Dr. Leonid Kurepin
Plant growth regulator analysis biotic and abiotic stress
2011 – current – Postdoctoral Fellow at University of Western Ontario, Supervisors: Mark Bernards and Vojislava Gbric
2010 – 2011 – Postdoctoral Fellow at Trent University, Supervisor: R.J. Neil Emery
2005 – 2010 – Postdoctoral Fellow at University of Calgary, Supervisors: Richard P. Pharis and David M. Reid
2001 – 2005 – PhD program (Plant Hormone Physiology) at University of Calgary, Supervisors: Richard P. Pharis and David M. Reid
1998 – 2000 – BSc program (Biology) at Tel-Aviv University
Developmental processes in plants with emphasis on the interactions of environmental cues and hormone signalling at the physiological and functional genomics levels.
Plant Hormone Physiology:
Plants, unlike animals, do not have a central nervous system and therefore have to relay on messengers, small chemicals, to transfer information along the body of the plant. These small chemicals are called plant hormones, which unlike animal hormones can be synthesized and elicit their action in the same cell or tissue. Plant hormones controll all aspects of plant growth and development, from seed germination to scenesence. At least eight naturally occuring plant chemicals are recognized today by most scientists as plant hormones: auxins, ethylene, gibberellins, abscisic acid, cytokinins, brassinosteroids, salycilic acid and jasmonic acid.
Interactions Between Plant Hormones:
Any biotic or abiotic change in plant's habitat will be sensed by plant and the information will be trasferred via plant hormone (or a group of plant hormones) to the entire body of the plant in order to adapt to changing environment. Unfortunately for plant scienteist who study such phenomena, the environmental cue (for example drought) affects the levels of more than one plant hormone which in turn can affect the production or perception (or both) of other plant hormones. Therefore, a simple event in plant's habitat may elicit endogenous changes in levels of multiple plant hormones, where each has a different role in plant's ability to cope with drought.
Plant Stress Physiology:
What is "stress"? Stress is any biotic or abiotic signal that can change plant's habitat for an X amount of time which is enough to disbalance plant homeostasis. Water ability, light quality and quantaty, nutrient and salt distribution in soil, wind, heavy rain, pathogen attact, wounding, extreme temperatures for plant growing season are just a few examples of stresses which can affect plant growth and development. These environmental signals affect the levels of not only classical "stress" hormones, such as ethylene, abscisic acid, jasmonic acid and salycilic acid, but can also affect the levels of other plant hormones, and therefore creating a web of plant hormone interactions.
Light Regulation of Plant Growth and Development:
Light is the driving force behind photosynthesis, i.e. life on Earth (oxygen + sugar). However, light has also photomorphogenic effect on plant growth and development. Light has been shown to regulate a pleotropy of responses, from seed germination to flower and fruit development. Plants percieve light via at least three classes of photoreceptors: phytochromes, cryptochromes and phototropins. The light signal is then transmitted by plant hormones into morphological and/or developmental plant processes. Plant photoreceptors, as plant hormones, can also interact with each other and together they create a complex web of light-hormone-growth/development cross interactions.
Flower, Fruit and Seed Development:
Flower initiation is perhaps the most interesting topic for plant scientists, as the signal (presumbaly a plant hormone or multiple hormones) responsible for it is still unknown. The development of flower with subsequesent fruit and seed development is yet another example where a complex web of plant hormone interactions exists. Further, distinct plant species have developed different and sometimes opposite webs of plant hormone interactions to regulate flower, fruit and seed development. Also, when environmental signal, such as light, is introduced into hormonally-regulated plant developmental system, it can completely change the plant hormone interactions.
This page was last updated on
November 24, 2010
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