Cotton seeds are a valuable resource. Manufacturers produce margarine, soaps, and cosmetics from oils found in cotton seeds. When the seeds are processed they are put through a cotton gin. The seeds and fibers are separated. Then the oils are pressed out and the rest of the seed is used to feed livestock because of the high protein content.

    Zygote: a cell which lacks a cell wall and results from the fusion of gametes

    Endosperm: the nutritive tissue formed within the embryo sac of seed plants. It is often consumed as the seed matures.

    Integuments: the external layer of an ovule that will develop into the seed coat

    Cotyledons: generally two (in dicots) seed leaves that store food


To see a labelled diagram of an ovule developing into a seed click on the image to the left.

Chronology of the Fruit and Seed Maturation Process:

Day 1: stimulation to form the flower
Day 8: number of pistils and anthers established
Day 17: number of ovules established
Day 18: meiosis in pollen
Day 26: megaspore meiosis
Day 33: corolla expands
Day 37: fiber differentiation
Day 40: flower opens, anthers dehisce, fiber initiation
Day 41: fertilizatin of the egg and polar nuclei, division of the primary endosperm nucleus, and the zygote shrinks
Day 43-44: zygote divides
Day 45-46: ovule integument division stops and the fuzz fibers are initiated, ovary enlarging rapidly, and globular embryo cells dividing
Day 52-53: endosperm becomes cellular around the embryo, embryo differentiation begins
Day 54-56: secondary deposition on fibers, embryo elongates, fibers begin slow accumulation of calcium, outer integument begins rapid weight increase
Day 60: endosperm completely cellular and at a maximum weight, fiber elongation slows
Day 65: fiber elongation complete, cotyledons complete, embryo at a maximum length
Day 70-72: embryo gains weight, endosperm nearly depleted, cellulose depositing on the fibers. Embryo contains oils and proteins and azquiring other nutrients
Day 82: boll nearly at maximum capacity, cellulose depositing stops on the fibers
Day 85-90: inner change in seed hormones and enzymes in the seed coat hardens, boll sutures and dehisces

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Introduction | Flowers&Fruit | Roots | Stems | Leaves

© Thomas L. Rost 1998
Section of Plant Biology Division of Biological Sciences