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The effect of soil moisture suction and soil temperature on transpiration, photosynthesis and respiration in Monterey pine (Pinus radiata D. Don)

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Title The effect of soil moisture suction and soil temperature on transpiration, photosynthesis and respiration in Monterey pine (Pinus radiata D. Don)
Names Babalola, Olaoluwa (creator)
Youngberg, C. T. (advisor)
Date Issued 1967-04-24 (iso8601)
Note Graduation date: 1967
Abstract A special apparatus was developed in which the soil moisture
levels of several soil cells could be maintained independently by
various osmotic solutions at a selected temperature. The effect of
four soil moisture suctions and four soil temperatures on the rates
of transpiration, photosynthesis and respiration of monterey pine
seedlings was studied. Transpiration was determined by a constant
water level device which recorded the total amount of water used by
the plant. Leaf resistances to CO₂ and water vapour were calculated.
In general, the rates of photosynthesis, respiration and
transpiration decreased with increasing soil moisture suction.
Photosynthesis and transpiration decreased sharply from 0.35 bars
to 0.70 bars soil moisture suctions.
The rates of transpiration increased faster than the rate of photosynthesis with increasing soil temperature. The rates of
respiration fluctuated with soil temperature.
Where the ratio of transpiration to photosynthesis is constant
as between 60° F and 80° F at all soil moisture suctions except
0.35 bars, the same process was assumed to be limiting (probably
stomatal control). At 0.35 bars soil moisture suction, physiological
and viscosity factors are to be considered.
The activity of the root is temperature dependent and suction
dependent. At high suctions, the temperature effect is small, at
low suction the temperature effect is large.
At suctions higher than 0.70 bars, the diffusion process is
stomatal controlled.
Genre Thesis/Dissertation
Topic Soil temperature
Identifier http://hdl.handle.net/1957/47897

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