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 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 carbohydrate metabolism, organic acid metabolism and nitrogen metabolism, and stress tolerance. We are very interested in both primary metabolism and secondary metabolism relevant to fruit quality during fruit growth and development as well as their responses to nutrient stress and other environmental stresses. On the more applied side, 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

The goal of my extension program is to effectively deliver research-based, up to date information and provide expertise concerning nutrient management to the apple and grape industries in New York through collaborations with faculty, extension educators, and growers. Extension is a two-way communication. On one direction, we deliver information to growers after learning their needs. On the other direction, growers provide feedbacks on our extension programs and communicate their needs for applied research and extension, which make our work more relevant and effective. My extension activities are closely tied with my applied research. The current foci are 1) management of nitrogen and other essential nutrients to improve yield and quality of high density apple plantings; 2) nitrogen management to improve the productivity of juice grapes and yeast available nitrogen levels in winegrape musts.

Teaching Focus

My goal in teaching and advising is to train students so that they develop to realize their academic potential, resulting in not only getting a degree from Cornell, but more importantly becoming a “thinker” and a “doer” in the field of horticultural sciences. My teaching has been largely in mineral nutrition of fruit crops and advanced analytical techniques in plant science.

Additional Links

• Horticulture physiology research
• Link to CALS Research and Impact
• Link to Research & Expertise Across Cornell

Selected Publications

Journal Publications

• Li, M., Feng, F., & Cheng, L. (2012). Expression patterns of genes involved in sugar metabolism and accumulation during apple fruit development. PLoS One. 7:e33055.
• Fu, Q., Cheng, L., Guo, Y., & Turgeon, E. G. (2011). Phloem loading strategies and water relations in trees and herbaceous plants. Plant Physiology. 157:1518-1527.
• Wang, H., & Cheng, L. (2011). Differential effects of nitrogen supply on skin pigmentation and flesh starch breakdown of ‘Gala’ apple. HortScience. 46:1116-1120.
• Wang, H., Ma , F., & Cheng, L. (2010). Metabolism of organic acids, nitrogen and amino acids in chlorotic leaves of ‘Honeycrisp’ apple (Malus domestica Borkh) with excessive accumulation of carbohydrates. Planta. 232:511-522.
• Zhang, Y., Li , P., & Cheng, L. (2010). Developmental changes of carbohydrates, organic acids, amino acids, and phenolic compounds in ‘Honeycrisp’ apple flesh. Food Chemistry. 123:1013-1018.
• Reidel, E. J., Rennie, E., Amiard, V., Cheng, L., & Turgeon, E. G. (2009). Phloem loading strategies in three plant species that transport sugar alcohols. Plant Physiology. 149:1601-1608.
• Xia, G., Cheng, L., Lakso, A. N., & Goffinet, M. C. (2009). Effects of nitrogen supply on source-sink balance and fruit size of Gala apple trees. Journal of American Society of Horticultural Science. 134:126-133.
• Cheng, L., & Raba, R. M. (2009). Accumulation of macro- and micronutrients and nitrogen demand-supply relationship of ‘Gala’/M.26 trees grown in sand culture.. Journal of American Society of Horticultural Science. 134:3-13.
• Chen, L., Li, P., & Cheng, L. (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.
• Reidel, E. J., Turgeon, E. G., & Cheng, L. (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. 49:1607-1623.

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