Recipient Organization
LINCOLN UNIVERSITY
820 CHESTNUT ST
JEFFERSON CITY,MO 651023537
Performing Department
(N/A)
Non Technical Summary
Project SummaryVegetables of the family Brassicaceae (Brassica vegetables), which includes collards, possess vitamins, and anti-carcinogenic and antioxidant properties. Brassica vegetables are rich dietary sources of glucosinolates (precursors to a group of anti-carcinogenic isothiocyanates). Collards (Brassica oleraceaL. Acephala) are associated with African American cuisine in the southern U.S., but hydroponic growing allows a more widespread small-scale production of this crop locally under different climates nationwide. In addition to carbohydrates, proteins, and essential minerals the USDA-ARS database reports that 100 g fresh weight of raw collards contains as much as 546.4% of the daily value of vitamin K, which plays a key role in helping the blood to clot and prevent excessive bleeding; vitamin A (8.4% beta-Carotene and 16.7% retinol), 58.8% vitamin C, 8.3% vitamin B6, and 7.6% riboflavin (vitamin B2). This research will utilize current expertise and acquired knowledge from over a decade of hydroponic crop production research at Lincoln University-Missouri to identify crop management-associated variability of health-beneficial glucosinolates in collards. Increased understanding of cropping practices appropriate to produce collards with higher and consistent concentrations of glucosinolates enhances the development of hybrids with improved dietary qualities. Proposed approaches to executing this project involve growing collards in NFT hydroponic culture and extracting leaf-, stem, and root tissue for chemical analysis. Total glucosinolates, vitamin K, and carotenoids will be identified and quantified by gas-liquid chromatography from the products of hydrolysis, isothiocyanates, and oxazolidine,2,thiones. Confirmation of the identity of aglucons from each collard cultivar will be made by a UHPLC/MS/MS tandem system.
Animal Health Component
35%
Research Effort Categories
Basic
55%
Applied
35%
Developmental
10%
Goals / Objectives
Goal 1: Generate data for cultivar selection and subsequent genetic crop improvement of collard greens (Brassica oleracea L. Acephala group) by characterizing pre-harvest crop management induced variation in leaf content of health-beneficial indole (indol-3-ylmethylglucosinolates [glucobrassicin, neoglucobrassicin, and 4-methoxyglucobrassicin]), and aliphatic (3-methylsulfinyl- alkylglucosinolates [glucoiberin and glucoraphanin and sinigrin]) in a commercial hydroponic culture system. Objective (1a): To quantitatively determine plant mineral nutrition induced variations in leaf-, stem, and root content of total and individual indole (indol-3-ylmethylglucosinolates [glucobrassicin, neoglucobrassicin and 4-methoxyglucobrassicin]), and aliphatic (3-methylsulfinylalkylglucosinolates [glucoiberin, glucoraphanin, and sinigrin]) in collard green cultivars under greenhouse hydroponic culture. Objective (1b): Determine cultivar x mineral nutrition interaction effects on the content of health-beneficial indole (indol-3-ylmethylglucosinolates [glucobrassicin, neoglucobrassicin and 4-methoxyglucobrassicin]), and aliphatic (3-methylsulfinylalkylglucosinolates [glucoiberin and glucoraphanin and sinigrin]) in the leaf-, stem, and root of collard greens under greenhouse hydroponic culture. Objective (1c): Assess the quantitative variation in leaf total indole (indol-3-ylmethylglucosinolates) and aliphatic (3-methylsulfinylalkylglucosinolates) in cultivars of collard greens induced by biotic stress (wounding through sequential harvesting of leaves) from greenhouse hydroponic culture. 2. Goal 2: Ascertain statistical correlations between the leaf content of health-beneficial indole and aliphatic glucosinolates and selected dietary nutrients (vitamins A, B, C, D, E, and K) in collard green cultivars grown under greenhouse hydroponic culture.Objective:(2). To examine the statistical associations (correlations) between the leaf total indole (indol-3-ylmethylglucosinolates), aliphatic (3-methylsulfinylalkylglucosinolates), and selected dietary nutrients (vitamins A, B, C, D, E and K) in collard greens cultivars from greenhouse hydroponic culture.
Project Methods
Research Methodologya. Plant culture.For all experiments in this research project, plants will be raised from seed, transferred into NFT culture at the two true-leaf stage, and grown to commercial maturity in a protected hydroponic culture system. Experiments will be conducted in two existing 134 sq.-meter (1,440 sq. ft.) controlled environment hydroponic greenhouses on the Lincoln University-Missouri campus in Jefferson City, using the existing Nutrient Film Technique [NFT] hydroponic system. The NFT modules are representative of standard commercial hydroponic modules used in the hydroponic industry to produce leafy-green vegetables. Collard green leaves will be harvested for growth, yield measurements, and chemical analysis.b. Detailed Approach to Specific Experiments1. Objective (1a).To quantitatively determine plant mineral nutrition induced variations in leaf-, stem, and root content of total and individual indole (indol-3-ylmethylglucosinolates [glucobrassicin, neoglucobrassicin and 4-methoxyglucobrassicin]), and aliphatic (3-methylsulfinylalkylglucosinolates [glucoiberin, glucoraphanin and sinigrin]) in collard green cultivars from hydroponic culture. Two sets of cultivars raised from seed will be transferred into NFT culture. Collard green seedlings will be grown until the bottom four to five leaves from the shoot tip are fully expanded but still tender (commercial maturity) at ambient greenhouse day/night temperature, relative humidity, and photoperiod (natural day/night lighting cycle). Experiments will compare the response of tissue total and individual glucosinolate content and biological yield of collard green grown with three nutrient solution formulations (base Steiner nutrient solution [FERT] treatments). Two of the FERT comprises different concentrations of NaNO3 (2.0 and 5.0 mM) containing a combination of Ca(NO3)2.4H2O and KNO3 (as additional sources of Nitrate-nitrogen (N). The third FERT (control treatment) consists of a modified Steiner base nutrient solution with optimum concentration of Ammoniacal-N as (NH4)2HPO4and (NH4)2SO4plus Ca(NO3)2.4H2O and KNO3as sources of Nitrate-N. Three cycles of NFT experiments will be conducted, each with two sets of cultivars (a '2 x 3' (cultivar x FERT) factorial experiment. Nutrient solution pH, EC, N, K, Ca, Na, and petiole-sap nitrogen concentration data will be collected and used to determine the frequency of refreshing the nutrient solution. Leaves from crops harvested for yield and growth measurement will be sampled for elemental analysis. For organic compound analysis of cultivars, comparative analysis of the leaf-, stem, and root total indole (indol-3-ylmethylglucosinolates) and aliphatic (3-methylsulfinylalkylglucosinolates) will be conducted during the three to four sequential leaf harvesting cycles of each NFT experiment for objective-1(a). Data from all experiments to accomplish objective-1(a) will be analyzed statistically as described in section c below.2. Objectives 1(b).Determine cultivar x mineral nutrition interaction effects on the content of health-beneficial indole (indol-3-ylmethylglucosinolates [glucobrassicin, neoglucobrassicin and 4-methoxyglucobrassicin]), and aliphatic (3-methylsulfinylalkyl-glucosinolates [glucoiberin, glucoraphanin and sinigrin]) in the leaf-, stem, and root of collard greens under greenhouse hydroponic culture. The two collard green cultivars grown to commercial maturity in the three hydroponic nutrient solutions under objective-1(a) above will be sampled and analyzed statistically as a '2 x 3' (cultivar x FERT) factorial experiment. Cultivar x FERT interaction effects will be determined in leaf-, stem-, and root tissue for total glucosinolates indole (indol-3-ylmethylglucosinolates), and aliphatic (3-methylsulfinylalkyl-glucosinolates) content.3. Objectives 1(c).Assess the quantitative variation in leaf total indole (indol-3-ylmethylglucosinolates) and aliphatic (3-methylsulfinylalkylglucosinolates) in cultivars of collard greens induced by biotic stress (wounding through sequential harvesting of leaves) from greenhouse hydroponic culture. The two collard green cultivars will be grown to commercial maturity in the three hydroponic nutrient solutions as described in 1(a) above and will be sampled and analyzed statistically as a '2 x 3' (cultivar x FERT) factorial experiment. Plant tissue will be biochemically analyzed for total indole (indol-3-ylmethylglucosinolates) and aliphatic (3-methylsulfinylalkyl-glucosinolates) glucosinolates content. Biotic stress-induced variation in leaf glucosinolate and dietary nutrient content will be determined from 10 seedling plants of each FERT treatment during the first leaf harvest of each experiment for objective 1a, and in subsequent 4 to 5-week sequential leaf harvesting. Data will be statistically analyzed using the multivariate repeated measures method of the SAS (SAS Institute, Inc., Cary, NC), and as described in Section C below to determine any variability in tissue glucosinolate and dietary nutrient content resulting from sequential harvesting over time, and if the leaf glucosinolate concentrations vary between the first and subsequent sequential harvesting.4. Objective 2.To examine statistical associations (correlations) between the leaf total indole (indol-3-ylmethylglucosinolates), aliphatic (3-methylsulfinylalkylglucosinolates) and selected dietary nutrients (vitamins A, B, C, D, E and K) in collard green cultivars from greenhouse hydroponic culture. This experiment will involve a comparative evaluation to determine associations between the leaf total indole glucosinolates (indol-3-ylmethylglucosinolates), and aliphatic glucosinolates (3-methylsulfinylalkylglucosinolates) content versus the content of dietary nutrients (vitamins A, B, C, D, E, and K) of collard greens grown for objective 1a experiments. Leaves from 10 plants of each treatment will be analyzed for their total and individual content of glucosinolates as well as the dietary nutrients (vitamins A, B, C, D, E, and K). The association between the groups of glucosinolates and the individual dietary nutrients will be determined by correlation analysis using the SAS software (SAS Institute, Cary, NC).c. Experimental Design and Statistical Analysis.Several cropping cycles (as appropriate for objectives 1 through 2), each involving different combinations of cultivars and three nutrient solution formulations (FERT) will be completed in three NFT hydroponic modules. Each module comprises six channels (360 cm long; [rows]) with plants spaced 20 cm apart along the rows. The three modules (blocks) will be divided into three plots with two rows per plot. Each experiment will consist of a randomized complete block (RCB) design with FERT as the main factor (one FERT treatment/block). There will be N = 108 plants per treatment for each of the two cultivars per experiment in a 2 x 3 (cultivar x FERT) factorial experiment. Repeated measures analysis for linear mixed models with normally and non-normally distributed data will be employed for the same response variables above that are obtained from plant samples harvested sequentially using the "Generalized Linear Mixed Model ([GLIMMX]" procedure of SAS as an alternative to the "Method of Least Squares" when it is most applicable. Pair-wise comparisons of Least Squares Means will be conducted with the Tukey-Kramer adjustment, while the Kenward-Roger correction will adjust the standard error estimates and test statistics in PROC GLIMMX. The glucosinolates patterns of the treatments (cultivar x FERT) will be determined as the relative amounts of the total and individual indole glucosinolates (indol-3-ylmethyl-glucosinolates) and aliphatic glucosinolates (3-methylssulfinylalkylglucosinolates) in collards. Cultivars and treatments that exhibit high correlations in their glucosinolate and/or dietary nutrient patterns will be grouped together.