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ARS Home » Research » Publications at this Location » Publication #121857


item Ort, Donald
item Long, Stephen

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 4/11/2002
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: All energy contained in food we eat is ultimately derived from sunlight through the process of photosynthesis. Solar energy input sets the upper limit on energy that can be transformed into crop yield, actual yield of energy in food depends on the product of solar input and efficiency with which solar energy is transformed into harvested product. Sucrose and other photosynthate formed in leaves are exported to heterotrophic plant organs to provide energy for growth and storage. In addition to being basic energy currency of plants, sucrose and other photosynthate also act as regulatory compounds able to signal balance between demand and photosynthetic production. On a daily basis crop plants encounter light energy that exceed their photosynthetic capacity. Plants have evolved a sophisticated set of regulatory photoprotective measures that safeguard plants but at significant cost to photosynthetic efficiency. Significant improvements in production of some crops may be possible by introducing steeper leaf angles thereby reducing the amount of excess light at the top of canopies and allowing greater light penetration to otherwise shaded leaves. Plants also frequently encounter a variety of environmental stresses that exacerbate the need to engage photoprotective measures as well as diminish photosynthetic efficiency in other ways. There are compelling reasons to believe that understanding how plants cope with stressful environments will accelerate improvement of crops.