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United States Department of Agriculture

Agricultural Research Service

Research Project: MECHANISTIC PROCESS-LEVEL CROP SIMULATION MODELS FOR ASSESSMENT OF AGRICULTURAL SYSTEMS

Location: Crop Systems & Global Change

Title: Simulation of individual leaf size and canopy development: Approaches to carbon allocation and growth

Authors
item Timlin, Dennis
item Fleisher, David
item Kim, Soo-Hyung
item Yang, Yang
item Reddy, Vangimalla

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 14, 2009
Publication Date: N/A

Technical Abstract: Simulation of individual leaf growth in potato offers many potential benefits as compared to simulation of one ‘big leaf’. These advantages include better simulation of assimilate partitioning, light interception, and nitrogen response and dynamics. In previous research we developed algorithms for simulating individual leaf growth in potato but generalized the model to a single representative leaf representing leaf insertion numbers from 1 to 8 (leaf insertion from the base of the plant upward). As a result, the model could not simulate the bell shaped distribution of leaf areas (larger leaves in the middle of the plant) found on the mainstem of typical potato plants early in their growth. In this research we applied the model to individual mainstem leaves that have emerged before the first flower (insertion numbers 1 to 15). We tested several different approaches to partition assimilate to the leaves with the goal of reproducing a bell shaped distribution of leaf areas. Potential leaf growth was driven by temperature and actual leaf growth controlled by carbon availability. Sunlit and shaded fractions of the leaves were taken into account to estimate light needed for photosynthesis. A photosynthesis model that considers limitations due to light and Rubisco was used. Partitioning assimilate purely on the basis of demand resulted in an irregular distribution of leaf areas along the stem. The best approach was to simulate leaf level photosynthesis and allow each leaf to utilize carbon assimilate for growth to meet the individual leaf’s needs. Extra assimilate was exported to be used in smaller leaves where growth demand for carbon assimilate exceeded the production. Nitrogen, while not accounted for in this model is an important input that needs to be addressed to better simulate carbon partitioning to mainstem leaves in potato.

Last Modified: 12/21/2014
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