|OOSTERHUIS, D - University Of Arkansas|
|KAWAKAMI, E - University Of Arkansas|
|FITZSIMONS, T - University Of Arkansas|
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/18/2011
Publication Date: N/A
Interpretive Summary: Cotton remains an important cash crop for farmers in the southern United States. Under stress (i.e. high temperature or drought), cotton yields are significantly decreased due to excessive boll shedding caused by over-sensitivity to the plant hormone ethylene. The goal of the current study was to evaluate the effect of applying an anti-ethylene compound (1-MCP) at flowering on stress levels and the expression of genes involved in ethylene production in the boll. Open flowers were treated with the anti-ethylene compound and compared to an untreated control. Bolls were collected the following day and the levels of antioxidants (indicators of stress) and the expression of key genes involved in ethylene production were measured. Measurements showed that the anti-ethylene compound reduced the expression of genes involved in ethylene production and lessened the plant’s stress response to ethylene. The application of ethylene inhibitors in the field may be important in lessening the cotton plant’s over-sensitive response to environmental extremes, and could potentially lessen yield losses caused by excessive boll shedding.
Technical Abstract: Cotton remains an important cash crop for farmers in the southern United States. When temperatures rise above 32oC the in vivo fertilization efficiency of cotton is reduced resulting in decreased seed production and potentially decreased yields. Under stress, the plant hormone ethylene is manufactured. 1-Methylcyclopropene (1-MCP) is a synthetic plant growth regulator that binds to the ethylene receptors within the cell preventing the plant from fully recognizing the increased stress levels. 1-MCP was evaluated at the Arkansas Agricultural Research and Extension Center in Fayetteville, AR during the 2009 growing season. Open flowers were treated with 1–MCP on the day of anthesis and compared to an untreated control. Flowers were collected the following day and the levels of antioxidants glutathione reductase and superoxide dismutase, and also malondialdehyde recorded. The ACC-Synthase and ACC-Oxidase gene expressions were also analyzed. Measurements of the antioxidant levels within the cell showed significant differences in glutathione reductase and superoxide dismutase between the two treatments, indicating the 1-MCP was reducing the plant’s response to ethylene. Malondialdehyde levels did not differ between the control and 1-MCP treatment. ACC-Synthase gene expression revealed that the control displayed a higher activity when compared to the 1-MCP treated flowers. Expression of ACC-Oxidase was significantly lower in 1-MCP treated plants than that of the control. The research indicated that 1-MCP is effective at reducing the cotton plant’s perception of stress by reducing oxidative stresses and ethylene production.