My research group focuses on the environmental physiology of ornamental herbaceous plants, with an emphasis on commercial floriculture crops.  In particular, we are investigating how light (quantity, quality, and duration) and temperature (including vernalization) influence growth and development of annual bedding plants, herbaceous perennials, and potted flowering plants.  Three underlying objectives of this research are: 1) to introduce “new” floriculture crops to the greenhouse industry to replace or supplement the production of other, less profitable crops; 2) to improve the production efficiency  of crops currently grown; and 3) to minimize production inputs – with an emphasis on greenhouse energy – to reduce production costs.  The four major foci of my research program are listed below.
 

Managing the Greenhouse Environment for Energy Conservation

With the recent rise in energy costs, some greenhouse growers have lowered their temperature setpoints to reduce fuel consumption for heating.  A lower greenhouse temperature delays crop timing, but surprisingly little information is available on how temperature controls the rate of development of many economically important bedding and perennial plants. We are performing studies to determine how temperature and daily light integral (DLI) regulate plant development during the plug or liner stage and the finish stage. Effects on plant quality, including flowering characteristics, are also being determined. These studies will enable us to predict how changing the greenhouse temperature influences crop timing.  In addition, we’re determining if and when supplemental lighting is a cost-effective strategy to produce garden plants during the transplant and finish stages.  For more information on greenhouse energy, please visit our Greenhouse Energy Cost Reduction Strategies website.

Flowering Physiology of Potted Orchids

Orchids represent the second-most valuable flowering potted crop in the United States, with an estimated wholesale value of $126 million in 2007 (for the 15 U.S. states surveyed). However, with the exception of a few genera, little is known about flower induction and development of orchids. One of my areas of research is to determine how environmental parameters (light and temperature) and exogenous plant hormones control growth and flowering of various orchid hybrids. The overall goal is to develop production schedules to predictably flower various orchids for sales at any time of the year.  Visit our Orchid Research and Development website for more information and our recent publications.

Growth and Development of Herbaceous Perennials

In the past 15 years, one of the major thrusts of the floriculture group at Michigan State University has been to determine the cultural and environmental requirements for production of flowering herbaceous perennials. One main objective continues to be determining how various species respond to photoperiod, vernalization treatments, daily light integral, growing temperatures, and plant growth retardants.  From this information, we can generate production schedules to flower crops of perennials for a predetermined date.  For more information, visit our MSU Perennial Research website.

Plant Growth Regulators on Greenhouse Crops

A constant challenge for many greenhouse growers is to properly manage plant height and architecture of their crops.  For the past several years, we have been quantifying how the timing, method, and rate of application of various PGRs influence growth and development of bedding plants, perennials, and potted plants.  Research continues on products that are currently on the market and on chemicals that are being considered for use with ornamentals.  Information on the use of plant growth retardants on greenhouse crops can be found on our Plant Growth Regulator Research website.
 

Personnel

MAJOR OUTREACH PROGRAMS AND RESOURCES

Books 

Fisher, P. and E. Runkle. 2004. Lighting Up Profits: Understanding Greenhouse Lighting. 98 pp.  Meister Media Worldwide, Willoughby, Ohio. 

Heins, R., A. Cameron, W. Carlson, and E. Runkle. 2000. Firing Up Perennials: The 2000 Edition. 142 pp.  Meister Media Worldwide, Willoughby, Ohio. 

Book Chapters 

Blanchard, M.G., J.A. Chong, J.E. Faust, and E.S. Runkle. 2006. Temperature and light, p. 51-60. In: J.M. Dole and J.L. Gibson (eds.). Cutting propagation: A guide for propagating and producing floriculture crops. Ball Publishing, Batavia, Ill. 

Runkle, E.S., R.D. Heins, A.C. Cameron, and W.H. Carlson. 2002. Manipulating day length to flower perennials, p. 79-83. In: R. Blanchette (ed.). GrowerTalks on Perennials. Ball Publishing, Batavia, Illinois. 

Heins R.D., A.C. Cameron, W.H. Carlson, E. Runkle, C. Whitman, M. Yuan, C. Hamaker, B. Engle, and P. Koreman. 1997. Controlled flowering of herbaceous perennial plants, p. 15-31. In: E. Goto et al. (eds.). Plant production in closed ecosystems. Kluwer Academic Publishers, Netherlands. 

Refereed Journal Publications

Blanchard, M.G. and E.S. Runkle. 2008. Container opacity and media components influence rooting of potted Phalaenopsis and Doritaenopsis orchids. Acta Hort. 788:115-120. 

Rapaka, V.K., J.E. Faust, J.M. Dole, and E.S. Runkle. 2008. Endogenous carbohydrate status affects postharvest ethylene sensitivity in relation to leaf senescence and adventitious root formation in Pelargonium cuttings. Postharvest Biol. Technol. 48:272-282. 

Blanchard, M.G. and E.S. Runkle. 2008. Benzyladenine promotes flowering in Doritaenopsis and Phalaenopsis orchids. J. Plant Growth Regul. 27:141-150. 

Lopez, R.G. and E.S. Runkle. 2008. Effect of temperature and pseudobulb maturity on flowering of the orchid Miltoniopsis Augres ‘Trinity’. Acta Hort. 766:273-278. 

Glady, J.E., N.S. Lang, and E.S. Runkle. 2007. Effects of ethephon on stock plant management of Coreopsis verticillata, Dianthus caryophyllus, and Veronica longifolia. HortScience 42(7):1616-1621. 

Blanchard, M.G. and E.S. Runkle. 2007. Dipping bedding plant liners in paclobutrazol or uniconazole inhibits subsequent stem extension. HortTechnology 17:178-182.

Pramuk, L.A. and E.S. Runkle. 2007. Modeling the effects of temperature and photosynthetic daily light integral on growth and flowering of Salvia splendens and Tagetes patula. J. Amer. Soc. Hort. Sci. 132(3):283-288. 

Runkle, E.S. 2007. Innovative production systems for ornamental potted plants: A case study for Phalaenopsis orchids. Acta Hort. 755:55-59. 

Blanchard, M.G., L.A. Newton, and E.S. Runkle. 2007 Exogenous applications of abscisic acid improved the postharvest drought tolerance of several annual bedding plants. Acta Hort. 755:127-132. 

Rapaka, V.K., J.E. Faust, J. Dole, and E.S. Runkle. 2007. Diurnal carbohydrate dynamics affect postharvest ethylene responsiveness in portulaca (Portulaca grandiflora ‘Yubi Deep Rose’) unrooted cuttings. Postharvest Biol. Technol. 44:293-299. 

Rapaka, V.K., J.E. Faust, J. Dole, and E.S. Runkle. 2007. Effect of time of harvest on postharvest leaf abscission in lantana (Lantana camara L. ‘Dallas Red’) unrooted cuttings. HortScience 42(2):304-308. 

Blanchard, M.G. and E.S. Runkle. 2006. Temperature during the day, but not during the night, controls flowering of Phalaenopsis orchids. J. Exp. Bot. 57:4043-4049. 

Lopez, R.G. and E.S. Runkle. 2006. Temperature and photoperiod regulate flowering of potted Miltoniopsis orchids. HortScience 41:593-597. 

Runkle, E.S. and R.D. Heins. 2006. Manipulating the light environment to control flowering and morphogenesis of herbaceous plants. Acta Hort. 711:51-60. 

Shimizu, H.,  Z. Ma, S. Tazawa, M. Douzono, E.S. Runkle, and R.D. Heins. 2006. Blue light inhibits stem elongation of chrysanthemum. Acta Hort. 711:363-368. 

Lopez, R.G. and E.S. Runkle. 2006. Daily light integral influences rooting and quality of petunia cuttings. Acta Hort. 711:369-373. 

Lopez, R.G. and E.S. Runkle. 2005. Environmental physiology of growth and flowering of orchids. HortScience 40:1969-1973. 

Pramuk, L.A. and E.S. Runkle. 2005. Modeling growth and development of Celosia and Impatiens in response to temperature and photosynthetic daily light integral. J. Amer. Soc. Hort. Sci. 130:813-818.

• Paper received the Alex Laurie Award as the most outstanding research paper published in the ASHS journals in floriculture in 2005 (tie with paper below).

• Paper received the Kenneth Post Award as the most outstanding floriculture research paper published in ASHS journals in 2005

Pramuk, L.A. and E.S. Runkle. 2005. Photosynthetic daily light integral during the seedling stage influences subsequent growth and flowering of Celosia, Impatiens, Salvia, Tagetes, and Viola. HortScience 40:1336-1339.

• Paper received the Alex Laurie Award as the most outstanding research paper published in the ASHS journals in floriculture in 2005 (tie with paper above).

DEPARTMENT OF HORTICULTURE
Michigan State University

Please send your comments to Ms. Sandy Allen allens@msu.edu
This page was last edited in 07/30/08 .