Polymines in Cotton Fiber and Seed

G.H. Davidonis


 
ABSTRACT

The diamine putrescine and the polymines spermidine and spermine appear to be involved in a variety of growth and developmental processes such as cell division, embryogenesis, rooting, flowering and fruit development. Bolls were collected from field- and greenhouse-grown cotton plants (Gossypium hirsutum L. cv. Texas Marker-1 and Deltapine 50) at 5, 7, 9, 14, 21, 28 days post anthesis (dpa). The fiber was separated from the seed and both samples were frozen. Tissue was ground in 5% perchloric acid on ice. Extracts were centrifuged at 1100g and half of the supernatant fraction was also hydrolyzed. samples were benzoylated and analyzed used an HP 1090 liquid chromatograph. The nonhydrolyzed supernatant contained unconjugated (free) polyamines; the hydrolyzed supernatant and pellet fractions contained polyamines liberated from various types of conjugates. No spermine was detected. Free putrescine and spermidine peaked in fiber at 5 dpa while free putrescine and spermidine peaked at 21 dpa and 5 dpa respectively in seed. Putrescine and spermidine in hydrolyzed supernatant fractions reached peaks in fiber at 5 dpa and peaks is seed at 21 dpa. Spermidine decreases with time in fiber pellet samples but showed no decrease in seed pellet samples. The amount of free putrescine in 28 dpa fiber samples was 9 picomoles/gm. fresh wt. and 113 picomoles/gm. fresh wt. in seed samples. Changes in the polyamine progile may be related to fiber elongation since the maximum rate of fiber elongation occurs between 6 and 12 dpa. An important time period in seed development occurs around 21 dpa. At that time starch concentration is at a maximum followed by oil and protein accumulation in the embryo. Peaks in polyamines in the seed also mark this time period.



Reprinted from 1992 Proceedings Beltwide Cotton Conferences pg. 1067
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998