂĄn tud azonosĂtani, kĂ©nytelen is âgyƱjteniâ kĂ©sĆbbi vizsgĂĄlat cĂ©ljĂĄra.</jats:p
Effects of TemperatureâClimate Patterns on the Production of Some Competitive Species on Grounds of Modelling
Climate change has serious effects on the setting
up and the operation of natural ecosystems. Small increase
in temperature could cause rise in the amount of some
species or potential disappearance of others. During our
researches, the dispersion of the species and biomass
production of a theoretical ecosystem were examined on
the effect of the temperatureâclimate change. The answers
of the ecosystems which are given to the climate change
could be described by means of global climate modelling
and dynamic vegetation models. The examination of the
operation of the ecosystems is only possible in huge centres
on supercomputers because of the number and the
complexity of the calculation. The number of the calculation
could be decreased to the level of a PC by considering
the temperature and the reproduction during modelling a
theoretical ecosystem, and several important theoretical
questions could be answered
A balatonvĂz tulajdonsĂĄgainak vizsgĂĄlata algaĂ©lettani kĂsĂ©rletekkel
Chlorella vulgaris Beyer, tenyĂ©szkĂsĂ©rletekkel megĂĄllapĂtottuk, hogy a
balatonvĂz alkalmas tĂĄpoldat alga tömegtĂ©nyĂ©sztĂ©shez, ha a benne kis mennyisĂ©gben
levĆ foszfĂĄtot Ă©s nitrĂĄtot pĂłtoljuk, de mĂ©g jobb eredmĂ©nyt kapunk,
ha az algĂĄk szĂĄmĂĄra legjobbnak talĂĄlt szintetikus tĂĄpoldatunk sĂłit teljes egĂ©szĂŒkben
feloldjuk benne. Tömegtenyészet esetén 3-5% széndioxidot tartalmazó
levegĆ ĂĄtbuborĂ©koltatĂĄsa a siker elengedhetetlen feltĂ©tele.
A tenyĂ©szkĂsĂ©rletekkel szemben megĂĄllapĂthatjuk, hogy az ott minimumfaktorkĂ©nt
jelentkezĆ N Ă©s P adagolĂĄsĂĄval a Chlorella fotoszintĂ©zise nem fokozhatĂł mĂ©g Ă©heztetett sejtek esetĂ©ben sem. Ez arra utal, hogy a Balatonban a
N Ă©s P pillanatnyilag mindig elegendĆ mennyisĂ©gben ĂĄll a fitoplankton rendelkezĂ©sĂ©re.
Ha a balatonvĂz hidrogĂ©n-ion koncentrĂĄciĂłjĂĄt növeljĂŒk, valĂłszĂnƱleg
a hozzĂĄfĂ©rhetĆ szĂ©ndioxid arĂĄnyĂĄnak növekedĂ©se következtĂ©ben a Chlorella
szuszpenziĂł fotoszintĂ©zis-intenzitĂĄsa lĂ©nyegesen nĆ.
MĂ©rĂ©sekkel, szĂĄmĂtĂĄssal Ă©s biolĂłgiai teszttel (csak szabad szĂ©ndioxidot
hasznosĂtĂł lombosmoha asszimilĂĄltatĂĄsĂĄval) egyarĂĄnt arra az eredmĂ©nyre
jutottunk, hogy a Balaton vizĂ©ben legalĂĄbb 0,2-0,4 mg/l COâ van. EredmĂ©nyeink
szerint az a közismert tĂ©ny, hogy a Balatonban Ă©lĆ fitoplankton
biomasszĂĄja arĂĄnylag kevĂ©s, rĂ©szben a benne jelenlevĆ hozzĂĄfĂ©rhetĆ COâ kis
mennyiségével magyaråzható, ami a szénforgalom fontossågåra utal a Balaton
Ă©s a hozzĂĄ hasonlĂł lĂșgos kĂ©mhatĂĄsĂș, mĂ©szben dĂșs tavak esetĂ©ben
Photosynthetic experiments with unicellular algae of different photosynthetic type
Photosynthetic curves of four algal strains (7K Chlorella vulgaris Beyer.,
172 Kirchneriella contorta (Schmidle) Bohlin, 953 Coelastrum microvorum
NĂ€g., 3153 Chlorocloster terrestris Pascher.) investigated in a 3 mM
KOHâKâCOââKHCOâ buffer system of different COâ-deficiency by the usual
Warburg method are discussed in this paper. On the basis of these experiments
three photosynthetic types can be distinguished.
In the first type only free carbon dioxide is utilized (Chlorella vulgaris),
and photosynthesis decreases gradually parallel with the diminution of C02
content. There is no photosynthesis at high pH values and at a surplus of
carbonate ions.
The strain belonging to the second type can utilize both free carbon dioxide
and hydrocarbonate ions, but its rate of photosynthesis becomes slower in a
more alkaline carbonate-containing medium (Kirchneriella).
The algae belonging to the third type can photosynthesize, after a
certain lag-period, most vigorously in a solution containing hydro carbonates
and a surplus of carbonates. Their photosynthesis in solutions containing free carbon dioxide, though starting just at the beginning of illumination,
is slower than in buffers containing either hydrocarbonates or carbonates
(Coelastrum and Chlorocloster).
The experiments presented seem to support the hypothesis that the
strains exhibiting a greater photosynthetic activity in solutions where
carbonate ions predominate over hydrocarbonate ions are able to utilize the
carbonate ions too. It is still undecided, whether the differences in photosynthetic
rates in various buffer systems depend on the availability of carbon
sources or on hydrogen ion concentration.
The great pH tolerance in alkaline range of the strains investigated
may perhaps be brought into connection with the chemical properties of
their natural habitats.
It seems to be an important assumption from the hydrobiological point
of view that the ability of using hydrocarbonate (or carbonate) ions by
planktonic algae is the result of a âtrainingâ taking place in a certain space
of time. Thus, the main purpose of physiological research, when dealing with
the ecology of photosynthesis in planktonic algae, should be to study the aptitude
for this adaptation in the different species
Apparent photosynthesis of Potamogeton perfoliatus L. in different depths of Lake Balaton
Experiments were made in the apparent photosynthesis of Potamogeton
perfoliatus L. The results may be summed up as- follows:
1. For photosynthetic experiments of short duration (only few hours)
isolated leaves are more suitable than the apical portions of shoot.
2. As the calculations made on a dry matter, leaf surface or chlorophyll
content basis show, the photosynthetic rate of the leaves of different plant
specimens collected from natural habitats are very incongruous. Leaves of
the same plant gave good and comparable results. The effect of various light
intensities in different depths of water can be correctly measured by the
relative measurement method of Meyer and co-workers (1941, 1943).
3. According to these studies, the photosynthetic activity of higher
aquatic plants is never inhibited by lack of light on clear summer days, even
if the water is very turbid.
4. Inhibition due to oversaturated light can be studied in the uppermost
layers of optical clear water.
5. Compensation point of photosynthesis and of respiration can not
develop in summer days in the shallow water of Lake Balaton
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