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ARS Home » Southeast Area » Stoneville, Mississippi » Crop Genetics Research » Research » Publications at this Location » Publication #332800

Research Project: Development and Characterization of Soybean Germplasm, Curation of Stored Accessions, and Regional Evaluations of New Genotypes

Location: Crop Genetics Research

Title: Effects of drought and elevated atmospheric carbon dioxide on seed nutrition and 15N and 13C natural abundance isotopes in soybean under controlled environments

Author
item Bellaloui, Nacer
item Abbas, Hamed
item Mengistu, Alemu
item KASSEM, MY - Fayetteville State University

Submitted to: Intech
Publication Type: Book / Chapter
Publication Acceptance Date: 1/17/2017
Publication Date: 5/3/2017
Citation: Bellaloui, N., Abbas, H.K., Mengistu, A., Kassem, M.A. 2017. Effects of drought and elevated atmospheric carbon dioxide on seed nutrition and 15N and 13C natural abundance isotopes in soybean under controlled environments. Intech. 10:133-152.

Interpretive Summary: Global climate changes due to elevated temperature and carbon dioxide is expected to lead to high heat and drought in some regions, affecting crop production, seed nutrition, and food security. Limited information is avaialble on the effects of drought and elevated carbon dioxide on soybean seed nutrition (protein, oil, fatty acids, sugars, and minerals). Therefore, the objective of the current research was to evaluate the effects of drought and elevated carbon dioxide on seed composition (protein, oil, fatty acids, and sugars) and seed nutrition under controlled conditions. Two soybean cultivars of maturity group V were grown under growth chambers. The results showed that drought or drought with elevated carbon dioxide resulted in high protein and oleic acid, but low in oil and linoleic and linolenic acids. Significant decrease of some sugars such as sucrose, glucose, and fructose concentrations was noticed, but high content of sugars raffinose and stachyose was observed. Major elements such as nitrogen, phosphorus, and potassium, and some micro-nutrients were reduced under drought or drought with normal or elevated carbon dioxide concentrations. Using natural abundance of nitrogen and carbon isotopes, results showed that nitrogen and carbon metabolism were altered under drought or drought with ambient or elevated carbon dioxide. The current research demonstrated that global climate changes may lead to changes in seed nutrition, and nitrogen and carbon metabolism. Higher protein under drought could be due lower seed size. Lower oil is due to the genetically inverse relationship between protein and oil. Higher oleic fatty acid and lower linolenic fatty acid are desirable traits for oil stability and shelf-live. The research further provides a new knowledge on the understanding of the effects of drought and elevated carbon dioxide on seed nutrition, and creates opportunities to breeders to select for drought tolerant with elevated carbon dioxide varieties to maintain high seed nutritional value seeds. Efforts of breeders to select for these traits will sustain food source and food security for humans and livestock as soybean is a major source for protein and oil for human consumption and soymeal for animals.

Technical Abstract: Global climate changes due to elevated temperature and CO2 is expected to lead to high heat and drought in some regions, affecting crop production and seed nutrition. Soybean is one of the most valuable crops worldwide because of its content of protein (40%) and oil (20%), fatty acids, amino acids, carbohydrates (30%), crude fiber (5%), and ash (5%). It also contains minerals such as P, K, Ca, Mg, Fe, Cu, Mn, Zn, Mo, and vitamins B1, B2, B6, and phytoestrogen such isoflavones, and phenolics. Limited information is avaialble on the effects of drought and elevated CO2 on seed nutrition (protein, oil, fatty acids, sugars, and minerals). The objective of the current research was to evaluate the effects of drought and elevated CO2 on seed composition and seed nutrition under controlled conditions. Two cultivars of maturity group V were grown under greenhouse conditions until seed-fill stage, then transferred to growth chambers till full maturity. The plants then were subjected to the following four treatments (T): T1= plants were grown under irrigated and subjected to 360 µmol mol-1 CO2 concentration; T2= plants were grown under irrigated and subjected to 700 µmol mol-1 CO2 concentration; T3= plants were grown under drought and subjected to 360 µmol mol-1 CO2 concentration; T4=plants were grown under drought and subjected to 700 µmol mol-1 CO2 concentration. Drought treatment was imposed by growing the plants at soil water potential of about -199 kPa. For irrigated plant, soil water potential was kept at about -15 to -20 kPa. Soil water potential was monitored by using soil water potential sensors. For irrigated experiment, the plants were watered as needed. The results showed that drought or drought with elevated CO2 resulted in high protein and oleic acid, but low in oil and linoleic and linolenic acids. Significant decrease of sucrose, glucose, and fructose concentrations was noticed, but high content of raffinose and stachyose was observed. Macro-nutrients such as N, P, K, and some micro-nutrients were reduced under drought or drought with normal or elevated CO2 concentrations. Seed '' 15N (15N/14N ratio) and '' 13C (13C/12C ratio) natural abundance isotopes were also altered under drought or drought with ambient or elevated CO2 concentrations, reflecting nitrogen and carbon metabolism changes. The current research demonstrated that global climate changes may lead to changes in seed nutrition, and nitrogen and carbon metabolism. Higher protein could be due lower seed size, and lower oil is due to the genetically inverse relationship between protein and oil. Higher oleic fatty acid and lower linolenic fatty acid are desirable traits for oil stability and shelf-live. The current book-chapter further provides a new knowledge on the understanding of the effects of drought and elevated CO2 on seed nutrition and creates opportunities to breeders to select for drought tolerant and elevated CO2 tolerant varieties to maintain high seed nutritional value seeds.