Morphology of Cotton plant

Botanical Name: Gossypium sp

Family-Malvaceae

Morphology of Plant 

In the wild state, cotton is a perennial plant, which attains a height of 5-6 m, but most of the cultivated cottons are annuals. Cultivated cotton is a herbaceous plant. 

Roots: 

• Cotton plant has a tap root system with secondary roots that branched laterally from primary root. 

Stem: 

• The main stem is erect and much branched; the branches develop from buds located at the nodes of the main stem. 
• There are 2 buds at the base of each cotton leaf petiole. 
• The first one are true axillary buds develop in a vegetative branch, which only bear leaves and no flowers. 
• Another one is accessory bud generally develops into sympodial or fruiting branch

Leaves: 

• The leaves are spirally arranged on the main stem and vegetative branches, except on fruiting branches. Where they form 2 alternate rows. 
• The leaves are petiolate. 
• The outline of leaf is more or less cordate with 3-9 lobes depending on variety. 
• The leaves are green but in some species such as in G. arborium leaves contain some purplish color.

Dimorphic branching in cotton plant 

• The main stem of the plant is monopodial in growth and carries spirally arranged leaves and branches, but no flowers. The leaves bear two kinds of buds: Axillary and extra-axillary. Cotton plant shows DIMORPHIC BRANCHING – monopodial and sympodial. The former develops from the axillary buds of the lower nodes of the main stem, sympodial branches arises from extra-axillary buds.
• Main axis have monopodial branching from it arises monopodial and sympodial lateral branches, the lower ones are the vegetative branches/monopodial and upper ones are reproductive/sympodial branches.
• Vegetative branches are morphologically similar to main stem but it does not bear flowers directly, it gives out secondary branches that are truly sympodial since a flower is borne at the tip.  
• The only difference between a vegetative branch (monopodium) and a fruiting branch (sympodium) is that the fruiting branch apical meristem, after making a true leaf, terminates in a flower. A vegetative branch continues to make leaves until some stress causes it to cease growth.

Fruit:

• The cotton fruit (boll) is a spherical or oval leathery capsule consisting of three to five locules or chambers which correspond to the carpel number. 
• The content of each division is called lock within which seeds are present.

Cotton Fiber:

• The cotton fiber is simply as elongation or outgrowth of an epidermal cell of the seed coat. 
• The long outgrowth forms the staple or lint while shorter out growth forms Fuzz.
• The cotton fibres represent epidermal elongations of the seed coat cells. The fibres attain maturity and full length during the first twenty-five days of boll development. 
• A mature fibre looks like a translucent, flattened twisted more or less tubular structure with broad base and an untwisted tapering apical end.
• A raw cotton fibre consists of 94percent cellulose, protein 1.3 per cent, pectic substances 0.9 per cent. 
• The fibres are classified as long staple and short staple fibres. 
• The long staple fibers are of American or Egyptian origin and have length of 1 to 2.5 inches, good texture and lusture. 
• Short staple fibers are of Indian origin and have length of about 0.3-0.7 inches and are coarse and lusterless. 

Cultivation and Processing:

• Cultivation Cotton is a tropical crop. 
• The crop requires abundance of sunshine and a warm temperature of 21-43° C. 
• The cultivation requires adequate soil moisture i.e. about 100 cm of rainfall during early stages of growth and a dry season during flowering and fruiting. Harvesting is done six months after sowing.
• Cotton bolls are handpicked. 
• The fibre is taken out and it is spun into yarn and woven into cloth. 
• The fibre passes through various processes such as ginning, baling, carding, picking and combing. Because of its superior quality, cotton is widely used in textile industry.