Abstract
Abstract Production estimates based on photosynthate accumulation are affected by changes in photosynthesis rates related to aging in different cultivars. The influence of leaf and plant age on photosynthetic rates was investigated in six maize ( Zea mays L.) cultivars with maturity ratings ranging from <2300 to >3500 CHU (corn heat units). Photosynthesis and irradiance measurements were fitted to rectangular hyperbolas using a nonlinear fitting technique. These curves were analyzed as a function of cultivars, and leaf and plant age. For comparison among cultivars and age groups, photosynthesis was represented by P 2000 (net photosynthetic rate at irradiance (I) = 2000 µ mol m −2 s −1 ). In all cultivars, early leaves had lower P 2000 values at a given leaf age than late maturing leaves. The P 2000 values tended to increase to a maximum at the time of full individual leaf expansion and then decrease. The duration of maximum P 2000 values for leaves nearest the ear were longer than for earlier or later developing leaves. Leaves nearest the ear for early maturing cultivars tended to have lower P 2000 values than later maturing cultivars at comparable leaf ages. Plant photosynthesis patterns were the same for all cultivars in relation to plant age and phenological development. Photosynthesis ( P 2000 ) was low for the six‐leaf stage, reached a maximum just before tasselling, and then declined during brown silk, blister, and dent stages. A quadratic equation described the relationship between P 2000 and plant age. The trend was for latermaturing cultivars to have significantly (P < 0.05) larger P 2000 values than earlier‐maturing cultivars at comparable phenological stages. Significant cultivar differences were found in leaf development rate and length of vegetative period (P < 0.10).
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Claims 8
Claim · model-written summary
Across the six maize cultivars, P 2000 tended to rise to a maximum at full individual leaf expansion and then decrease.
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Six Maize Cultivars”
e0“The P 2000 values tended to increase to a maximum at the time of full individual leaf expansion and then decrease”
Claim · model-written summary
In all cultivars, early leaves had lower P 2000 values at a given leaf age than late maturing leaves.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Six Maize Cultivars”
e0“In all cultivars, early leaves had lower P 2000 values at a given leaf age than late maturing leaves”
Claim · model-written summary
The duration of maximum P 2000 was longer for leaves nearest the ear than for earlier or later developing leaves.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Six Maize Cultivars”
e0“The duration of maximum P 2000 values for leaves nearest the ear were longer than for earlier or later developing leaves”
Claim · model-written summary
Leaves nearest the ear of early maturing cultivars tended to have lower P 2000 than those of later maturing cultivars at comparable leaf ages.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Six Maize Cultivars”
e0“Leaves nearest the ear for early maturing cultivars tended to have lower P 2000 values than later maturing cultivars at comparable leaf ages”
Claim · model-written summary
Plant photosynthesis (P 2000) was low at the six-leaf stage, peaked just before tasselling and declined during brown silk, blister and dent stages, the same pattern in all cultivars.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Six Maize Cultivars”
e0“Photosynthesis ( P 2000 ) was low”
e1“reached a maximum just before tasselling, and then declined during brown silk, blister, and dent stages”
Claim · model-written summary
A quadratic equation described the relationship between P 2000 and plant age.
- Outcome
- relationship between P 2000 and plant agee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Six Maize Cultivars”
e0“A quadratic equation described the relationship between P 2000 and plant age”
Claim · model-written summary
Later-maturing cultivars had significantly larger P 2000 values than earlier-maturing cultivars at comparable phenological stages.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Six Maize Cultivars”
e0“to have significantly (P < 0.05) larger P 2000 values than earlier”
Claim · model-written summary
Significant cultivar differences were found in leaf development rate and in length of the vegetative period.
- Outcome
- leaf development rate and length of vegetative periode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Six Maize Cultivars”
e0“Significant cultivar differences were found in leaf development rate and length of vegetative period (P < 0.10)”