2012 Annual Report
1a.Objectives (from AD-416):
Objective 1: Determine the impact of environmental factors of anticipated climate change (e.g., elevated CO2, increased and widely varying temperature, and changes of moisture) on the amounts and types of phytochemicals at harvest, and the persistence of these compounds postharvest, such as during storage at low temperatures, for Brassica crops.
• Sub-objective 1.A. Variety Testing. Evaluate genetically-diverse varieties of kale and broccoli for their responses to elevated temperatures and elevated CO2.
• Sub-objective 1.B. Soil Moisture. Using kale and broccoli varieties, evaluate effects of periodic drought or periodic flooding during cultivation at ambient or elevated CO2 and ambient or elevated temperature regimes.
• Sub-objective 1.C. Postharvest. Using kale and broccoli varieties, determine if elevated CO2 and/or elevated temperature during growth alter the persistence of phytochemicals during postharvest storage at low temperature.
Objective 2: Determine the extent to which soil fertility, CO2, and other environmental stresses, and their interactions, affect changes of phytochemical composition of Brassica crops.
• Sub-objective 2.A. Soil Nitrogen. Using kale and broccoli varieties, evaluate effects of low, intermediate, and high soil N during cultivation at ambient or elevated CO2 and ambient or elevated temperature regimes.
1b.Approach (from AD-416):
Interaction between atmospheric carbon dioxide and other environmental parameters will be investigated in two controlled environments (growth chambers and greenhouses) by raising crops to seed while regulating and monitoring atmospheric CO2, temperature, soil moisture, nutrition, and photosynthetically as well as photomorphogenetically active radiation. Growth chambers will simulate natural conditions. Environmental conditions at various developmental stages will be monitored and compared to those in controlled environments. Work will concentrate on kale (collards) and broccoli. Seeds will be harvested and analyzed by HPLC for important biologically active constituents, including glucosinolates. Effects of environment on biosynthethic pathways will be evaluated.
A previous study that demonstrated effects of elevated CO2 on phytochemical composition in some but not other lines of leaf lettuce and chicory was replicated two times and results are currently being analyzed.
An ultra-performance liquid chromatographic (UPLC) method to analyze major carotenoids (lutein and beta-carotene), vitamin E (alpha- and gamma-tocopherol), and vitamin K (phylloquinone) in green leafy vegetables simultaneously was developed. Numerous techniques were compared to identify conditions that eliminated chlorophyll interference without affecting carotenoids or tocopherols. Phylloquinone was detected and measurable, but was probably partially destroyed by the treatment.