Overview

I have an appointment of research and extension in nutrition physiology and stress physiology of deciduous fruit crops (apples and grapes in particular). The goal of my reasearch and extension programs is to better understand the physiological processes underlying nutrition and environmental stresses and extend this knowledge to fruit growers for improving productivity and fruit quality. I am also involved in undergraduate and graduate teaching.

Research Focus

The interaction between carbon and nitrogen dominates the primary metabolism in plants, and therefore elucidating this interaction is critical for both optimizing carbon production relative to nitrogen input and understanding the physiology of the whole plant. We are currently focused on how nitrogen supply affects carbon metabolism and nitrogen metabolism in both apples and grapes. Pome and stone fruits of the Rosaceae family, such as apple and cherry, are unique in that sorbitol serves as a primary end-product of photosynthesis and a major translocated carbohydrate in the phloem. Sorbitol is also implicated in responses to environmental stresses. We are using apple trees with decreased sorbitol synthesis to understand the role sorbitol plays in the integrated carbohydrate metabolism, organic acid metabolism and nitrogen metabolism, and stress tolerance. We are also very interested in how apples and grapes respond to environmental stresses, including nutrient deficiency, high light and high temperature. In addition to these fundamental aspects, our research addresses uptake, translocation, storage, and remobilization and demand-supply relationship of nitrogen and other nutrients in apples and grapevines to provide basis for optimizing nutrient inputs into both apple orchards and vineyards.

Outreach and Extension Focus

My extension activities are closely tied with my applied research with the objective of providing our fruit growers with the best nutrient and stress management practices to improve yield and quality of fruit crops in an environmentally sound manner.

Instruction Focus

In addition to graduate advising, I co-teach "Mineral Nutrition of Crops and Landscape Plants" and "Advanced Analytical Techniques in Plant Systems."

Additional Links

• Horticulture physiology research
• Link to CALS Research portal
• Link to CALS Impact statements

Selected Publications

• Cheng, L. and R. Raba. 2009. Accumulation of macro- and micronutrients and nitrogen demand-supply relationship of `Gala`/M.26 trees grown in sand culture. Journal of American Society for Horticultural Science 134(1): 3-13.
• Reidel, E. J., E. Rennie, V. Amiard, L. Cheng, and R. Turgeon. 2009. Phloem loading strategies in three plant species that transport sugar alcohols. Plant Physiology 10.1104/pp.108.134791.
• Xia, G., L. Cheng, A. N. Lakso, and M. Goffinet. 2009. Effects of nitrogen supply on source-sink balance and fruit size of `Gala` apple trees. Journal of American Society for Horticultural Science 134(1): 126-133.
• Chen, L. S., P. Li and L. Cheng. 2008. Effects of high temperature coupled with high light on the balance between photooxidation and photoprotection in the sun-exposed peel of apple. Planta 228: 745-756.
• Li, P. and L. Cheng. 2008. The shaded side of apple fruit becomes more sensitive to photoinhibition with fruit development. Physiologia Plantarum 134: 282-292.
• Li, P., S. Castagnoli and L. Cheng. 2008. Red `Anjou` pear has a higher photoprotective capacity than green `Anjou`. Physiologia Plantarum 134: 486-498.
• Reidel, E. J., R. Turgeon and L. Cheng. 2008. A maltose transporter from apple is expressed in source and sink tissues and complements the Arabidopsis maltose export-defective mutant. Plant and Cell Physiology 49: 1607-1613.
• Zhou, R. and L. Cheng. 2008. Competitive inhibition of phosphoglucose isomerase of apple leaves by sorbitol 6-phosphate. Journal of Plant Physiology 165: 903-910.
• Chen, L. S. and L. Cheng. 2007. The sun-exposed peel of apple fruit has a higher photosynthetic capacity than the shaded peel. Functional Plant Biology 34, 1038-1048.
• Smith, B. R. and L. Cheng. 2007 Iron Assimilation and Carbon Metabolism in `Concord` Grapevines Grown at Different pHs. Journal of American Society for Horticultural Science. 132: 473-483.
• Zhou, R., L. Cheng, and A. M. Dandekar. 2006. Down-regulation of sorbitol dehydrogenase and up-regulation of sucrose synthase in shoot tips of transgenic apple trees with decreased sorbitol synthesis. Journal of Experimental Botany 57: 3647-3657.
• Cheng, L., R. Zhou, E. J. Reidel, T. D. Sharkey, and A. M. Dandekar. 2005. Antisense inhibition of sorbitol synthesis leads to up-regulation of starch synthesis without altering CO2 assimilation in apple leaves. Planta 220: 767-776.
• Smith, B. and L. Cheng. 2005. Photoprotective mechanisms of grape leaves (Vitis labrusca L. cv. Concord) in relation to iron supply. Journal of American Society for Horticultural Science. 130: 331-340.
• Zhou, R. and L. Cheng. 2005. Binding of 3-phosphoglycerate not only activates but also stabilizes ADP-glucose pyrophosphorylase of apple leaves. Functional Plant Biology. 32: 839-848.
• Zhou, R. and L. Cheng. 2004. Biochemical characterization of cytosolic fructose-1,6-bisphosphatase from apple leaves. Plant and Cell Physiology 45: 879-886.
• Chen, L. S. and L. Cheng. 2004. CO2 assimilation, carbohydrate metabolism, xanthophyll cycle and the antioxidant system of `Honeycrisp` apple leaves with zonal chlorosis. Journal of American Society for Horticultural Science 129: 729-737.
• Cheng, L. and F. Ma. 2004. Diurnal operation of the xanthophyll cycle and the antioxidant system in the peel of apple fruit. Journal of American Society for Horticultural Science 129: 313-320.
• Cheng, L., G. Xia and T. Bates. 2004b. Growth and fruiting of young `Concord` grapevines in relation to reserve nitrogen and carbohydrates. Journal of American Society for Horticultural Science 129: 660-666.
• Chen, L. S. and L. Cheng. 2003. Both xanthophyll cycle-dependent thermal dissipation and the antioxidant system are up-regulated in grape (Vitis labrusca L.) leaves in response to N limitation. Journal of Experimental Botany 54: 2165-2175.
• Ma, F. and L. Cheng. 2003. The exposed peel of apple fruit has higher xanthophyll cycle-dependent thermal dissipation and antioxidants of the ascorbate-glutathione pathway than the shaded peel. Plant Science 165: 819-827.
• Cheng, L. 2003. Xanthophyll cycle pool size and composition in relation to nitrogen content of apple leaves. Journal of Experimental Botany 54:385-393.

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