Photosynthetic response to light and temperature was modeled using data from a small red alder (Alnus rubra B. ) community growing in a controlled environment chamber linked to the computer. This new system controls air temperature, root temperature, and vapor pressure over a wide range, and both light intensity and...
Manganese has been known to be essential for photosynthesis
for almost 30 years. Subsequent experimentation
indicated a definite function for manganese in oxygen evolution.
However, the mode of action of manganese and
further localization of its site of action have not been
determined.
Ten years ago it was demonstrated that...
Two light sensitive mutants of the green alga Scenedesmus obliquus strain D₃ have been characterized. The photodynamic nature of their sensitivity has been established, the subchloroplast site of photodamage has been investigated, and their noncarotenogenic character has been verified. The two mutants possess several similarities, although mutant L. S. -41...
A new photosystem-II mutant of the green alga Scenedesmus
obliquus D₃, strain PS-28, has been shown to lack a-tocopherol
(vitamin E). The photosynthetic activity of dark grown samples of
PS-28 is about 20% of the wild-type control. Culturing the mutant
at low light intentisites (10⁴ ergs/sec-cm ²) stimulates photosynthetic
activity...
Because the life processes of the plant are related in a complex
way to the balance between the water demand of the atmosphere and
the water availability to the plant root, an exploration of the dynamic
status of water in the plant is very important. The stomata constitute
the main...
Partial reactions of photosynthesis were examined in the wild
type strain and six photosynthetic mutants (8, 11, 26, 40, 50, a') of
Scenedesmus obliquus, strain D₃. A reproducible procedure for the
isolation of active chloroplast fragments from Scenedesmus was
developed. Several chloroplast reactions were examined, as well
as two in...
Adventitious root formation can be inhibited in stem cuttings
of Pisum sativum L. (pea), an easy-to-root species, if the apical
and lateral buds are removed. Application of exogenous auxin to
the apical stump can replace the rooting stimulus produced by the
buds. Root number was reduced by 50 to 100%...
Many investigators have suggested that current photosynthate
supply can limit adventitious root formation on leafy cuttings.
Accordingly, studies were undertaken to determine the effects of
altering photosynthesis and carbohydrate levels on adventitious root
formation by leafy cuttings of a number of different species.
Pea cuttings rooted at high CO₂ (1800...
Two physiological factors are of major importance to tree and stand growth: (1) the photosynthetic rate of foliage and (2) the amount of foliage. If carbohydrate allocation patterns remain constant, stand growth should be related directly to total canopy photosynthesis. From a literature analysis I assess methods of relating photosynthetic...
The effects of ultraviolet (UV) irradiation on photosynthesis and
various partial reactions involving the individual photoreactions of
photosynthesis were examined. These reactions included photo-reduction in adapted green algae, Hill reaction, cyclic photophosphorylation,
the 520 nm absorbance change and variable-yield fluorescence.
The reactions were measured in spinach chloroplasts and
isolated chloroplasts...
The photosynthetic activities, the pigmentation and the chloroplast
membrane polypeptides of several mutants of the green alga, Scenedesmus
obliquus, with complete or limited deficiencies in the light-harvesting
complex of photosystem II are characterized and compared to those of the
normal phenotype.. The principal phenotype examined in this study, K0 -9,...
Our view of phytoplankton has historically revolved around their inability to
control their location in space. The term phytoplankton itself underscores this
particular difference between phytoplankton and their sessile terrestrial counterparts.
Yet there are other differences between land plants and the phytoplankton that are
perhaps equally important, beyond this sessile-planktonic...
Remote sensing offers the potential for monitoring photosynthesis over large temporal and spatial scales. The purpose of this thesis is to provide information that
will help to develop methods to predict photosynthesis from the light reflected by
canopies. The studies focused on a simple model of canopy photosynthetic potential:
Acanopy...
Many ecological systems follow a seasonal cycle affecting primary production,carbon flux, and vegetative gas emissions. The seasonal variation of ecological systems are both affected by and have effects upon climatic factors. A quantitative estimate of the seasonal variation of vegetation is required to characterize ecological systems and their interaction with...
A steady-state model designed especially for analysis of gas exchange studies of terrestrial net photosynthesis is discussed. The model expresses net photosynthesis as a function of light, temperature, CO₂ concentration, stomatal resistance, and other factors. The parameters of the model are
estimated from data by nonlinear least-squares. The data set...
Water treatments were applied to young ponderosa pine trees in the Eastern Cascades, Oregon during the 2003 growing season, and shade treatments were applied during the 2003 and 2004 growing seasons to understand how photosynthesis and soil respiration, particularly the root/rhizosphere fraction (R[subscript rrh]), would respond to increased moisture availability...