LE3 .A278 2012

2012

Kristie, David

Acadia University

Bachelor of Science

Honours

Biology

Biology

Diurnal rhythms in stem elongation rates (SER) have been studied extensively in many dicots, particularly in the floriculture literature (Neily et al., 2000). In contrast, there have been few studies on the diurnal rhythms of SER and leaf elongation rate (LER) in monocots. In this project, the diurnal rhythms of SER and LER in barley (Hordeum vulgare L. cv.‘Chapais’), oat (Avena sativa L. cv.‘Triple Crown’), and corn (Zea mays L. cv.‘Miracle’), were examined under greenhouse conditions during the summer of 2010 and 2011. Plant growth was also measured in growth chambers under constant light conditions. All measurements were made using rotary motion sensors (RMSs) connected to a LabPro interface. Under greenhouse conditions, corn LER showed a peak during the mid-day, with a trough occurring primarily at night. Oat LER, however, exhibited a broad peak in growth rate during the night. Barley showed a peak in LER during the day for leaves 2 through 4; however, the peak gradually shifted to the night for leaves 5 through 7. The stem elongation rate for oat showed a peak in elongation during the night. For barley, SER showed a peak during the day/night transition. A well-defined rhythm for SER in corn could not be obtained. Under constant light conditions, it was found that barley LER exhibited a free running period of approximately 24 hours. Oat LER also exhibited a free running period of approximately 24 hours under constant light conditions. A free running period of approximately 24 hours indicates that the rhythm in LER in barley and oats is endogenously generated and is under circadian control.

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https://scholar.acadiau.ca/islandora/object/theses:922