Spectral Reflectance Imagery and Baseline Analysis of Anthocyanin Concentration in Gossypium Hirsutum L.
Correlations between spectral reflectance imagery and anthocyanin content have the potential to influence the interpretation of imagery data. The objectives of this study were to correlate leaf anthocyanin concentrations in cotton (Gossypium hirsutum L.) leaves with selected types of spectral reflectance imagery, to determine if the imagery could be used as a predictive tool for anthocyanin concentration, and to establish a baseline anthocyanin concentration in cotton leaf tissue. Field experiments were conducted in 2004 near Winnsboro, LA, with both an aerial-based camera and a hand-held device to investigate imagery responses to anthocyanin concentration. Multiple planting and sampling dates were used to produce variation in both anthocyanin concentration and imagery values. Anthocyanin concentration had a positive correlation with increasing sampling date and a negative correlation with planting date confirming that anthocyanin levels increase with crop maturity. The Normalized Difference Vegetation Index (NDVI) values recorded with a NTech GreenSeeker and the Green Normalized Difference Vegetation Index (GNDVI) values obtained from aerial imagery both had a negative and significant (p<0.01) correlation with anthocyanin concentration. NDVI values from the aerial imagery also had a negative relationship, but were not significant (p>0.05). While anthocyanin concentration in cotton leaves have an influence on spectral reflectance imagery, the effect appears to be minimal. Attempts to fit a predictive linear regression model to leaf anthocyanin concentration using spectral reflectance imagery were not successful. Laboratory experiments were also conducted using cotton seeds and cotton seedlings in a germination chamber under irradiation at approximately 100 µmol m-2 s-1 for varying lengths of time. Baseline anthocyanin content for cotton seeds was determined to be approximately 2.0E-6 mol/cm2. A significant (p<0.05) difference was observed between the mean anthocyanin concentrations of seedlings with the first true leaf exposed to 24 hours of continuous light and seeds unexposed to light. No significant (p<0.05) differences were observed in mean anthocyanin concentrations in seedlings with the first true leaf exposed to 12 hours of irradiance or less. No apparent lag period between commencement of irradiance and initiation of anthocyanin production was observed.
Advisor:B. Rogers Leonard; Gerald O. Myers; Alexander M. Stewart
School:Louisiana State University in Shreveport
School Location:USA - Louisiana
Source Type:Master's Thesis
Keywords:agronomy environmental management
Date of Publication:12/15/2005