Submitted to: Meeting Proceedings
Publication Type: Book / chapter
Publication Acceptance Date: 10/5/2009
Publication Date: 11/4/2010
Publication URL: ISBN: 978-1-60876-187-6
Citation: Sobolev, V.S., Gloer, J.B., Sy, A.A. 2010. Influence of Light Conditions on Biology and Chemistry in the Peanut Plant: Flavonoids and Spermidines from Peanut (Arachis hypogaea) Flowers and Studies of the Photoisomerization of Spermidine Conjugates. In Organic Farming and Peanut Crops. D.C. Grossman and T.L. Barrios, Eds. Nova Science Publishers, Inc., Hauppauge, NY, pp. 65-102. Interpretive Summary: The chapter presents a review on physiology of the peanut plant based on published sources as well as on research conducted at the National Peanut Research laboratory (ARS/USDA). Role of light in vegetative peanut growth, nitrogen fixation, and flowering is discussed. Role of flavonoids and spermidines in plants as well as association of flavonoid and spermidine formation with light exposure is considered as well. Peanut is an economically and nutritionally important crop. Sound seed yield depends heavily on high resistance to pests and uncompromised plant fertility. However, peanut flower constituents that may be responsible for the resistance and fertility have not been studied. The role of light in peanut flowering has been articulated mainly as the results of observations without investigation of specific photochemical mechanisms or compounds involved. The present study revealed the production of flavonoid and spermidine conjugates in the peanut flower at high levels. All of these major metabolites were detected in the flowers for the first time. One of the metabolites has not been previously reported in plants. Flavonoid and spermidine conjugates may play protective roles against pests. The spermidine conjugates may be involved in regulating the plant reproduction process. Future research will concentrate on studies of potential low molecular weight compounds, similar to the spermidines and stilbenoids that may help in breeding pest-resistant cultivars with uncompromised vigor. Collaboration with peanut breeders is foreseen. At present, breeding is the most efficient single technique that allows generation of new prospective peanut varieties. In the past, cross-incompatability factors have limited introduction of favorable genes from wild Arachis spp. into cultivated peanuts. However, this may be circumvented through tissue culture techniques and genetic engineering. Further knowledge of peanut chemistry and physiology may prove to be very valuable in leading to the development of improved peanut cultivars.
Technical Abstract: Early history and significance of the peanut crop is discussed. Annual world production of peanuts at 30 million tons makes this crop one of the most important agricultural commodities. Unusual physiology, inflorescence, and infructescence of the peanut plant make it an attractive object for scientific research. Many physiological processes in the peanut plant, such as vegetative growth, nitrogen fixation, and fertilization are associated with light. Present research revealed high light-sensitivity of the spermidines from the peanut reproductive organ, keel. A new spermidine triamide derivative has been isolated from peanut flowers and identified as acetyldicoumaroylspermidine on the basis of detailed analysis of NMR, MS, and UV data. Two other spermidine conjugates and four flavonoid conjugates that have been previously reported in organs of other plants, have been found in this study in peanut (Arachis hypogaea L.) for the first time. The dynamics of photoisomerization in the spermidine conjugates have been investigated. These flavonoid and spermidine conjugates may play protective roles against pests. New spermidine conjugate may be involved in regulating the plant reproduction process.