Title: 1-Methylcyclopropene (1-MCP)-induced Alteration in Leaf Photosynthetic Rate, Chlorophyll Fluorescence, Respiration and Membrane Damage Increases Rice (Oryza sativa L.) Yield under High Night Temperature Authors
|Mohammed, Abdul -|
|Cothren, J -|
|Tarpley, Lee -|
Submitted to: Journal of Agronomy and Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 1, 2014
Publication Date: N/A
Interpretive Summary: High night temperature (HNT) is recognized as a cause of yield loss in rice. The HNT is considered to trigger increased production of ethylene, a plant hormone, leading to production of reactive oxygen species, i.e. oxidative stress. Oxidative stress can cause damage to the cellular membranes of leaf tissue, which affects the production, consumption and transfer of photosynthates, resulting in yield loss. In this study, 1-methylcyclopropene (1-MCP), which blocks transduction of the ethylene signal, was examined for its ability to decrease the ethylene effect and help prevent yield and quality losses due to HNT of a popular hybrid rice of the Southern U.S., ‘XL723’. Plants were grown under ambient night temperature (25°C) or HNT (30°C) with or without 1-MCP treatment at the vegetative stage just prior to flowering. The decrease in yield of ‘XL723’ due to HNT was associated with decreased photosynthetic production, increased photosynthate consumption, increased injury to leaf tissue membranes, decreased grains per seedhead and increased chalkiness. Plants under HNT that were treated with 1-MCP performed better, i.e. had increased yield (17%), which was associated with increased photosynthetic production, decreased respiration (39%) and membrane damage (18%), and increased grains per seedhead (11%). The findings further implicate the role of ethylene in HNT-stress induced rice yield losses, and suggest the possibility of 1-MCP application to minimize yield losses due to HNT in rice crops.
Technical Abstract: High night temperature (HNT) can induce ethylene-triggered reactive oxygen species production, which can cause premature leaf senescence and membrane damage, thereby affecting production, consumption and transfer of photosynthates, and yield. The 1-methylcyclopropene (1-MCP) can competitively bind with ethylene receptors and decrease ethylene effects. The objective was to determine the effects of HNT and 1-MCP on leaf photosynthetic rate (PN), chlorophyll fluorescence, total chlorophyll (TC), respiration, membrane damage, pollen germination, spikelet fertility (SF) and yield of rice hybrid ‘XL723’. Plants were grown under ambient night temperature (ANT) (25oC) or HNT (30oC) with or without 1-MCP treatment. Application of 1-MCP was at the boot stage. The decrease in yield (11%) under HNT was associated with decreased PN (4%), stomatal conductance (8%), quantum yield (efficiency of overall photosynthetic process; 11%) TC (23%) and SF (5%) and increased respiration (74%), Fo/Fm (increase in thylakoid membrane damage; 11%) and membrane damage (leaf electrolytic leakage; 57%). The 1-MCP-treated plants grown under HNT showed increased yield (17%), which was associated with increased PN (10%), stomatal conductance (30%), quantum yield (9%), TC (37%) and SF (11%) and decreased respiration (39%), Fo/Fm (5%) and membrane damage (18%). Plants grown under HNT showed increased grain chalkiness (154%) compared to plants grown under ANT.