Abstract
Earlier described data from this laboratory were subjected to primary growth analysis. The plants had been grown in constant conditions of light intensity (200 to 2500 ft-c) and temperature (10° to 30 °C) at five different settings each. Multiple temperature optima were revealed and interpreted. The computed maximum plant growth coefficient was highest in value at 25 °C (plant k mL = 0.44 day −1 ) and secondarily so at 15 °C, but at the experimental light intensities the plant growth coefficient was maximal at 15 °C. The higher temperature optimum was characteristic of roots and "stems" (stem plus leaf sheaths) whose growth coefficients displayed a prominent peak at 25 °C (root k mL ~ 0.8 day −1 , "stem" k mL = 0.4 day −1 ). This optimum was shifted downward with decreasing light intensity until temperature insensitivity was attained at low light intensity. The low-temperature optimum at 15 °C was principally displayed by leaf blades (lamina k mL = 0.47 day −1 ) whose computed maximum growth coefficient also showed a secondary maximum at 25°, but the 15 °C peak was the only one evident at low light intensities. It was tentatively concluded that the 25 °C temperature optimum was that of net translocation, and that the 15 °C temperature optimum was that of net photosynthesis in which photosynthesis was primarily balanced by photorespiration in wheat. The differential growth of the organs represented their relative sink strengths for attracting growth substrate, as dependent on light intensity and temperature. The availability of photosynthate was considered to be the dominating factor in the kinetics of growth free from inorganic limitations. When there was very little photosynthate the tissues benefited from translocation on a "first come first serve" basis. The high values of k mL pushed the absolute maximum plant growth coefficient, k M , of Marquis wheat toward 0.5 or 50% per day, and the basis of the advantage over previous approximations must be elucidated by further experiments. The computed relative efficiency of the use of photosynthate for growth was temperature dependent, but its value at optimum temperature was similar to previous estimates.
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Claims 16
Claim · model-written summary
Computed maximum plant growth coefficient was highest at 25 °C.
Verbatim
e0“The computed maximum plant growth coefficient was highest in value at 25 °C (plant k mL = 0.44 day −1 )”
t0“Marquis wheat”
Claim · model-written summary
At experimental light intensities, plant growth coefficient was maximal at 15 °C.
Verbatim
e0“at the experimental light intensities the plant growth coefficient was maximal at 15 °C”
t0“Marquis wheat”
Claim · model-written summary
Root growth coefficient peaked at 25 °C.
Verbatim
e0“roots and "stems" (stem plus leaf sheaths) whose growth coefficients displayed a prominent peak at 25 °C (root k mL ~ 0.8 day −1 , "stem" k mL = 0.4 day −1 )”
t0“Marquis wheat”
Claim · model-written summary
Stem growth coefficient peaked at 25 °C.
Verbatim
e0“"stems" (stem plus leaf sheaths) whose growth coefficients displayed a prominent peak at 25 °C (root k mL ~ 0.8 day −1 , "stem" k mL = 0.4 day −1 )”
t0“Marquis wheat”
Claim · model-written summary
The 25 °C optimum shifted downward as light intensity decreased.
Verbatim
e0“This optimum was shifted downward with decreasing light intensity until temperature insensitivity was attained at low light intensity”
t0“Marquis wheat”
Claim · model-written summary
Leaf-blade growth coefficient peaked at 15 °C.
Not reportedDirection
Verbatim
e0“leaf blades (lamina k mL = 0.47 day −1 ) whose computed maximum growth coefficient also showed a secondary maximum at 25°”
t0“Marquis wheat”
Claim · model-written summary
Leaf-blade maximum growth coefficient also had a secondary maximum at 25°.
Verbatim
e0“computed maximum growth coefficient also showed a secondary maximum at 25°”
t0“Marquis wheat”
Claim · model-written summary
At low light intensities only the 15 °C leaf-blade peak was evident.
Not reportedDirection
Verbatim
e0“the 15 °C peak was the only one evident at low light intensities”
t0“Marquis wheat”
Claim · model-written summary
Authors tentatively attributed the 25 °C optimum to net translocation.
Not reportedDirection
Verbatim
e0“It was tentatively concluded that the 25 °C temperature optimum was that of net translocation”
t0“Marquis wheat”
Claim · model-written summary
Authors tentatively attributed the 15 °C optimum to net photosynthesis balanced primarily by photorespiration.
Not reportedDirection
Verbatim
e0“the 15 °C temperature optimum was that of net photosynthesis in which photosynthesis was primarily balanced by photorespiration in wheat”
t0“Marquis wheat”
Claim · model-written summary
Organ growth differences represented relative sink strengths depending on light and temperature.
Not reportedDirection
Verbatim
e0“The differential growth of the organs represented their relative sink strengths for attracting growth substrate, as dependent on light intensity and temperature”
t0“Marquis wheat”
Claim · model-written summary
Photosynthate availability was considered the dominant factor in growth kinetics without inorganic limits.
Not reportedDirection
Verbatim
e0“The availability of photosynthate was considered to be the dominating factor in the kinetics of growth free from inorganic limitations”
t0“Marquis wheat”
Claim · model-written summary
With little photosynthate, tissues benefited from translocation on a first-come basis.
- Taxon
- Marquis wheatt0
- Outcome
- tissues benefited from translocatione0
- Qualifier
- very little photosynthatee0
Not reportedDirection
Verbatim
e0“When there was very little photosynthate the tissues benefited from translocation on a "first come first serve" basis”
t0“Marquis wheat”
Claim · model-written summary
The absolute maximum growth coefficient approached 0.5 or 50% per day.
Not reportedDirection
Verbatim
e0“absolute maximum plant growth coefficient, k M , of Marquis wheat toward 0.5 or 50% per day”
t0“Marquis wheat”
Claim · model-written summary
Computed efficiency of photosynthate use for growth depended on temperature.
- Taxon
- Marquis wheatt0
- Treatment
- temperaturee0
- Outcome
- relative efficiency of the use of photosynthate for growthe0
Not reportedDirection
Verbatim
e0“The computed relative efficiency of the use of photosynthate for growth was temperature dependent”
t0“Marquis wheat”
Claim · model-written summary
At optimum temperature, computed efficiency was similar to previous estimates.
Verbatim
e0“its value at optimum temperature was similar to previous estimates”
t0“Marquis wheat”