Research

Plant Ecophysiology

The way different environmental conditions affect plant function, especially photosynthesis is fascinatingly unpredictable. I am especially interested in studying how light-dependent and carbon assimilatory processes adjust in response to environmental stress. I also attempt to find if useful phytochemicals are elicited during such adjustments.

Continuing work

Comparative physiology of wild type (TM) and immature mutant (im) cotton – with Dr. Hee Jin Kim, USDA, New Orleans.

Identification of smooth cord grass genotypes with possible tolerance to petroleum oil

photo
Physiological measurements on smooth cord grass in Barataria Bay, LA after the 2010 oil spill. August, 2012.

Some past work

Ratnayaka HH*, Boue S, Dinh T**, Le SB**, Cherubin R**. 2018. Photosynthesis  and kaempferol yields of soy leaves under ABA application and mechanical wounding. Journal of Plant Biochemistry and Physiology 6:215;  doi: 10.4172/2329-9029.1000215

Ratnayaka HH*. 2017. An on-campus botanical tour to promote student satisfaction and learning in a university level biodiversity or general biology course. Education Sciences (1), 18; doi:10.3390/educsci7010018

Ratnayaka HH*, Molin WT, Sterlin g TM. 2012. Comparison of physiological and antioxidant responses of Anoda cristata and cotton to progressive drought. Weed Research 52: 358-366.

Bettmann GT, Ratnayaka HH, Molin WT, Sterling TM. 2006. Physiological and antioxidant responses of cotton and spurred anoda (Anoda cristata) under nitrogen deficiency. Weed Science 54:641-650.

Molin WT, Hugie JA, Ratnayaka HH, Sterling TM. 2006. Spurred anoda (Anoda cristata) competition in wide row and ultra narrow row cotton (Gossypium hirsutum and G. barbadense) management systems. Weed Science 54:651-657.

Ratnayaka HH*, Kincaid D. 2005. Gas exchange and leaf ultrastructure of Tinnevelly senna, Cassia angustifolia, under drought and nitrogen stress. Crop Science 45:840-847.

Ratnayaka HH*, Molin WT, Sterling TM. 2003. Physiological and antioxidant responses of cotton and spurred anoda under interference and mild drought. Journal of Experimental Botany 54:2293-2305.

Ratnayaka HH*, Meurer-Grimes B, Kincaid DT. 2002. Sennoside yields in Tinnevelly Senna affected by deflowering and leaf maturity. HortScience 37:768-772.

Ratnayaka HH*, Meurer-Grimes B, Kincaid DT. 1998. Increasing sennoside yields in Tinnevelly Senna (Cassia angustifolia Vahl): Effects of drought, foliar nitrogen spray and crop type. Planta Medica 64:438-442.

Ratnayaka HH*, Bandara KMC, Weerasinghe ASP. 1993. Cropping systems development with Solanum xanthocarpum in Mahaweli system C of Sri Lanka. Tropical Science 33:163-170.

Ratnayaka HH. Sangakkara UR. 1988. Cowpea (Vigna unguiculata Walp) as a component of alley cropping. Sri Lankan Journal of Agricultural Science 25:75-82.

* Corresponding author, ** Xavier student

Some student presentations since 2015

Marrero E*, Wilson A, Kim HJ, Ratnayaka HH. 2021. Cotton immature fiber imPPR mutant performs gas exchange differently compared with its isogenic wild type. Plant Biology Worldwide Summit. American Society of Plant Biologists Annual Conference. July 19 – 23. Online. https://www.eventscribe.net/2021/ASPB/fsPopup.asp?Mode=posterinfo&PosterID=404253&query=cotton

Marrero E*, Nguyen A, Kim HJ, Ratnayaka HH. 2020. An analysis of growth characteristics of cotton immature fiber mutant, im, compared with its near isogenic wild type, TM‐1. ERN Conference in STEM. February 6 – 8. Washington, D.C. https://emerging-researchers.org/projects/153-3/

Marrero E*, Vu A, Vu T, Johnson C, Kim HJ, Ratnayaka HH. 2019. Carbon assimilation and fast fluorescence kinetics between cotton thinner fiber mutant, im, and its near isogenic wild type, TM-1, under controlled environment. American Society of Plant Biologists Annual Conference. Aug 3 – 7, San Jose, CA.  https://plantbiology.aspb.org/wp-content/uploads/2020/01/Plant-Biology-2019-Posters.pdf – p.557.

Vu A*, Vu T, Stern K, Johnson C, Arasah A*, Kim HJ, Ratnayaka HH. 2018. Gas exchange and light harvesting properties between cotton immature fiber mutant, im, and its near isogenic wild type, TM-1, that differ in fiber wall thickness. American Society of Plant Biologists Annual Conference. July 14 – 18, Montreal, Canada. https://www.eventscribe.com/2018/ASPB/PosterTitles.asp?goToLetter=G&pfp=PosterTitles

Johnson C*, Vu T*, Opusunju N, Arasah A*, Stern K*, Kim HJ, Ratnayaka HH. 2017. Comparative photosynthetic physiology of near isogenic cotton lines differing in the  degree of fiber cell wall thickness in cotton (Gossypium hirsutum L.). American Society of Plant Biologists Annual Conference. June 24-28, Honolulu, HI. Poster # 1200-012. https://www.eventscribe.com/2017/ASPB/PosterTitles.asp?h=Posters%20and%20Abstracts

Gordon M*, Arasah A*, Stern K*, Kim HJ, Ratnayaka HH. 2016. Photosynthesis and growth characteristics of cotton immature fiber mutant (im) in comparison with isogenic wild type (TM-1). American Society of Plant Biologists Annual Conference. July 9-13, Austin, TX. http://www.eventscribe.com/2013/ app/tweets.aspAccountID=9908822&EventID=2088&ClientID=253&PresentationID=&BoothID=&PresenterID=&PosterID=63587

Opusunju N*, Humphrey A*, Gabriel K*, Ugbaja C*, Combe S, Boue S, Ratnayaka HH. 2015. Photosynthetic physiology and kaempferol yield affected by leaf treatments in soy plants. American Society for Horticultural Science Annual Conference. August 4-7, New Orleans, LA. https://ashs.confex.com/ashs/2015/poster/papers/index.cgi?username=21392&password=523062

Undergraduate author is underlined.