Botany of Banana

Parts of the Banana

Cultivated bananas are parthenocarpic, which makes them sterile and unable to produce viable seeds.

Fibrous adventitious root system
Root depth was strongly influenced by soil type and drainage
Positive correlation between bunch weight and quantity of roots producted.
Root system confined mostly to the upper 40 cm of soil because of unfavorable subsoil conditions produced less bunches.
No new root emissions after 75 to 90 days after planting or when 6-10 leaves had developed.
Root growth was best at day /night temperature of 25/18° C .
Extent of root growth radially and in depth was a good yield indicator.

The real stem is underground called rhizome.
A single, lateral, vegetative bud which is positioned 180o C from the axil of the leaf is a generic feature
The apparent, unbranched, errect and areal pseudostem is formed by the long, stiff and sheathy leaf bases which are rolled around one another to form an aerial pseudostem.
Shaft - the central axis that is concealed at the bottom of the pseudostem.
At the time of flowering, the shaft elongates, pierces through the pseudostem and produces an inflorescence terminally.
Musa is monocorpic perennial, because it produces flowers and fruits once during its life time

The leaves are spirally arranged and consist of asheath, a petiole and a blade.
The sheaths are nearly circular and tightly packed into non woody pseudostem which is functioning as the trunk of the plant. They are much longer than the blades.
The petiole is rounded beneath and channeled above
In general, shape of the blade is blunt at the tip and tapered, rounded or even auriculate at the base. It is thickest near the mid rid and thinnest at the margins.
The veins of the lamina are parallel with each other.

The inflorescence is branched spadix.
The flowers are protected by large, brightly coloured, spirally arranged, boat shaped bracts called spathes.
When the flowers open, the spathes roll back and finally fall off.
The flowers are polygamous i.e. staminate flowers, pistillate flowers and bisexual flowers are present in the same plant.
The male flowers lie within the upper bracts, the female flowers within the lower bracts and the bisexual flowers within the middle bracts.

Flowers are placed in the axils of the bracts, arranged biseriately and commonly number about to 12 to 20 per node.
Basal flowers behave as pistillate flowers while the terminal ones as staminate. At the lower end, they form a bulbous male bud.
The axis beyond the female phase is generally bare, but in some cultivars flowers and bracts are retained.
The intermediate flower clusters are of transitional stage structure and are fuctionally male. Individual flowers are ebracteolate.

Tepals 6 arranged in two whorls of 3 each, free or united.
In Musa, the three tepals of the outer whorl and the two lateral tepals of the inner whorl are fused by valvate aestivation to form 5 toothed tube like structure.
The inner posterior tepal is alone free.
It is distinctly broad and membranous.

Basically stamens 6, in two whorls of 3 each, arranged opposite to the tepals.
Only 5 stamens are fertile and the inner posterior stamen is either absent or represented by a staminode.

Ovary inferior, tricarpellary, syncarpous, trilocular, numerous ovules on axile placentation.
The style is simple and filiform. The stigma is three lobed.

In edible bananas, the fruit develops by vegetative parthenocarpy i.e. the ovary develops into a mass of edible pulp without the fertilization and even without the stimulus of pollination. So the fruits are seedless.
In the bunch, each cluster is called hand and the individual fruit is called a finger.
Fruit is a berry and has a leathery epicarp, slightly fibrous mesocarp, and fleshy endocarp.